UNBiology1a

School Science Lessons
Biology experiments
Updated: 2008-08-19 R
Biology names

Table of contents
9.0.0 Angiosperm reproduction
9.1.0 Asexual reproduction, vegetative reproduction
9.2.0 Asexual reproduction, vegetative reproduction, artificial methods
9.3.0 Sexual reproduction
9.4.0 Germination
9.5.0 Fruits and seeds
9.9.0 Plant growth

9.1.0 Asexual reproduction, vegetative reproduction
9.81 Bulb, daffodil, garlic, hyacinth, jonquil, leek, narcissus, onion (yam bulbil)
9.82 Corm, anemone, banana, crocus, gladiolus, Oxalis, taro,
9.83 Rhizome, bracken fern, canna, couch grass, ginger, iris, Jerusalem artichoke, mint, tumeric
9.84 Runners, strawberry
9.85 Stem tuber, potato (Irish potato)
9.86 Stem tuber, potato, starch grains
9.87 Tuberous roots, beetroot, carrot, dahlia, dandelion, turnip, parsnip, skeleton weed, sweet potato
9.1.3 Lignotuber, Banksia, Eucalyptus
9.1.8 Tuberous roots, root tuber, carrot, turnip, parsnip, beetroot, sweet potato, dahlia, skeleton weed, dandelion, lesser celandine
5.16 Planting material

9.2.0 Asexual reproduction, vegetative reproduction, artificial methods
9.2.6 Division, bulbs, corms, rhizomes, Michaelmas daisy, delphinium, suckers of raspberry canes
9.88 Auxins, growth substances
9.89 Cuttings, cutting powder, "Root Strike", growth substances, auxins
9.90 Cuttings, leaf cuttings, Begonia
9.91 Cuttings, root cuttings, phlox, hollyhocks, wild cherry
9.92 Cuttings, stem cuttings, top cuttings, blackcurrant, chrysanthemum, fuchsia, geranium, poppy
9.93 Grafting, bud grafting, orange, rose, fruit trees, apple, pear, plum
9.94 Grafting, shoot grafting, citrus
9.95 Layering, air layering, blackberry, carnation, clematis, rhododendron, rose, rubber plant
9.96 Whip and tongue grafting, fruit and ornamental trees
9.97 Plant parts will grow roots

9.3.0 Sexual reproduction of angiosperms, flowers
9.98 Parts of a dicotyledon flower
9.99 Inflorescences
9.100 Fruits and seeds, types of fruits
9.101 Dispersal of seed and fruit
9.3.1 Parts of a dicotyledon flower, e.g. hibiscus, tomato, lily, chilli, buttercup, Delphinium, Caltha, Capsella
9.3.2 Buttercup, cuckoo-bud
9.3.3 Cherry flower
9.3.4 Hazel flower
9.3.5 Monoecious, dioecious and hermaphrodite plants
9.3.6 Tulip, lily
9.3.7 Willow flower, Salix
9.3.8 Inflorescences, buttercup Ranunculus
9.3.9 Stamens and the production of pollen, Lilium
9.3.10 Pollen grain and male prothallus
9.3.11 Carpels and ovules, Ranunculus, Lilium, marsh marigold
9.3.12 Fertilization, Lilium
9.3.13 Development of the zygote, shepherd's purse
9.3.14 Post-fertilization fate of the endosperm
9.3.15 Post-fertilization developments outside the embryo sac
9.3.16 Flowers in different stages of maturity
9.3.17 Post-fertilization changes outside the ovule
9.3.18 Fate of the parts of the flower, floral organs
2.31 Collect flowers (Primary)
4.29 Bean flower (Primary)

9.5.0 Sexual reproduction of angiosperms, fruits and seeds
9.100 Fruits and seeds, types of fruits
9.101 Dispersal of seed and fruit
9.5.0.1 Classification of fruits
9.5.1 Dehiscent fruits
9.5.2 Succulent fruits
9.5.4 Albuminous seed, castor oil plant
9.5.5 Exalbuminous seed, broad bean
9.5.6 Germinating seeds
9.5.7 Germinating pollen
9.5.8 Achene
9.5.9 Samara
9.5.10 Nut
9.5.11 Schizocarp
9.5.12 Observe fresh-picked legumes
1.24 Seeds and seed pods (Primary)
2.32 Collect seeds (Primary)
3.29 Seeds and fruit (Primary)
4.30 Bean seeds and pods (Primary)

9.9.0 Plant growth
9.102 Growth of a radicle, zone of elongation, broad bean root
9.103 Growth of young shoot, sunflower, castor bean seedlings
9.104 Grow of the first internode, runner bean seedlings
9.105 Seedlings growing in the light and in the dark, pea
9.106 Grow plants in the classroom without soil
9.107 Mitosis in onion root tip cells
9.9.1 Measure plant growth
9.9.7 Nodules and galls
9.9.8a Meiosis in grasshopper testes
9.9.9 Development of plant embryo
9.9.10 Growing plant embryos.
9.9.11 Germination from seed to plant
9.9.12 Function of cotyledons
9.9.13 Natural growth inhibitors
9.9.14 Zone of elongation of growing root
9.9.16 Germination and early development of a bean plant
9.9.17 Grow plants in the classroom without soil
9.9.18 Soil-less culture (hydroponics), Knop's solution
9.9.19 Mineral deficiency experiment
4.31 Watch seedlings grow (Primary)
6.33 Fertilizing soil (Primary)
6.34 Chemical fertilizers (Primary)

9.1.1 Bulb, daffodil, hyacinth, jonquil, narcissus
See diagram 9.194.1: Narcissus bulb | See diagram 9.81: Bulb of Narcissus
1. Cut the bulb of an onion longitudinally through the middle. Note the stem, the outer membranous and inner fleshy scale leaves, and the large central bud containing the rudiments of foliage leaves and the flower. Dissect a bulb and note the presence of buds in the axils of the scale leaves. Cut a bulb transversely and note the arrangement of the scale leaves. Investigate the nature of the food reserves with iodine solution. Compare the bulbs. Grow bulbs and investigate the origin of new bulbs.
2. A bulb is an aggregation of fleshy leaf base developed on a short disc-like stem. It is protected by a series of thin, membranous, scale-like leaf bases. The scale leaves are the swollen bases of the vegetative leaves. They are composed of parenchyma cells and are swollen with food stored during the growing season. A longitudinal section shows a terminal bud or growing point, surrounded by the vegetative leaves, with the flowering stem in one of their axils. In Narcissus, unlike most bulbs, the flowering shoot is thus lateral to the growing point, is not directly involved in the formation of the shoot, so persists from year to year. The bases of the vegetative leaves swell to form the new fleshy scales, bulb scales, as their organic material passes down to the base. Axillary buds in the axils of the outermost scales may form two daughter bulbs. The innermost scales are the most recently formed, and the outer scales represent the bases of leaves of previous seasons. The stem is flat with many adventitious roots at its base. In onion or hyacinth the growing point produces a flowering shoot with leaves that terminates its growth. Axillary buds arising in the axils of fleshy scales grow at the expense of food synthesized in the green leaves or stored in the bulb scales and enlarge to form the bulbs for the next season. The surface of the bulb is covered by the thin papery exhausted scales of the old bulb. The bulb is a very condensed shoot with extremely short internodes and with leaf bases swollen with stored food.

