111 Student?s Name ___________________________Date Performed __________ Course/Year/Section _______________________Date Submitted __________ Professor?s Name___________________ WORKSHEET # 12 FLOWERS I. Basic parts of a flower: (Hibiscus sp.) 1. Dissect the gumamela flower and label the enclosed drawing. 2. Draw and label the cross sections of the lily ovary and anther. Lily Ovary Lily Anther II. Flower Types: Specimens Complete/ Incomplete Nature of Corolla Perfect/ Imperfect Symmetry Ovary Position Inflores- cence 112 III. Composites and Grasses: A. Composites B. Grasses Questions: 1. Name some plants whose flowers are considered vegetables. 2. List plants whose flowers have leaf modifications. For example, the Anthurium has a modified leaf called spathe. 3. Why is the flower usually called "a leaf in love"? Explain your answer. 113 EXERCISE 13 POLLEN and OVULE 114 I. Introduction The essential parts of the flowers are the parts that produce the reproductive structures. Stamens produce the pollen grains or male gametophytes. A group of stamens is called the androecium of the flower. Carpels form the ovule or the female gametophye. A group of carpel is called the gynoecium of the flower. II. Objectives At the end of the exercise, you will be able to 1. describe the parts of the pollen grains and the ovule 2. identify the stages leading to double fertilization in flowering plants III. Materials Equipment/other materials Dissecting microscope glass slides cover slips Plant materials Various flowers Prepared slides of the lily ovary and anther Solutions 10% glucose IV. Procedure A. Pollen Stamens are composed of the anther where pollen grains are produced and the filament that is the stalk of the anther. The number of stamens in a flower depends on the species. Sometimes, the filaments are attached to the petals; sometimes they are free. In the anther, there are several chambers or locules and in the locules, the sporogenous tissue undergoes meiosis and eventually form the pollen grain. In mature anthers, the tapetum layer can be distinguished. The pollen grains may be solitary or united in groups. The outer coat of the pollen is called exine while the inner layer is called the intine. The pollen grain, when it germinates develops the tube nucleus where two sperm nuclei pass through to fertilize the egg. 1. Obtain several stamens of different flowers. Fill the table on the worksheet. 115 2. Take pollen grains from these fresh flowers and observe them under the microscope. Answer the questions on the worksheet. 3. Place mature pollen grains on a slide and add a drop of 10% glucose solution and let it stand for fifteen minutes. Observe the pollen grains and look for the signs of germination. Record your observations on the worksheet. 4. Obtain a prepared slide of the cross section of the anther. Answer the qeustions on the worksheet. B. Ovules The ovules are found in the locules in the ovary. An ovule is attached to the ovary wall by the funiculus. A placenta is the area where the funiculus joins the ovary wall. The central portion of the ovule is the megasporangium or nucellus. The megasporocyte appears as a large cell with a large nucleus. It is normally found towards the apex of the nucellus but not superficially. In more mature ovules, there are one or two folds surrounding the nucellus. These are the integuments. the large cell in the nucellus is the megaspore nucleus that will undergo a series of divisions until the 8-nucleate embryo sac or megagametophyte is formed. The eight nuclei in the megagametophyte contain the 3 antipodals, 2 polar bodies, 2 synergids and the egg nucleus. 1. Make a longitudinal section of the ovary of a fresh flower. Observe the number of ovules in the locules and their arrangement. Identify the funiculus and the placenta. Make a sketch of the longitudinal section of the flower and label the parts in your worksheet. 2. Obtain a slide of the cross section of the ovary. Identify the parts and answer the questions in the worksheet. 3. Obtain a slide of an ovule. Identify the integuments (if present), the megaspore or the megagametophyte and the parts listed above. Answer the questions on your worksheet. Reference Brother Eduardo Salgado. 1994. Handouts in Botany. Department of Biology. De La Salle University. Manila. (unpublished). 116 Student?s Name ___________________________Date Performed __________ Course/Year/Section _______________________Date Submitted __________ Professor?s Name___________________ WORKSHEET # 13 POLLEN AND OVULE A. The Pollen grains Specimen Filaments: free or attached Anthers: no. of locules Pollen grains: solitary or in groups 1. What is the function of the tapetum layer? 