9.1.2 Corm, Gladiolus, crocus
See diagram 9.82: Gladiolus corm | See diagram 9.82: Gladiolus corm
1. A corm is the swollen base of the flowering stem. Its surface is sheathed in the bases of withered leaves forming membranous brown scales. Remove the scales to see thin depressed scars where axillary buds form. The upper axillary buds form the next season's leaves and flowering shoot. The lower axillary buds form lower cormlets that can separate and can reproduce vegetatively. Cut longitudinally through the middle of a corm, passing through one large bud. Test the cut surface of the stem with iodine solution. The taro corm is an underground stem swollen with stored starch. Like other stems it has these parts: The growing point or a shoot apex. Many leaves joined to the shoot apex. Leaf scars are seen as circular marks that go around the corm. Axillary buds form just above the place where the leaf was joined to the stem. The axillary buds can grow into little corms or "cormlets" (cormels). The cormlets can grow into suckers.
2. The growth of the vegetative leaves and flowering axis uses all the food stored in the old corm but it can be seen below the new corm for some time. The base of the flowering shoot gradually becomes swollen using the food transferred from the leaves, and probably from the old corm also. This basal stem swelling is the young corm, sheathed in the bases of the lower leaves of the flowering shoot. At the close of the flowering period, the leaves and flowering stem wither and their stored food transfers to the swollen stem base while buds are produced in the axils of the withered leaves. See much starch in the outer part of the corm in a vertical section stained with iodine solution. Also, many scattered vascular bundles pass longitudinally to the uppermost buds and others pass laterally into the leaf bases. At the top of the corm are scars left by the withered flowering stem and foliage leaves. The flowering shoot of the next season develops from an upper bud in the axil of a scale leaf. Each new corm is lateral to that of the previous season because it arises as a flowering shoot from a lateral bud in the axil of the uppermost scale loaves.
3. Observe the corm of crocus. In the autumn, note the flattened swollen stem, the adventitious roots, the membranous scales encircling the stem, and the axillary buds. One or more buds near the top of the corm are strongly developed. Cut longitudinally through the middle of a corm and passing through one large bud. Examine the cut surface and note the structure of the bud with its axis, scale leaves, foliage leaves and central flowers. Test the cut surface of the stem with iodine solution. Grow corms and trace the development of the flowering shoot and of the new corms. Note that the old corms of are persistent. Note also that some axillary buds produce widely spreading underground stems that terminate in new corms.

9.1.3 Lignotuber, Banksia, Eucalyptus
A lignotuber is a swollen region where the trunk and roots meet. It enables the plant to survive fires.

9.1.4 Rhizome, ginger, iris, Jerusalem artichoke, mint, couch grass, Solomon's seal, bracken fern, canna, tumeric
See diagram 9.9.3: Iris rhizome | See diagram 5.6.8 Ginger rhizome ! See diagram 9.83: Ginger
1. A rhizome is part of a shoot with reduced scale-like leaves. It usually develops horizontally and underground. The apex sends up stems or leaves. The rhizome is composed of a series of segments that have arisen from axillary buds. At the apex of each segment is the apical bud, terminal bud, that forms the large strap-shaped, vertical, sheathing leaves and the flowering axis. The ginger rhizome is hard and compressed sideways. Inside it is pale yellow. It is covered with scales and has fine fibrous roots. The "stem" of the banana is a false stem, pseudostem. The true stem is an underground stem, a rhizome. The swollen stem base is a corm with very short internodes. The corm makes shoots that grow into branches or other corms. New plants come from these shoots. Suckers grow from the dormant buds called "eyes" on the corm. Each sucker formed is higher than the corm it came from. If the land is sloping, the suckers are usually formed on the uphill side so generations of banana plants will gradually move up a hill.
2. Development of the flowering axis stops further growth of the segment. Axillary buds just behind form new branches of the rhizome. They also have terminal buds that later form leaves and a flowering axis. Each segment is marked by a series of concentric circles that represent the bases of the former sheathing leaves formed at the nodes. Axillary buds are associated with the circles. Fibrous adventitious roots develop from the under surface of the rhizome. The rhizome can be separated into segments. Each segment can reproduce the plant if it has a growing point. The rhizome is a food storing organ, accumulating much starch. Note the position of the aerial shoots and the way in which more growth of the rhizomes can continue. Note at each node a scale leaf with an axillary bud or branch. Adventitious roots also arise at the nodes. Note how the system becomes progressively more extensive. Note the presence of scale leaves, axillary buds, and adventitious roots.

9.1.5 Runners, strawberry
A runner is a stolon, i.e. a long lateral shoot producing roots at intervals. The shoot between the roots dies to form new individual plants. Plant a well-developed strawberry plant in spring in a dish. Put the dish on a windowsill and water regularly so that the soil does not become either too moist or too dry. Note the runners that grow out of the leaf axils. Note the runners that grow out of the leaf axils. Small leaves appear at their tips. Roots develop which anchor the tip of the runner in the soil and the leaves appear. A new strawberry plan forms.

9.1.6 Stem tuber, potato
See diagram 9.9.5: Potato tuber
A stem tuber is the swollen end of an axillary underground branch developed at one of the lower stem nodes from dormant axillary buds called "eyes". Each eye can reproduce the plant. Cut the potato and test the cut surface with iodine solution. Thin layers of cork cells cover the tubers formed from phellogen, cork cambium, layers in which lenticels form. The eyes are within slight depressions with rims on which the scale leaves form, arranged in a distinct spiral. At the apex of the tuber is the terminal bud. At the opposite end is the scar of attachment to the stem that develops the tuber. The tuber is composed of thin walled living and intercellular spaces, and containing large quantities of starch grains of characteristic shape and protein. This stem tuber is different from the root tuber of sweet potato, dahlia, lesser celandine.

9.1.7 Stem tuber, potato, starch grains
See diagram 2.1.7: Starch grains | See diagram 9.86: Potato cell
Scrape a freshly cut surface of a potato tuber with a blunt knife. Transfer some milky fluid on the knife to a drop of water on a slide, then add a coverslip. Find isolated grains under low power then high power. Note the structure of the starch grains. Each grain has a hilum and eccentric stratification

9.1.8 Tuberous roots, root tuber, carrot, turnip, parsnip, beetroot, sweet potato, dahlia, skeleton weed, dandelion, lesser celandine
See diagram 61: Sweet potato tuber
1. In many biennials and perennials the main tap root, and sometimes the chief lateral roots, is very much swollen with stored food. When the aerial organs have died down, they preserve the plant until the next season. In these tuberous roots the new shoot develops at the expense of the reserve foods.
2. The cambium in these tuberous roots forms much xylem parenchyma and few lignified elements. The food surplus is stored in the xylem parenchyma. Weeds with tuberous roots may be broken up during cultivation, develop adventitious shoot buds and propagate the weed. Axillary buds at the base of the foliage leaves also propagate the plant readily. In the dandelion, a peculiar longitudinal contraction of the tuberous taproots wrinkles its surface, and pulls the radical leaves downwards to the soil surface. At times the plant may form a shallow saucer-like pit on the surface of the soil. Similar contractile roots are also developed by crocus, gladiolus, and oxalis. They drag the bulb, corm, or rhizome from which they arise, more deeply into the soil. In gladiolus, each new corm arises on top of the old one and is higher in the soil, but the contractile roots at the base of the corm pull it down to a lower level. Aerial shoots (suckers) also result in vegetative reproduction. They arise from adventitious buds on the roots, and produce new aerial shoots as in begonias, plums, apples, poplars, and many other plants. Some botanists in USA refer to the storage organ of the sweet potato as a root, not a tuberous root, because only the swollen end of an axillary underground branch is a tuber, potato, Irish potato. Note the fibrous, normal roots, and the club-shaped root tubers.
3. Examine plants at various seasons of the year and trace the origin and mode of development of the root tubers.

9.2.1 Auxins, growth substances
Put oat, barley or wheat grains in a flat dish containing tap water. The next day, sow them in a pot. When the seedlings are 3 cm high, cut off 10 mm from the tips of the two thirds of the shoots. Leave one third of the seedlings not treated as a control. Dissolve 1 g of gelatine, with heating, in 20 mL demineralized water. Use this solution to stick back the shoot tips on half the cut seedlings. Note any further growth. The seedlings without a shoot tip stop growing. The seedlings with the shoot tips stuck on again continue to grow almost as much as the control seedlings. The growth substance, auxin, diffuses out of the replaced tips through the gelatine into the cut end, and allow the plant to continue to grow. Under the influence of light, substances form in plants that, in specific concentrations, trigger cell division and cause elongation. These growth substances (auxins) are found especially on buds and root tips.

9.2.2 Cuttings, cuttings powder, "Root strike", growth substances, auxins
1. Use plant cutting powder, rooting powder, to stimulate and produce healthy roots on cuttings. The active constituents of the powder are indole acetic acid, IAA, the main auxin of most plants, or indolebutyric acid, and naphthalene acetic acid. Select healthy end growth 10 mm or less in diameter after the growth period of the plant. Cut at an angle or select a "heel", where a branch joins. Cuttings leave two terminal leaves. Moisten the cut end of the cutting, dip it into the cutting powder and plant into free draining soil. Water the cuttings daily. If you plant next to the side of a glass jar, you can observe roots forming near the cut surface.
2. Commercial plant striking hormones are indole acetic acid or indolebutyric acid. A cutting should be 50 mm to 150 mm long with an end growth diameter of 100 mm or less. Take three cuttings from the parent plant after the growth period, i.e. late summer or early autumn. For shrubs that flower in winter, e.g. camellias or daphnes take cuttings in midwinter. For shrubs that flower in the spring, e.g. azaleas, take cuttings in autumn. For roses, take cuttings from new growth in late autumn, early winter. Make an angled cut to take a healthy cutting from a parent branch. Remove the bottom leaves but leave three small leaves at the top of the cutting. Take cuttings in early morning or late afternoon. Immediately put in water after cutting and as soon as possible apply plant striking hormone by pushing the cutting into the bag of powdered hormone. The potting mix used for the initial root stage should be free flowing and light weight. However, free draining sandy loam can also be used. Store the plant striking hormone in a dark cool place and do not let it contaminate streams, ponds or soil.