2. Draw the pollen grains that you see. Do they all look the same? Why or why not? 3. About how many pollen grains have germinated? In some germinating pollen grains notice the pollen tube. Can you see the nuclei in the tube? 4. Some pollen grains will not germinate in vitro. They will germinate only on compatible stigma. Can you explain why? 5. Draw and label parts of the cross section of an anther. 117 B. Ovule 1. Draw the longitudinal section of an ovary. Label the parts. 2. What type of placentation is present? 3. Draw and label the parts of an ovule. 4. In the flowering plants, the megagametophyte and the microgametophyte are totally dependent on the sporophyte. What advantages do this arrangement provide? 118 EXERCISE 14 FRUITS I. Introduction The flower, as the sexual organ, provides ways to ensure the pollination and fertilization of the egg. Dramatic changes in the flower occur after the union of gametes. The fertilization of the egg results in the embryonic plant. The ovule stores food for the embryonic plant and becomes the seed. An ovary becomes mature and changes to the fruit. The fruits develop mechanisms to facilitate seed dispersal. That is why only plants with flowers develop fruit structures. Sometimes, fruits develop from accessory structures of the flower. In others, fruits are formed without seeds because of the absence of fertilization. II. Objectives At the end of this exercise, you can 1. classify different kinds of fruits 2. identify fruit adaptations for seed dispersal III. Materials Various types of fruits IV. Procedure I. Classification of fruits Fruits are very variable. In some, the fruit wall or pericarp is very thick and can be differentiated into three layers. These are the exocarp (outer layer), the mesocarp (the middle layer) and the endocarp (inner layer.) In some fruits, the pericarp is very thin. Fruits can be classified as to origin. 1. Simple fruits - derived from one ovary of one flower 2. Aggregate fruits - derived from several ovaries of one flower 3. Multiple fruits - derived from a cluster of several ovaries from several flowers crowded together on one stem Fruits can also be classified based on pericarp texture. There are two basic kinds: fleshy pericarps and dry pericarps. Fruits with fleshy pericarp can be further classified into: 1. Berry - the pericarp is fleshy throughout 2. Pepo - a type of berry with hard rind 3. Hesperidium - a type of berry with leathery rind 4. Drupe - one-seeded fruit with the pericarp distinctly divided into thin skin-like exocarp, thick fleshy mesocarp and hard, stony endocarp 5. Pome - fruit with papery pericarp Fruits with dry pericarp can either be dehiscent or indehiscent. Dehiscent fruits split open along definite seams when matured and may contain several or many seeds. There are several types of dehiscent fruits: 1. Legume/pod - has one carpel and splits along two seams 2. Follicle - has one carpel and splits along one seam 3. Capsule - fruit of two or more united carpels and splits in a variety of ways 4. Silique - fruit of two fused carpels that separate, leaving a persistent wall between them Indehiscent fruits do not open along definite seams or points when mature. These 119 usually contain only one or two seeds. Some types of indehiscent fruits are: 1. Achene - one seed can be separated from the ovary wall except at point of attachment to the inside of the pericarp 2. Grain - one seeded the coat of which is completely fused to the inner surface of the pericarp 3. Samara - an achene-like fruit with wing- like outgrowth 4. Nut - one seeded fruit similar to achene but with a very hard and thick pericarp Some fruits may develop from floral parts other than the ovary. These parts are often fused to the ovary and are so well developed that they constitute the major part of the fruit. Classify the fruits and fill the table in the worksheet. II. Mechanisms of seed dispersal Fruits have various ways of dispersing the seed. Fruits are edible, are sticky, have hooks or are attractive to animals so that seeds can be dispersed. Some fruits are also light in weight, have wings, buoyant in water, or impermeable to water, to ease dispersal by wind or water. Some fruits have mechanical ways of seed dispersal like exploding when dry so that seeds are thrown several distances from the main plant. Seeds also exhibit adaptations to facilitate their spread away from the main plant. In the worksheet, identify dispersal mechanisms of the fruits provided. Reference Biology 11 Laboratory Manual For Teaching Assistants. 1989. University of North Carolina. pp. v17-v19. 