9.2.3 Cuttings, leaf cuttings, Begonia
The Begonia leaf forms adventitious roots. Make cuts in the veins below the leaf. Plant the cut leaf in the soil and water.

9.2.4 Cuttings, root cuttings, phlox, hollyhocks, wild cherry
Cut horizontally at the top of the root and cut at an angle at the base for easy insertion. Also, the top of the plant above the ground can be cut off to form new shoots.

9.2.5 Cuttings, stem cuttings, top cuttings, geranium, poppy, fuchsia, chrysanthemum, blackcurrant.
See diagram 9.2.5 | See diagram 9.9.1: Cuttings, plantingmaterial
1. Put one end of a cut stem in damp sand. Note the wound tissue, callus, that develops from which roots form. At the other end, dormant lateral buds form new shoots.
2. Cut two pieces of stem with leaves, from a geranium plant. The most suitable are short, compact shoots on which the leaves are close together. A cut is made just underneath a stalk bud. Fill two flowerpots with sandy soil to just below the rim. Plant a cutting half a finger length deep in each pot. Press the soil firmly down around the stem and add water so that it packs closely around the cutting. Put an inverted beaker over each cutting. Label each flowerpot and put in the light but not direct sunlight. Water the cuttings regularly. The cuttings develop into new independent geranium plants.
3. Cuttings can form adventitious roots. You can propagate poppies, geraniums, fuchsias, chrysanthemums and black and red currants by cuttings. Fill two flowerpots with sandy potting compost. Take two cuttings with leaves on attached from a geranium. Make the cut close to and just under a bud. Sturdy shoots with leaves close together are the most suitable. Remove the bottom leaves from each cutting. Plant each cutting 3 cm deep in a flowerpot and water well so that the soil is packed tight around the cuttings. Put a beaker over each cutting but making sure you allow air to get in and out. Keep the soil moist and do not expose the cuttings to direct sunlight. After some time the shoots begin to grow. At the point where the cut was made adventitious buds have formed and have put out roots. This is the way a cutting develops into an independent plant.

9.2.6 Division, bulbs, corms, rhizomes, Michaelmas daisy, delphinium, suckers of raspberry canes
Pull apart the diffuse plants with many shoots or offsets. Adult cells of plant organs may revert to meristematic activity and reveal their original embryonic characters.

9.2.7 Grafting, bud grafting, orange, rose, fruit trees, apple, pear, plum
See diagram 9.93: Shield graft | See diagram 9.93: Budding and grafting, shield graft, saddle graft
1. Remove a bud from a plant with a small strip of bark and cambium, then insert it into a T-shape slit in the stock. Tightly bind and wax the parts. If the two areas of cambium are in contact, they produce a callus that unites scion and stock. To obtain good quality fruit select only the best buds for the graft.
2. Bud grafting allows the following:
2.1. rapid multiplication of desirable plants from a single individual,
2.2. preservation of a type that does not come true from seed, navel orange and hybrids,
2.3. modification of the scion, apples and pears are grafted to dwarfing stocks to grow a smaller tree for convenience of size,
2.4. improved yield, grape varieties may yield better when not grown on their own roots,
2.5. extended climatic ranges using extreme climate tolerant root stocks,
2.6. disease resistance by grafting susceptible scions to resistant stocks.

9.2.8 Grafting, shoot grafting, citrus
See diagram 9.93: Saddle graft
The scion and stock will fuse to form a single plant. A shoot from such a graft shows the character of the scion, not of the stock that nourishes the scion. Successful grafts are usually between closely related plants. Citrus trees can be grafted on rootstocks of Poncirus trifoliata. Insert a cut twig, the scion, into an incision on the stem or root of another plant, the stock. Bind the two tightly together to give firm contact between the cut surfaces. Cover the join with an antiseptic wax to prevent infection. The cambium tissue of the cut surfaces of the scion and stock form a mass of callus, soft, thin walled parenchyma, that joins the two surfaces together.

9.2.9 Layering, air layering, carnation, rubber plant, lilac, rhododendron, rose, clematis, blackberry
Bend a branch down over the soil and fix pegs so that some nodes are below the surface. Adventitious roots grow from the buried nodes. The axillary bud near the peg grows upwards into an aerial shoot. Cut the layered stem from the parent plant and let it grow independently. For air layering of the rubber plant, make a longitudinal cut below a node almost to the centre of the stem. Treat the cut with plant cutting powder then bind on moist cotton wool covered with polythene film. Roots form in the layering.

9.2.10 Whip and tongue grafting, fruit and ornamental trees
See diagram 9.96: Whip and tongue graft | See diagram 9.96: Whip and tongue grafting
Cut the stock within 10 cm of the ground level. Make a long slanting upward cut on the stock about 4 cm long. Make a small downward cut on the stock to form a tongue near the top of the slanting cut. Make a similar slanting downward cut on the scion, leaving a bud midway on the opposite side of the cut. Make a tongue on the scion to correspond with the tongue on the stock. Fit the tongue of the scion neatly into the tongue of the stock to hold the graft firmly in position. The cut surfaces must be flush. Bind the graft with moistened string and apply some warm grafting wax or bituminous tree dressing, "Arberex" to make the joint airtight and watertight. In all grafting the vital area is the "cambium layer", the thin green layer that lies between bark and wood. See it in any young stem that is cut through diagonally. The cambium cells retain the power of growing and knitting with similar cells. When grafting, the cambium of the scion must be in direct contact with the cambium of the stock so the nearer the two cut surfaces can coincide in length and width the better. Other methods of grafting include the following: clematis (root grafting), rhododendron (saddle grafting), birch (inarching, one tree to another).

9.2.11 Plant parts will grow roots
Obtain a box of sand and put it away from direct sunlight. Wet the sand thoroughly and keep it moist.
Plant any of the following in the sand:
1. various bulbs,
2. cuttings of Begonia and Geranium stems,
3. a section of sugar cane stem with a joint buried in the sand,
4. a section of bamboo stem with a joint buried in the sand,
5. carrot, radish and beet tops, each with a small piece of root attached,
6. an onion,
7. an iris stem,
8. pieces of potato containing eyes,
9. (i) a branch of willow.

9.3.1 Parts of a flower, tomato, lily, chilli
See diagram 9.50.1: Parts of a flower | See diagram 5.4.2: tomato flower | See diagram 9.98.1: Lilium flower | |See diagram 54: Chilli flower

9.3.2 Buttercup, cuckoo-bud
Note the number, arrangement, shape and colour of each set of organs, viz. sepals, petals, stamens and carpels then dissect the flower. Note that the sepals are pale green, boat-shaped, and covered, on the outside with hairs. The petals are yellow, larger than the sepals, heart shaped, and each bears a nectary at its base. Each stamen is divided into two main portions, the filament and the anther head, whereas the carpels are free and each is composed of an ovary, a style and a stigma. Half a flower should then be drawn. This shows the relative positions of the various organs of each whorl as they are set upon the receptacle. This should be followed by a true longitudinal section, which shows only those organs through which the scalpel passes when cutting the flower longitudinally. A floral diagram should then be drawn, and the whole study completed with a floral formula.

9.3.3 Cherry flower
1. The cherry flower has male and female flowering parts in one flower. On the outside are the sepals, then the petals, then the male parts, the stamens, and in the middle of the flower is the female part, the pistil. A flower that contains both female and male parts is called a hermaphrodite. Hold a cherry flower by the stem and detach all the individual parts with tweezers. Begin with the outer parts of the flower and work inwards. Finally, cut off the part of the stem in the middle of the flower. Put similar parts in groups and arrange the groups on the table in the order in which you detached the parts from the flower. The first group are the sepals. They form the calyx that protects the bud before blossoming. Note their colour, shape and number. The second group are the petals. They form the corolla, protecting the inner parts of the flower and attract insects. Note their colour, shape and number. The third group are the stamens. Note their colour, shape and number. Use a magnifying glass to see a thin stalk, the filament, with an anther on top that contains the pollen. The last part cut away from the stem is the pistil. The pistil has of three sections. The convex lower section, adjoining the stem, is the ovary, which merges into the style at the upper end. The tip of the style is called the stigma.
2. Study a cherry blossom with the naked eye and then under a magnifier.
Note the following:
1. The small, green, outer leaves, called the sepals that form the calyx, which protects the flower bud before it opens.
2. The white petals that form the corolla protect the inner parts of the flower and attract insects.
3. The stamens, on and above the petals. Each stamen consists of a small thin stalk, the filament, on which the anther is mounted. The stamens are the male parts of the flower. The anthers contain the pollen.
4. The pistil is in the centre of the flower.
It consists of three sections:
4.1 The bulbous, lower section, which adjoins the stalk of the flower, called the ovary.
4.2 The style is attached to the upper end of the ovary.
4.3 The upper end of the style forms the stigma. The pistil is the female part of the flower.
5. To observe how the various parts of the flower are arranged and are related to each other, separate all the parts of the flower at their points of attachment. Use forceps, starting at the outside. Put similar parts together on a black piece of cardboard. Write the names next to the rows of the various parts of the flower. Study other flowers in the same way, e.g. columbine Aquilegia vulgaris, primrose Primula vulgaris, dog rose, snapdragon and apple blossom.

9.3.4 Hazel flower
The hazel flower is either male or female. The male flowers are grouped in catkins, and the female flowers are in the buds with the clusters of red threads. The two types of hazel flower are found on different parts of the same bush. In the spring find a hazel bush twig with catkins which are already flexible and loose. Hold the twig over a hard dark surface and hit the catkins with a glass rod. The yellow dust which falls is pollen, so the catkins are male flowers. The male parts of a flower are the stamens with filaments and anthers. The female part is the pistil with ovary, style and stigma. To see whether the male and the female parts are in hazel catkins use a magnifier to examine the most wide open catkin. On the flexible stem of the catkin are very many small leaf-like scales. They stand out from the stem of the catkin like small rooftops. As well as the catkins there are also buds on the twigs of the hazel bush with a bundle of fine red thread on their tips. Use tweezers and a dissecting needle to remove the small leaves and the scales which enclose the bud. Inside there are several green scale-like small leaves. To one side on the lower edge there are two small egg-shaped structures, the ovaries. The style and stigma of these ovaries are divided and are the red threads which jut out from the bud.

9.3.5 Monoecious, dioecious and hermaphrodite plants
Male and female gametes may be on the same flower or on different flowers:

9.3.6 Tulip, lily
Examine specimens of large simple flowers, tulip or Lilium. Count the stamens and observe how they are arranged about the central pistil. Make large diagrams of the essential organs. Label the parts of the pistil (stigma, style and ovary). Label the parts of the stamen (filament and anther). The end of the stalk on which the flower grows is called the receptacle. At the base of the receptacle there are usually leaf-like structures that enclose the bud. These are called sepals. Above the sepals there is usually a ring of brightly coloured petals called the corolla.

9.3.7 Willow flower, Salix
Collect willow branches with catkins beginning to open. Willows have two types of catkins, oval-shaped or round and, pale to bright golden yellow and oblong, cylindrical and a greenish colour. Note whether both types of catkin occur on one branch or on the same tree. Study an oval-shaped catkin by cutting longitudinally with a razor blade and using a magnifying glass. It contains many stamens which sit in pairs on a hairy leaf scale (bract). They form the male (or pollen) flower. Study an oblong, greenish catkin by cutting longitudinally with a razor blade and using a magnifying glass. Observe the many bottle-shaped greenish structures, the pistils (the female flower organs). Each pistil sits on a hairy leaf scale (bract). In the hazel tree male and female flowers are separate but on the same bush. Sex differentiated plants on which both male and female flowers are found on the same plant are called monoecious, sex differentiated plants in which the male and female flowers are found in different plants are called dioecious plants. Some dioecious plants possess fruits which can be eaten, e.g. sea buckthorn Hippophae rhamnosides. Its fruits are very rich in vitamin c and give a pleasant tasting juice.
When a plant flowers differs between species. Anemones, primroses, cherry trees and apple trees flower in spring. Larkspurs, roses and carnations flower in summer. Dahlias and chrysanthemums flower in autumn. Christmas rose flowers in winter.

9.3.8 Inflorescences, buttercup Ranunculus
See diagram 9.57.4: Types of inflorescence | See diagram 9.98: Different types of inflorescence
Plants can bear flowers singly or grouped in an inflorescence. Collect plants with different types of inflorescence. Note the peduncle, pedicels, and bracts, and their relative positions.
1. Each flower usually has its own stalk, the pedicel. Where the pedicels join the main stalk, the peduncle, is a bract.
2. A spike is a simple axis with successively younger sessile flowers, so it has no pedicels, e.g. Gladiolus, red clover.
3. A catkin is a unisexual spike without petals that usually hangs down, e.g. mulberry, willow, oak, birch.
4. A spadix is a fleshy spike covered with male and female flowers, e.g. arum lily.
5. A raceme is similar to a spike but the flowers have pedicels, e.g. sweet pea.
6. A panicle is an open, repeatedly branched raceme bearing many flowers, e.g. oats and other grasses.
7. A corymb is a raceme with all flowers at one level with the youngest flower in the centre, e.g. apple, rowan, hawthorn.
8. An umbel has flower stalks all arising together at the end of the main stalk, e.g. carrot, parsley, fennel, frangipani, Hydrangea, Lantana.
9. A capitulum, or head, has flowers densely packed on a common receptacle with the youngest at the centre, e.g. sunflower, dandelion, daisy.
10. A cyme has the main axis ending in a flower, the oldest flower, with younger flowers on lateral branches.
11. A spathe is huge bract that can enclose the inflorescence, e.g. coconut.

9.3.9 Stamens and the production of pollen, Lilium
See diagram 9.98.2: Lilium stamen
The stamens are attached to the receptacle inside the corolla and outside the carpels. Each stamen consists of a filament like a little stem and terminal anther that produces pollen. The anther has of four sporangia, each occupying a lobe. The sporangia are held together by parenchyma tissue with a small vascular bundle called the connective. An adnate anther is fused to the filament, Ranunculus. A versatile anther swings loosely at the end of the filament, Lilium. Most anthers open by a longitudinal slit down each side so that the pollen from the two contiguous sporangia is shed simultaneously. Some anthers shed pollen by terminal pores. A transverse section of a young anther shows four locules or sporangia, two on each side of the connective with its vascular bundle. Each sporangium has an epidermal layer of cells with a thin cuticle, a fibrous layer of cells, parenchyma cells, and a tapetum, composed of a single layer of cells with large nuclei and dense contents and projecting into the sporangium. The tapetum nourishes the pollen-mother-cells (spore-mother-cells) inside that have thick walls, dense cytoplasm, and a large nucleus. As the anther matures, each diploid pollen-mother-cell divides by meiosis to form four haploid pollen grains. The walls of the pollen-mother-cells break down to release the pollen grains. Dehiscence occurs between the two contiguous sporangia where the cells have thin walls and readily split apart under tension when the cells of the fibrous layer contract. The split extends down each side of the anther to liberate the dry pollen grains.
Cut sections of anthers Place the anthers of a lily flower, or other large anthers, in alcohol for about a week. Cut transverse sections, mounting in glycerine, and note the structure as described in the text. Also, buds of marsh marigold also harden alcohol and may be sectioned at the level of the anthers.

9.3.10 Pollen grain and male prothallus
See diagram 9.98.3: Lilium pollen grain
Each pollen grain contains a small generative cell and a large tube cell. Pollen grains shed from the anthers are carried by wind or by insects to a stigma, the receptive part of the gynoecium. Germination of the pollen is induced by the secretion from the stigma. The large tube cell divides to form the pollen tube that grows through pores in the wall of the pollen grain then grows down through the style tissue to reach the ovary. The small generative cell divides to form two male cells that function as gametes and may seem naked nuclei. As the pollen tube emerges from the pollen grain, the tube nucleus passes to the tip of the pollen tube leaving behind the two male cells. The pollen tube and its two small cells represent the male prothallus found in more primitive plant forms, liverworts, mosses, ferns and conifers. The germination of pollen grains can be studied using different concentrations of sugar solutions.
Observe the germination of pollen grains. Put fresh pollen in a 10% sugar solution for 12 hours and examine them with a magnifying glass. You may find germinating pollen on the stigma of a flower. Observe pollen stained with methylene blue under low power. Observe the germination of pollen in the styles of chickweed, taken from a flower which is just beginning to fade. Mount the styles in a dilute aqueous solution of methylene blue.