120 Student?s Name ___________________________Date Performed __________ Course/Year/Section _______________________Date Submitted __________ Professor?s Name___________________ WORKSHEET # 14 FRUITS I. Classification of fruits Specimen Nature of pericarp Type of fruit origin Placentation type Edible part of fruit II. Mechanisms of seed dispersal Specimen Mechanism for dispersal Agent of dispersal 121 Questions: 1. Can you predict the type of placentation a certain fruit will have if you can see only the flower? Why or why not? 2. Drupes are also called stone fruits. Can you explain why? 3. Some commonly called "nuts" are not botanically nuts. Can you give some examples? 4. Why are some fruits also called vegetables? 5. TRUE OR FALSE: a. A peanut is a nut. b. All legumes readily split open at maturity. c. A true nut has a thick, stony pericarp. d. Animal dispersed fruits are necessarily colorful and attractive. e. A strawberry is a berry. f. Walnuts, pili nuts and almonds are drupes. g. An apple is an accessory fruit. h. The edible part of a coconut is the seed. i. A grain and an achene are approximately the same in their make up. j. Winged fruits are dispersed by animals. 122 EXERCISE 15 SEEDS I. Introduction The seed develops from the ovule after fertilization. A mature seed consists of a seed coat, an embryonic plant and a nutrient reserve. This nutrient reserve or food may be stored outside the embryo as endosperm (like in corn) or be absorbed by the developing embryo into large fleshy cotyledons (like the bean). Based on the presence or absence of endosperm as a nutritive storage reserve, there are two types of seeds: the endospermous or albuminous seed and the exendospermous or exalbuminous seed. II. Objectives At the end of this exercise, you will be able to 1. identify the parts of a seed. 2. distinguish the different types of seeds 3. determine how some seeds are dispersed III. Materials Plant materials Soaked Phaseolus sp. (bean) seeds Soaked Zea (corn) seeds Different types of seeds of the following specimens: rice, chico, avocado, atis, tomato, ipil-ipil, mango, orchid, coconut and atsuete. Reagent and other materials IKI Solution Razor blade IV. Procedure I. Parts of a seed A. The bean seed The bean seed is essentially without endosperm at maturity. The bean pod in which this seed was produced is the fruit of the bean plant. The outer covering of the seed is the seed coat. The small elliptical scar along the concave edge of the seed is the hilum which marks the point of attachment of the young seed to the ovary. A small hole at the end of the hilum is the micropyle. At the other end of the hilum is the raphe, a small groove extending to the chalaza, the point at which the integuments were attached to the ovule. The structure found within the seed coat is the embryo. The two fleshy structures which constitute most of the volume of the seed are the coytledons of the embryo. The embryo is attached at one end of the fleshy cotyledons. This embryo is a miniature plant made up of two miniature leaves and a small axis. The tiny leaves represent the epicotyl of the embryo and the little axis, the hypocotyl. Examine a soaked bean seed. Draw the exterior parts. Remove the seed coat and gently split open the seed. Draw the interior parts of the bean seed on the worksheet. Label the coat, micropyle, hilum, cotyledon, embryo, epicotyl and hypocotyl on your drawings. B. The corn seed The corn differs from the bean seed in a number of ways. The external covering of a corn grain is actually the wall of the ovary, or the pericarp so that a corn "seed" is actually a fruit also. The bulk of the interior tissue is endosperm. The small embryo and single cotyledon are situated diagonally at the narrow end of the grain. The cotyledon in corns is also known as scutellum and is not as developed as in beans. The radicle of the seed is covered by the coleorhiza while the epicotyl is covered by the coleoptile. In corn and other monocots, the cotyledon has been reduced to a small 123 mass of tissue which never assumes the shape or function of a photosynthetic leaf on the developing seedling, as dicot cotyledons do, but instead simply absorbs nutrients from the endosperm. Secure a corn seed and carefully split it longitudinally. Stain with iodine solution. Draw the corn seed and identify the pericarp, endosperm, cotyledon, and embryo including the coleorhiza and coleoptile. Label your drawings. II. Classification of seeds Seeds vary in shape, sizes, color, texture and presence or absence of endosperm. The seed is specific to each species such that sometimes seed