9.3.11 Carpels and ovules, Ranunculus, Lilium, marsh marigold
See diagram 9.98.4: Lilium gynoecium | See diagram 9.98.5: Lilium ovule
1. The carpels appear in the centre of the flower, and usually end the growth of the floral axis. Together the carpels form the gynoecium or pistil. An apocarpous gynoecium has separate carpels, Ranunculus. A syncarpous gynoecium has fused carpels, Lilium has 3 fused carpels. The gynoecium of legumes is a single carpel.
2. Each carpel consists of three parts:
2.1 The ovary at the base contains the ovules.
2.2 The style is an extension of the ovary.
2.3 The stigma at the end of the style secretes a sticky, sugary fluid to catch the pollen grains.
2.4 The ovule consists of a mass of cells, called the nucellus or megasporangium, surrounded by two rings of tissue called integuments.
3. The nucellus develops the diploid megaspore-mother-cell that divides by meiosis to form four haploid megaspores, while the megaspore-mother-cell becomes a large oval cell called the embryo sac. Of the four megaspores in a row in the embryo sac only the megaspore nearest the food supply and farthest from the micropyle survives because it crushes and absorbs its three sister megaspores. The surviving megaspore divides by three mitosis divisions to form the eight nuclei of the embryo sac (2 synergids, 1 ovum, 3 antipodals, 2 polar nuclei). At the micropyle end of the embryo sac are three nuclei or cells surrounded by cytoplasm with thin membranes. Two of these cells are pear shaped and called the synergids. The third cell is the globular ovum. At the other end of the embryo sac are three cells called the antipodals. In the centre of the embryo sac is the large fusion nucleus formed by the fusion of two polar nuclei. The embryo sac that represents the female prothallus is still surrounded by cells of the nucellus.
4. Placentation refers to how the ovules are attached to placentas in the ovary.
4.1 Parietal placentation is where the ovules are attached to the wall of the ovary, poppy.
4.2 Axile placentation is where the ovules are attached to the central axis of a multilocular ovary, Lilium.
4.3 Free central placentation is where the ovules are attached to the axis but the ovary is unilocular, primula.
5. The stigma is hollow or contains loose mucilage secreting cells to help the pollen tubes reach the ovarian cavity.
6. The pollen tube probably absorbs nutrients from this style tissue in flowers with long styles.
7. Cut sections of ovules. Take a just opened flower of marsh marigold and remove the sepals and petals. Harden the group of carpels in alcohol and then cut transverse sections of these. Cut a large number of sections and pick out a few thin ones which have traversed an ovule and mount in glycerine. These will give longitudinal sections of the ovules which can be compared with the figures in the text. Transverse sections of syncarpous ovaries should also be cut, tulip and lily.

9.3.12 Fertilization, Lilium
See diagram 9.98.6: Lilium fertilization
The end of the pollen tube in the cavity of the ovary, enters the micropyle, penetrates the nucellus tissue, enters the embryo sac and bursts to set free its two male gamete cells. One male gamete unites with the ovum to form the zygote, the essential act of fertilization. The other male gamete cell unites with the fusion nucleus to form the primary endosperm nucleus or triple fusion nucleus. The synergids and antipodals shrivel and die. In angiosperms the endosperm develops only after fertilization. The triple fusion nucleus divides to form thin walled parenchyma tissue that accumulates food reserves, starch, oil and protein. As the endosperm develops, it crushes the nucellus.

9.3.13 Development of the zygote, shepherd's purse
See diagram 9.99.1: Capsella embryo 1 | See diagram 9.99.2: Capsella embryo 2
The zygote forms a firm cellulose wall then divides transversely into a filament of three cells called the pro-embryo. The large cell nearest the wall of the embryo sac is the basal cell that attaches the embryo to the wall. The middle cell is the suspensor initial that divides transversely to form a short filament called the suspensor. The uppermost cell is the embryonic cell. As it is towards the centre of the endosperm, it is nearer its food supply and can divide frequently to form the greater part of the embryo. The embryonic cell divides by a transverse wall and then by two longitudinal walls at right angles to each other, to form the octants. Each octant then divides by walls parallel to the surface (periclinal) into an outer and inner cell. The superficial layer later divides only by walls at right angles to the surface (anticlinal) and forms the dermatogen, which produces the epidermis. The inner cells divide periclinally, so that inner and outer series of cells are formed. In the lower part of the embryo, this segmentation is much more regular than in the upper half the lower forms the hypocotyl and root, while the upper forms the cotyledons (seed leaves) and plumule (terminal bud). The central cells are the plerome, which produces the stele tissues, while the outer series is the periblem and produces the cortex. The uppermost cell of the suspensor is the hypophysis, which forms the root apex by division. Between the two cotyledons the small plumule arises at the base of the groove between them and terminates the hypocotyl. The hypocotyl and radicle with its root cap, have all developed from the embryo initial and the hypophysis of the pro-embryo. The greater part of the embryo, however, arises from the embryo initial. In monocotyledons a pro-embryo of three primary cells is formed as in dicotyledons. However only one cotyledon appears terminal on the hypocotyl, while the plumule arises laterally.
Examine stages in the development of the embryo of shepherd's purse A flowering shoot, freshly gathered, with a few flowers at the top of the raceme and a succession of fruits below will provide the necessary material. Remove ovules from a fruit which has attained a size about one third of that of a mature fruit. Place these in a drop of 1% caustic potash until they become transparent, cover and examine the general form of the campylotropous ovule. Then press gently on the coverslip. This should cause the embryos to escape from some of the ovules. Now irrigate with dilute acetic acid, a treatment which renders the embryo walls more apparent. Embryos squeezed out from the ovules of both older and younger fruits should be examined in the same way

9.3.14 Post-fertilization fate of the endosperm
See diagram 9.99.3: Capsella embryo
As the embryo develops it occupies a groove in the centre of the endosperm. In exalbuminous or non-endospermic seeds, legumes, the embryo absorbs the endosperm and food reserves are transferred to the large fleshy cotyledons. In albuminous or endospermic seeds the embryo remains surrounded by the endosperm.

9.3.15 Post-fertilization developments outside the embryo sac
In most angiosperms, the nucellus is exhausted by the development of the ovule. In ripe seeds, it may be present as a thin membrane between the endosperm and the seed coats. The integuments of the ovule form the permanent seed coats that are thin and membranous in some species hard and woody in others. When the funicle attaching the seed to the placenta dies, the seed is separated from the ovule and is ready for dispersal. When the seed is shed from the plant, it may not germinate because it requires a period of dormancy.

9.3.16 Flowers in different stages of maturity
Collect specimens of flowers in different stages of maturity, from newly opened buds to specimens in which the petals have fallen. Cut each ovary open, and note the changes that take place during seed development. Roses, apples and tomatoes are good for this purpose.

9.5.1 Dehiscent fruits
See diagram 9.100.8: Siliqua, silicula, follicle
1. The follicle of larkspur splits along its ventral suture. It is formed from one carpel and contains several seeds.
2. A pod is a dry dehiscent fruit with many seeds. The legume, pea, develops from a single carpel and splits along both margins. When the pea fruit is ripe, both parts of the pericarp twist to throw the seeds some distance from the parent plant.
3. Examine different types of siliqua and silicule, e.g. wallflower, shepherd's purse, honesty. These fruits are formed from two fused carpels, and are distinguished by the formation of a false septum. Note how they split to expose the seeds.

9.5.2 Succulent fruits
See diagram 54: Chillies | See diagram 5.6.3: Banana | See diagram 9.100.5: Apple | See diagram 55: Cocoa | See diagram 53: Coconut | See diagram 9.100.3.1: Pineapple | See diagram 9.100.10: Rose hip | See diagram 1.4: Pandanus
Note the complete fruit and longitudinal and transverse sections, berry (gooseberry, currant, chillies, tomato, banana, grape, orange), pepo (cucumber), drupe (plum, cherry, coconut, cocoa walnut) pome (apple, pear), aggregate fruits (blackberry, raspberry, pineapple, custard apple, rose hip, Pandanus).

9.5.4 Albuminous seed, castor oil plant
Note the embryo, with its hypocotyl, radicle and plumule. The cotyledons are thin and tissue-like. The seed is albuminous. Note the testa surrounding the seed. Test the food reserves present in the seeds.

9.5.5 Exalbuminous seed, broad bean
1. Soak the seed for twenty four hours before dissecting. Note the embryo, with its hypocotyl, radicle and plumule. The cotyledons are thick and fleshy. The seed is exalbuminous. Note the testa surrounding the seed. Test the food reserves present in the seeds.
2. Examine the soaked seed. Note the hilum, elongated brown scar, at one end of the seed. At this point the seed was attached by a stalk to the inside of the fruit.
3. Remove the testa, seed coat, to reveal the embryo. The embryo consists of two large fleshy cotyledons attached to a small axis. The tips of the axis are the radicle, embryo root, and plumule, embryo shoot. The radicle can be seen at one side where it was inserted into a pocket in the testa. Remove one cotyledon to reveal the plumule. Apply some dilute iodine solution to a broken surface of the cotyledon and note the positive reaction to the starch test.

9.5.6 Germinating seeds, life cycle of bean plant
See diagram 9.113.3: Germination of bean
The grains of wheat, barley and maize and the seeds of onion are suitable examples.

9.5.7 Germinating pollen
See diagram 9.123: Germinating pollen grain
Make a strong sugar solution and put it in a shallow dish like a saucer. Shake pollen from several kinds of flowers on to the surface of the sugar solution. Cover with a sheet of glass and let it stand in a warm place for several hours. Observe little tubes growing from the pollen grains. Use a magnifying glass.

9.5.8 Achene
See diagram 9.100.10: Achene, strawberry
Use a magnifying glass to examine the collection of carpels of the buttercup, when they have ripened after fertilization, thus forming a collection of fruit. Each fruit is an achene. Dissect one and find the single seed enclosed. Compare and contrast a ripe strawberry with the collection of buttercup fruits.

9.5.9 Samara
See diagram 9.100.10: Samara
Examine a bunch of ash fruits. Make a detailed examination of a single fruit and cut a longitudinal section of it, thus exposing the seed. Examine a double samara of the sycamore.

9.5.10 Nut
Examine a hazel nut, partly enclosed in its leafy cup. Examine the nut in detail and expose the seed. Compare this fruit with that of the buttercup. (Note: A "peanut" is not a nut.)

9.5.11 Schizocarp
See diagram 9.100.10: Schizocarp
Examine the schizocarp of the hollyhock, and compare this with the other types of dry, indehiscent fruits.

9.5.12 Observe fresh-picked legumes
Look over 1 kg of fresh picked peas or string beans or other legumes and pick out the pods that are not completely filled. Open these and compare them with fully filled specimens. The abortive seeds are the remains of ovules that were not fertilized by pollen.

9.9.1 Measure plant growth
See diagram 6.9.1: Measure plant growth

9.9.2 Growth of a radicle, zone of elongation, broad bean root
See diagram 5.6.1: Growth of bean root | See diagram 9.102: Growth of broad bean root
The increase in root length results from growth in the zone of elongation between the root tip and where the root hairs begin. Germinate a broad bean seed. When its radicle is 2 cm long, mark with Indian ink from the tip upwards at intervals of exactly a millimetre, for about 10 mm. Use a wide-necked jar with a cork lid and half full of water. Push a long pin through the cork and the seed to suspend the seedling in the jar with the root in the water. Wrap aluminium foil around the jar to keep the root in the dark. The next day, note how the ink marks have moved apart because of the growth of the root. The ink marks have moved different distances apart. The marks near the root tip have not parted much. The marks further away have parted further but the top marks and may not have parted at all.

9.9.3 Growth of young shoot, sunflower, castor oil seedlings
See diagram 9.0: Castor seedling
Do a similar experiment with a young shoot. Grow the seedlings on damp sawdust or potting mix.

9.9.4 Grow of the first internode, runner bean seedlings
When they are sufficiently developed, take daily measurements of the increase in length of the first internode. Record these measurements for 2 weeks then plot the data on a graph.

9.9.5 Seedlings growing in the light and in the dark, e.g. pea
Soak same-size seeds, e.g. pea or bean, in water and sow in same-size flowerpots. Put one pot in a well light place and the other pot in the dark. After the seedlings in the light grow to a height of 3 centimetres, compare the seedlings grown in the light and in the dark. Remove the plants from the pots, wash and dry them and weigh them. The etiolated plants grown in the dark are taller but their dry weight per plant is less than the plants grown in the light.

9.9.7 Nodules and galls
These are the result of growth stimulation by various agents: bacteria, viruses and insects. They may be beneficial, as are the root nodules caused by Rhizobium, a bacterium that fixes nitrogen when inside the root where a symbiotic association occurs. Some types are formed by parasitic associations, e.g. insect galls, or are pathological, e.g. sunflower gall and virus infections. Plants respond to the presence of the bacteria by producing auxins and kinins that are responsible for the abnormal cell division that lead to the swelling. Use young sunflower plants, half of which, about a week ago, received an inoculation of bacteria, Agrobacterium tumefaciens, which cause galls. Note normal growth and deformity caused by the bacteria.

9.9.8 Mitosis in onion root tip cells
See diagram 2.26: Microscope technique - staining | See diagram 9.109.1: Mitosis in onion root tip cells | See diagram 9.109.2: Cell division, onion root tip
In the onion root tip, before mitosis starts, interphase, granules in the nucleus have the staining reaction of chromatin that consists of DNA and proteins, mostly histones. During interphase DNA replication occurs so the chromosome appearing in prophase will have two identical sister chromatids.
Prophase: The loose coils of the chromatin network condenses to become the 16 chromosomes of the onion cell, double structures with two identical chromatids joined by a centromere. The nuclear membrane and nucleoli disappear. Prophase occupies about two thirds of the time taken for mitosis.
Metaphase: Curved microtubules, fibres, form a spindle outside the nucleus. The centromeres move to the central plane of the spindle, metaphase plate. The centromeres split in two.
Anaphase: The identical chromatids move to the opposite poles of the spindle to leave two identical sets of chromosomes and a new nuclear membrane appears around each set. The chromatids are now chromosomes.
Telophase: Nucleoli reappear. The chromosomes return to being chromatin granules.
Cytokinesis is the division of the cytoplasm between the new nuclei and the formation of new cell walls.
1. Put an onion in moist absorbent paper in a warm place to obtain roots. Cut off 1 cm lengths from the ends of roots and fix them in a solution of 1 part glacial acetic acid to 3 parts 95% alcohol. Leave for 24 hours. Put a piece of root in a drop of aceto-carmine on a slide. Cut off 3 mm of the tip and discard the rest. Gently warm over a spirit lamp. Place a coverslip over the drop of stain. With absorbent paper over your thumb then gently squash the pieces of root tip by pressing on the coverslip with a rolling motion. Do not allow the coverslip to slide. These cells will show stages in mitosis.
2. In the morning, cut 5 mm from the end of a growing root of onion or pea. Cut the piece of root twice longitudinally. Put the longitudinal sections in a drop of carmine acetic acid on a microscope slide. Cover with a coverslip and heat to boiling point over a small flame by moving the slide backwards and forwards to prevent excessive heating in one place. Put a drop of 2% acetic acid at the side of the coverslip and draw it across under the coverslip with absorbent paper on the opposite side. Press down on the coverslip with a scalpel handle to squash the cells. Examine the cells under high power. Look for dividing nuclei at different stages of development, prophase, metaphase, anaphase and telophase. Count the number of chromosomes, e.g. onion 16 and pea 3. Find the different stages and count the number of each stage. Use this information to estimate the relative lengths of time for each stage during mitosis. The process takes about 2 hours with prophase taking two thirds of the time. Repeat the experiment with root tip specimens taken at different times.
4. The cells of growing and developing organisms are constantly multiplying by cell division. In unicellular organisms daughter cells form which separate after the division process is complete and continue to develop independently. In multicellular organisms the cell mass is increased by cell division. The organisms grow. In cells without a nucleus cell division takes place using a simple constriction process. However, the division process in nucleated cells involves a complicated mechanism of division of the cell nucleus, during which operation the chromosomes are clearly visible and are distributed between the two daughter cells after longitudinal splitting. This process is called indirect nuclear division or mitosis. Observe the different phases of indirect nuclear division, mitosis. Cut 5 mm from the end of a well developed onion bulb root and cut it through longitudinally, twice if possible. Put the longitudinal sections in a large drop of carmine acetic acid on a microscope slide. Cover with a cover slip and heat to boiling point over a small Bunsen burner flame. The slide should be moved gently backwards and forwards over the flame to prevent the glass cracking from excessive heating in one place. The preparation should not be allowed to dry out, so if necessary add a little more carmine acetic acid. Now put a drop of 2% acetic acid alongside the cover slip and draw it across under the coverslip by placing the edge of a filter paper strip at the opposite side of the cover slip. Press down several times on the cover slip with the handle of the dissecting needle so that the cells in the longitudinal sections of the root tip are squashed then examine the preparation under high power. If the tip of the root has been taken at a favourable time, the preparation will contain many dividing nuclei at all stages of development. Draw the different phases of indirect nuclear division, mitosis, and arrange them in order of occurrence. Note to maximize the probability of obtaining all phases of nuclear division, it is recommended that several root tip specimens be taken at different times, especially early in the morning.