identification is crucial to species identification. Examine different types of seed and fill up the table on the worksheet. III. Seed dispersal mechanisms Angiospems have evolved many different adaptations for seed dispersal involving various agents. These agents include wind, water and animals. Adaptations to wind dispersal include very minute seeds that are easily carried by wind. Adaptations to water dispersal are seeds that float or fruits that float and thereby carry the seeds with them. Some seeds are useful as a food source to animals which bury the seeds in the ground, where they later germinate if they are forgotten by the foraging animal. Other plants produce a fleshy fruit which is eaten by animals. Another adaptation for animal dispersal is the development of barbed fruits or seeds that stick to the coats or skin of wandering animals. Examine the different types of seeds and fill up the table on the worksheet. Reference Balbach, M. and L.C. Bliss, 1991. A Laboratory Manual for Botany. Saunders College Publishing. Orlando, Florida. pp. 13-19. 124 Student?s Name ___________________________Date Performed __________ Course/Year/Section _______________________Date Submitted __________ Professor?s Name___________________ WORKSHEET # 15 SEEDS I. Parts of a seed A. Bean seed B. Corn seed II. Classification of seeds Specimen No. of cotyledons Endosperm (presence or absence) 125 III. Seed dispersal mechanisms Specimen Mechanism of dispersal or adaptation of seed Agent of dispersal Questions: 1. Explain the statement: ?A seed is a baby plant in a box with its own lunch.? 2. Do all dicot seeds have endosperm? Explain your answer. 126 EXERCISE 16 TRANSPIRATION AND WATER CONDUCTION I. Introduction Transpiration is the loss of water vapor from leaves of plants through the stomata . It is necessary because it is the mechanism by which water and the dissolved solutes are transported to all parts of the plant. It is also unavoidable in the sense that the leaves must have gas exchange with the environment in order to acquire carbon dioxide for photosynthesis. II. Objectives At the end of the exercise, we will be able to: 1. determine the effects of some physical factors on the transpiration rate 2. identify some morphological characteristics that can affect transpiration rate. 3. examine variations in stomatal appearance and distribution in different plant species in campus. III. Materials Equipment/Apparatus: improvised potometer set-up: iron stand, clamps, rubber tubing electric fan light meter lamp Solutions: 0.01% eosin boiled and cooled distilled water Glasswares: biuret 2 (100-ml) beakers petri dish large transparent glass jar Specimens: Coleus blumei (mayana) Muntingia calabura (datiles) Oryza sativa (rice) seedlings Other Materials: ruler cobalt chloride paper Duco cement / colorless nail polish sharp blade rubber band black plastic bag IV. Procedure A. Effect of Some Environmental Factors on Transpiration Rate A.1. Use of an Improvised Potometer The class is divided into groups 1 - 4. All groups will use both Coleus (mayana) and Muntingia (datiles). 1. Cut a leafy branch with 3 nodes from each plant species. As much as possible, do the cutting under water and as quickly as possible. Hold the branch under water again and cut off about 2 cm of stem from the base of the shoot. 2. Transfer the shoot to a large beaker of tap water, making sure a drop of water adheres to the basal cut surface. This prevents entry of air into the base of the stem. 3. Assemble the improvised potometer set-up shown in Figure 1. Insert a rubber tubing into the delivery end of 127 the biuret. Make sure the fitting is tight. 4. Fill the biuret completely, including delivery tip with freshly boiled and cooled distilled water as well as the rubber tubing with same water, making sure all trapped air bubbles are dislodged. Make sure the fitting is tight. 5. Insert the shoot with a drop of water on the base to the other end of the rubber tubing, excluding all air from the system. The entire system must be completely filled with water. Tie a rubber band around the rubber tubing at the plant end to close the set-up. There is the tendency for water to flow out of the rubber tubing while inserting the shoot. 6. Support the shoot with a biuret clamp. Check the system for leaks. Do this by closing the stopcock end while gently squeezing the rubber tubing. 7. Determine the transpiration rate in light and still air, light with fanning, dark and still air and dark with fanning. The dark condition was imposed by placing a black plastic bag over the shoot. 8. Measure light intensity with light meter. 