9.9.8a Meiosis in grasshopper testes
See diagram.9.108.1: Meiosis 1 | See diagram 9.108.2: Meiosis 2 | See diagram 9.108.3: Meiosis models A | See diagram 9.108.4: Meiosis models B | See diagram 9.108.5 Meiosis models C
Meiosis can be seen in grasshopper testes or in Ascaris where the eggs remain dormant until fertilized. During fertilization the male and female gametes fuse to form a zygote so the number of chromosomes doubles, n chromosomes from the male gamete and n chromosomes from the female gamete. The 2n cells in the sex organs undergo meiosis to halve the number of chromosomes to n chromosomes in the male gamete or female gamete.
Prophase I Leptotene: The chromosomes appear like a long string with of beads, called chromomeres.
Prophase I Zygotene: The homologous chromosomes from the male and female gametes lie closely alongside each other forming shorter and thicker paired structures so appearing to halve the number of chromosomes. They are attached to the inside wall of the nucleus in animals but form a tangled heap in plants.
Prophase I Pachytene: When the pairing complete and the chromosomes appear as "thick" strings. The two chromosomes are referred to as a "bivalent," while the same structure viewed as four chromatids is known as a "tetrad."
Prophase I Diplotene: Each chromosome of a pair splits into two chromatids along their length except at the centromeres. As the chromosomes separate they remain attached at chiasmata where recombination of the genes occurs.
Prophase I Diakinesis: The homologous chromosomes repel each other and continue contracting. The nucleolus and nuclear membrane disappear.
Metaphase I: The bipolar spindle appears and the paired chromosomes (tetrads) line up on the metaphase plate and attach to the spindle fibres with the centromeres.
Anaphase I: Each homologue moves toward opposite poles so halving the number of chromosomes. This process is the reduction division that characterizes meiosis.
Telophase I: The chromosomes may become surrounded by a nuclear membrane but usually the second division starts when the chromatids of each chromosome separate and move to the opposite pole of the spindle.
Second division: This division is similar to normal mitosis except that the number of chromosomes is n not 2n. The four n nuclei develop nuclear membranes during the telophase of the second division to produce a tetrad of pollen grains but only one n nucleus develops in the ovule.

9.9.9 Development of plant embryo
The plant embryo develops from the fertilized ovule of the egg cell as the result of numerous cell divisions. During this process it passes through various stages of development, from the scarcely differentiated state with a small number of cells to the form where the cotyledons and the roots are clearly distinguishable. Investigate the development of embryos of shepherd's purse Capsella bursa-pastoris. Use forceps and a dissecting needle to open carpels of shepherd's purse taken at different ages and remove several ovules. Put a drop of 5% potassium hydroxide solution on a slide using a glass rod, put the ovules in the drop and put a cover slipover them. The tissue of the ovules is disintegrated, disaggregated, to some extent by the potassium hydroxide. Press down on the cover slip with the handle of the dissecting needle to squeeze the embryos out of the ovules. Do this operation with the utmost care to avoid crushing the embryos. Press down several times and check through the microscope after each application of pressure. Examine the preparation under 50 x, objective 10 x, eyepiece 5 x, and then under 200 x, objective 40 x, eyepiece 5 x, microscopic magnification. If, by luck, ovules of differing ages were transferred to the slide, embryos in almost all stages of development will be present. Draw embryos in different stages of development and arrange them according to age.

9.9.10 Growing plant embryos
As there are often considerable differences in the time for development between embryos of the same age, grow many more than you need for the experiment. Put the seeds in a flat glass dish, add water, and allow the seeds to swell. For embryos in an early stage of development, put the swollen seeds in a flat glass dish on moist absorbent paper and leave until the desired stage has been reached. For seedlings of a greater, put the swollen seeds in a flowerpot filled with sawdust or sand. Stand the pot in one half of a flat glass dish and water regularly. For erect seedlings, rotate the flowerpot occasionally so that all seedlings get an equivalent amount of light, or use a clinostat. When the plants have reached the desired stage of growth, remove them from the sawdust and rinse under water.

9.9.11 Germination from seed to plant
See diagram 4.12.2 | See diagram 6.9: Measurement of plant growth
Every spring and summer seeds that have been sown in flowerpots or in the garden or field germinate and give rise to new plants. Study the growth of a plant from a seed. Put 10 bean seeds in an open 100 mm diameter flat glass dish and cover the seeds completely with water. How have they changed by the following day? Describe their condition. You would describe them as swollen. Now fill a glass tank with garden soil up to 2 cm from the top and sow the swollen bean seeds in it. The seeds should be fairly evenly distributed along the four sides of the tank and quite close to the glass so that they can be seen through the glass walls. Put black cardboard, e.g. an old exercise book cover, all round the tank and up to the level of the soil and secure with a rubber band. Water regularly and note daily how the bean seeds continue to develop. You must remove the cardboard to see what is happening in the soil, but remember to put the cardboard back after every observation.
Note the following:
1. How long it takes for the seeds to germinate.
2. In what direction the beanstalk grows.
3. In what direction the roots grow.
4. The first leaves on the stalk, the very thick seed leaves or cotyledons.
5. How do the seed leaves change in time.
6. When the next leaves appear and how do they look compared to the seed leaves
7. The changes in the root and the purpose they serve.
8. The daily growth of a bean plant. Attach a strip of graph paper to a wood splint and place next to one of the bean plants just as it comes out of the soil and begins to sprout. Mark the height of the bean plant on the graph paper every day at the same time.

9.9.12 Function of cotyledons
Place six similar bean seedlings on which sprouting primary leaves are just emerging, in test-tubes so that the roots are immersed completely in water. Hold the seedlings in place with cotton wool plugs, but the water must not contact the cotton wool. Keep two seedlings with both cotyledons. Remove one cotyledon from each of two other seedlings, and remove both cotyledons from the last two seedlings. After two weeks compare the growth of the bean plants. The plants with both cotyledons have developed best, and those without cotyledons have developed worst. Note that the cotyledons which were not cut off have shrivelled. When you remove a cotyledon the seedling gets less nutrients and it may starve.

9.9.13 Natural growth inhibitors
See diagram 4.12.13
1. The formation of growth inhibitors in the immediate vicinity of the embryos, e.g. in the endosperm, in the seed coats, in the pulp, may prevent the premature germination of seeds. Put seeds of cress, garden cress, Lepidium sativum, in a Petri dish with water for ten minutes and allow them to swell.
Put absorbent paper moistened with water in 4 Petri dishes and add the following:
Dish 1: a thin slice of apple,
Dish 2: a thin slice of orange,
Dish 3: a thin slice of tomato,
Dish 4 : absorbent paper only (control).
2. Put ten swollen cress seeds on each of the fruit slices and also on the filter paper in the Dish 4, the control. Put lids on the dishes and leave at room temperature After 48 hours the cress seeds laid on the slices of fruit have hardly altered. However, the seeds on the filter paper in the control dish have germinated. They have grown a small root 10 - 20 mm long. In most instances the first tiny leaves can also be seen. The flesh of apple, tomato and orange all contain growth inhibitory substances. To ensure germination, seed must be separated from the old surrounding fruit tissue.

9.9.14 Zone of elongation of growing root
The increase in root length results from growth occurring a small zone, the extension zone, which is situated just behind the tip of the root. It is only a few millimetres long and usually ends just where the root hairs begin Use four bean seedlings having straight roots 3 cm long, and apply, with a fine hair brush, 15 to 20 horizontal ink lines, each 1 mm apart, on the root, starting immediately behind the tip. A glass container is filled to a depth of 2 cm with water. The bean seedlings are placed on the cork disc, with 7 holes in it, the roots are stuck through the holes, and, with help, the disc is hung from the hooks in the glass container and the glass plate is placed on top. So that the roots will continue to grow, as far as possible, under normal light conditions, a blackout cover is placed over the glass container After 24 hours a marked increase in root length can be seen. The ink lines have been pulled different distances. The lines at the bottom, immediately behind the tip of the root, have not parted very much, the following lines have a much greater distance between them. The top lines are closer still and may not have moved at all. When the roots grow, the ink marks are pulled apart, the distance corresponding to the amount of extension growth in that particular root section

9.9.16 Germination and early development of a bean plant
See diagram 9.1251.
Soak seeds in water, remove the seed coats and examine the internal parts. Endospermic seeds have food stored in a separate endosperm tissue, e.g. castor oil, pine, wheat, barley, maize (corn), coconut, date, lupin, coffee. Non-endospermic seeds have food stored in the cotyledons, e.g. peas, beans, pumpkin, sunflower, peanut, apple.

9.9.17 Grow plants in the classroom without soil
See diagram 9.9: Growing plants without soil
Put a potato, sweet potato, arrowhead vine, and tops of carrot, beet, turnip, pineapple in a container and keep the lower third covered with water or mineral water. Press toothpicks or matches into the sides to rest the plant parts on the rim of the container. The tops produce foliage but not new plants.

9.9.18 Soil-less culture (hydroponics), culture solutions (Knop's solution)
1. Hydroponics means growing plants without soil. The technology of culture with hydroponics is to use chemical culture solution that includes contain elements essential for plants. It is mainly used in vegetables, flowers and plants and tree seedlings. It is used to beautify the environment and home. You can plant with hydroponics in places, e.g. desert, city roof and balcony. Then you can provide nutrient elements according to what the plant is essential. Water is used in a circle, so it saves fertilizer and water. If houses and classroom use hydroponics culture to plant tomato, cucumber, strawberry, rape, romaine lettuce and ornamental plants, it may improve environment and can be eaten.
2. Prepare a series of plastic troughs in which root systems can grow. Line the interfaces of the trough's both ends plastic cement to avoid leaks or use black plastic to avoid being corroded by culture solution and secretion of root system. Grow two plants in a cola glass wrapped in shading material. To cultivate small sized vegetables put culture tanks on the windowsill or assemble hanging models. To link plastic trough and metal net or stand with bolts and fixed articulates. According to the variety of vegetables and the size of plant regulate the distance between every layer trough. The end of the plastic trough inclines faintly and slopes criss-cross between every layer trough. The lower end has the drain hole to drop culture solution, or divert through the thin plastic pipes, into the next layer trough. In the end, culture solution is dropped can be used repeatedly when the plastic bucket is retrieved. You can invert over the highest trough a plastic flat bucket whose capacity is 5 to 7 litres. The outside is packed with black paper or is painted by black and white to cover the light. To control the velocity at which culture solution moves into the upper trough with the thin pipes and the regulating knob. The advantage of the way of the stereoscopic culture is that it does not take up much land to use space enough, after vegetables grow, it may keep out the burning sun in the summer. So the plant can give out oxygen to purify the air in the day and let off carbon dioxide to reduce the respiratory consumption in the night. You can open the window when the temperature is not low, and because this way need not be controlled by electrical machinery and water pumps, managing it is easy.
3. Knop's solution
One of the first culture solutions containing the elements hydrogen, oxygen, calcium, nitrogen, magnesium, sulfur, potassium, phosphorus, iron and chlorine was proposed by W. Knop in 1865. Most plants can grow in that solution and remain healthy.
Ten elements are essential for the growth of a green plant: carbon 3. hydrogen (H) oxygen (O) nitrogen (N) sulfur (S) phosphorus (P) potassium (K) calcium (Ca) magnesium (Mg) and iron (Fe). Plants take in carbon as carbon dioxide from the air and hydrogen and oxygen from H₂O, the water in the soil and air. Plants absorb other elements with the soil water as salts.
Make Knop's solution with 0.8 g of calcium nitrate, 0.2 g of magnesium sulfate, 0.2 g of acid potassium phosphate, 0.2 g of potassium nitrate, 3 drops of ferric chloride solution dissolved in one litre of demineralized or deionized water. Make the following variations of Knop's solution:
3.1 Knop's solution omitting nitrogen: calcium sulfate instead of calcium nitrate, potassium sulfate instead of potassium nitrate
3.2 Knop's solution omitting phosphorus: omit potassium phosphate
3.3 Knop's solution omitting potassium, sodium phosphate instead of potassium phosphate, sodium nitrate instead of potassium nitrate
3.4 Knop's solution omitting calcium: sodium nitrate instead of calcium nitrate
3.5 Knop's solution omitting magnesium, sodium sulfate instead of magnesium sulfate
3.6 Knop's solution omitting iron: omit the ferric chloride
3.7 Knop's solution thus omitting sulfur: magnesium nitrate instead of magnesium sulfate
3.8 Knop's solution: control
Use 1 litre containers fitted with waxed corks bored with holes to take the plants. Fix seedlings into the corks with cotton wool, e.g. barley, wheat, broad bean. Wrap the glass jars with black paper to exclude the light. Label the jars and record the growth and appearance of the plants.
4. Prepare three containers to hold the following solutions:
4.1 aerated deionized water,
4.2 good garden soil and aerated deionized water,
4.3 aerated deionized water and two measures of calcium nitrate, one measure each of potassium nitrate, monobasic potassium phosphate and magnesium sulfate, and a trace of iron (II) sulfate.
Plant 50 maize grains in a large pot containing old sawdust. When the maize plants are 3 cm high, select 21 plants of equal size and wash their roots. Punch seven holes in each of three cork discs. Insert seven maize plants in each of the holes so that their roots hang down below the holes. Put a cork disc with attached plants in each container. After two weeks, note any difference in development of the maize plants. The plants in 4.1 do not grow well, but the plants in 4.2 and 4.3 grow well. Compare the growth of plants in 4.2 and 4.3.

9.9.19 Mineral deficiency experiment
To make four kinds of culture solutions based on large elements, trace elements and iron solution. Among them, the mother solution of the trace elements and iron solution may be kept in the refrigerator. The major elements are compounded in two kinds of reserve solutions (A and B).
The table of the prescription of reserve solution, unit: gram / litre water

Solution	Chemical Name	Molecular Formula	Volume, g / l
Solution A (major elements)	calcium nitrate crystals	Ca(NO₃)₂.4H₂O	30
"	potassium nitrate (nitrate of potash)	KNO₃	-
Solution B (major elements)	ammonium phosphate (di-ammonium hydrogen phosphate)	(NH₄)₂HPO₄	25
-	magnesium sulfate (Epsom salts)	MgSO₄.7H₂O	25
Solution C (iron solution)	EDTA, disodium salt (disodium ethylene diamine)	EDTA-Na₂	2.682
-	ferrous sulfate (iron (II) sulfate-7-water)	FeSO₄.7H₂O	-
Solution D (trace elements)	boric acid (boracic acid)	H₃BO₃	2.86
-	zinc chloride	ZnCl₂	0.22
-	copper (II) sulfate crystals	CuSO₄.5H₂O	0.08
-	molybdic acid	H₂MoO₄	0.02
-	manganese chloride	MnCl₂	0.08

Dissolve EDTA disodium salt in hot water, then add iron (II) sulfate-7-water and mix while it is hot. Do not mix the Solutions A and B to avoid precipitating calcium sulfate. Keep Solutions A and B in a shaded place. Keep Solutions C and D in the refrigerator. In Solution A the proportion of calcium nitrate and potassium nitrate can be adjusted depending on the water quantity and the variety of plants at the place in the locality. For example if hardness of water is great reduce the quantity of calcium nitrate. Make up the solutions with deionized water and regulate pH to 5.5 to 5.8 with HNO₃ or KOH according to the needs of different vegetables, e.g. if the leaf should has the high content of nitrogen increase the content of phosphorus and potassium after the flowering phase.