9. After 2 hours, take note of the amount of water transpired. Determine the rate of water transpired. Tabulate the results of your group as well as those of the other groups in Table 1. A.2. Use of Cobalt Chloride Paper Another method of measuring the transpiration rate is using cobalt chloride paper. This paper is impregnated with cobalt chloride and it is blue when dry and pink when moist. The time it takes for the blue cobalt chloride paper to change to standard pink coloration when the paper is held against a leaf surface can be taken as a comparative measure of transpiration rate. 1. Your group will be assigned a place in the campus where you will select plants to work on. Select 5 plants that are growing under the sun and 5 plants growing under the shade. 2. Before going out into the field, get the prepared cobalt chloride paper from the stockroom (J304). Do not touch the strips of cobalt-chloride papers with finger. The strips have been covered with a sheet of clear plastic. 3. Fasten identical pieces of dry cobalt paper on both leaf surfaces of each selected plant. Hold the strips and the plastic cover in place with paper clips. Be sure the leaf is dry. No film of water must be present on the surface of leaf when you attach the cobalt chloride paper. Write your results in Table 2. 4. Get a leaf from each of the plant species that you have just examined. 5. In the laboratory, spread a small amount of duco cement on the lower leaf surface of each plant. Let dry. 6. Strip a small piece of epidermis and observe under the microscope. Make sketches on the appearance and distribution of stomata, and size of aperture. 7. Describe your observations. B. Rise of the Transpiration Stream Each group will compare ascent of water in herbaceous and woody plants. For herbaceous plants, use Coleus and for woody plants, Muntingia. 1. Secure an 18 cm leafy stem of both Coleus and Muntingia under water and quickly immerse in 100- ml beaker containing 5 ml of 0.01% eosin. 128 2. After 30 minutes, carefully split one stem longitudinally and measure the distance travelled by the dye. Compare the two plant species. 3. Cut also a thin cross section of the stem with a razor blade and examine the location of the dye in the section. Make a sketch of the x- section. C. Guttation 1. Get three 2-week old rice seedlings that have been germinated in a petri dish. 2. Put enough water so that the seedlings have plenty of water supply. 3. Place the set-up under lighted condition and cover with a larhe transparent jar. 4. Observe what happens after 24 hours or during the next laboratory period. Note particularly the position of the drips which have formed on the leaves. 5. Record your results on the worksheet. 129 References 1. Barbour, M.G., B.A. Bonner and G.J. Breckon. 1975. Botany. A Laboratory Manual. 5th ed. John Wiley and Sons, Inc. New York. pp. 69- 75. 2. Kaufman, P.B., J. Labavitch, A. Anderson-Prouty and N. Ghosheh. 1975. Laboratory Experiments in Plant Physiology. MacMillan Publishing Co., Inc. New York. Pp. 145-147. 130 Name _____________________________ Date Performed _____________ Year/Section________________________ Date Submitted______________ Instructor___________________________ WORKSHEET # 16 TRANSPIRATION AND WATER CONDUCTION Table 1. Comparison of the transpiration rate of two species using an improvised potometer set-up. Transpiration Rate (vol/unit time) Treatment Coleus Muntingia 1 2 3 4 Ave. 1 2 3 4 Ave. Room condition Outdoor Dark/Still air Table 2. Comparison of the transpiration rate of plants growing under the sun and shade using the cobalt chloride paper. Plants under sun Time it takes for cobalt chloride paper to change color Plants under shade Time it takes for cobalt chloride paper to change color Appearance of the stomata of selected plant species: 131 Questions: 1. Why is cutting of stem under water always done? 2. What are some of the environmental factors which influence the rate of transpiration? 3. What are the pores called through which water escapes from the leaf by guttation? 4. Discuss the advantages and disadvantages of the transpiration process in plants? 5. What strategies have evolved by which plants are able to reduce their transpiration rates and thus conserve water? 132 Table 3. Comparison of water movement during transpiration of Coleus and Muntingia. Plant species Distance travelled by the dye Rate of movement Coleus Muntingia Questions: 1.How fast have the dyes ascended through the stems per minute? 2. In what tissue/s is/are the dyes present? 3. What conclusion on the path of water conduction through stems be derived from this experiment? 133 EXERCISE 17 MINERAL NUTRITION I. Introduction Plants require essential elements for proper growth and development. These elements may be a macronutrient (major element) or a micronutrient (minor element). Macronutrients are elements required in greater amounts. These are carbon, hydrogen, oxygen, nitrogen, phosphorus, potassium, sulfur, calcium, and magnesium. Micronutrients are elements required by the plant in very low concentrations constituting a few parts per million of the dry weight. These are iron, manganese, boron, copper, zinc, chlorine, and molybdenum. Each of these elements perform specific metabolic roles in the life cycle of the plant. How are plants assessed whether they are deficient in certain nutrients or not? One approach is to use hydroponic culture, a soil less method of growing plants which uses solutions of known chemical composition. When an essential element is deficient, plants usually respond by characteristic visual symptoms and stunted growth. Among the symptoms to look for include yellow leaves and their location, dead spots and their location, and other unusual colors. II. Objectives At the end of the exercise, we will be able to: 1. become familiar with a method of growing plants hydroponically. 2. 2. observe deficiency symptoms associated with inadequate supplies of selected essential element. III. Materials Solutions: Prepared Nutrient Media: complete, - N, - P, - K Glasswares/group: 1 (1 liter) cylinder 1 (1 liter) beaker 1 stirring rod 5 (1 liter) jars Plant material: Zea mays (corn) plants, 1 week old Lycopersicon esculentum (tomato), 4 weeks old Other materials: aerator, air stone, plastic wires, masking tape, pentel pen, carbon paper, forceps IV. Procedure 1. Wash each jar with detergent and water. Rinse several times with tap water and finally wash with distilled water. Allow the bottles to drain. 2. Wash also the covers and air stones. 3. Label the jars as follows: complete, - N, - P, - K and distilled water. 4. Prepare the solution in each jar as denoted by the label. The appropriate components are indicated in Table 1. Make to volume with distilled water. Stir thoroughly. Rinse all glasswares used with distilled water before proceeding to mix the next culture solution. Cover each jar with the 134 styrofoam cover. Work as aseptically as possible. 5. Carefully remove 3 (3-week old) corn seedlings from a germination tray, avoiding as much as possible breaking of roots. Remove all clinging debris and rinse the root systems of the seedlings once in tap water and then once in distilled water. 6. Get the initial length of root and shoot and enter data in the data sheet. 7. Using a forcep, carefully bore 3 small holes through the styrofoam cover and place in each hole, one seedling. Hence, there will be 3 seedlings per jar. 8. Support each seedling with cotton around the hypocotyl region. Be careful not to injure the plant. The root system should be freely suspended in the solution. The cotton must not be in contact with the solution. Place the air stone and the aerator. 9. Place all plants in a well-lighted condition during the day. 10. Observe the plants during each laboratory period. Check the level of solution in each jar and replenish the water lost by adding distilled water. 11. After 3 weeks, measure the final length and dry weight of the roots and shoots . Record your results in Table 1. Describe the deficiency symptoms which have developed. 135 Table 1. Composition of nutrient solutions / liter solution1 Stock Solution 1 Complete 2 -N 3 -P 4 -K 5 Distilled H2O 1 M Ca(NO3)2 5 ml - 5 ml 5 ml - 1 M KNO3 5 ml - 5 ml - - 1 M MgSO4 2 ml 2 ml 2 ml 2 ml - 1 M KH2PO4 1 ml 1 ml - - - FeEDTA 2 ml 2 ml 2 ml 2 ml - Micronutrients2 1 ml 1 ml 1 ml 1 ml - 1 M NaNO3 - - - 5 ml - 1 M NaH2PO4 - - - 1 ml - 1 M CaCl2 - 5 ml - - - 1 M KCl - 5 ml 1 ml - - 1Modified from Moore (1974). 2 Micronutrients stock solution (minus iron) contains per liter: 2.86 g H3BO3, 1.81 g MnCL2.4H2O, 0.11 g ZnCl2, 0.05 g CuCl2 . 2H2O and 0.025 g Na2MoO4. 2H20. References 1. Hershey, D.R. 1994. Solution culture hydroponics: history and inexpensive equipment. The American Biology Teacher 56(2):111-118. 2. Moore, T. 1974. Research Experiences in Plant Physiology. A Laboratory Manual Springer ?Verlag. New York. pp.361-365. 3. Ting, I. 1982. Plant Physiology. Addison-Wesley Publishing Company, Inc. USA. pp. 342- 353. 136 Name _____________________________ Date Performed _____________ Year/Section________________________ Date Submitted______________ Instructor___________________________ WORKSHEET # 17 MINERAL NUTRITION Table I. Growth of corn seedlings in different nutrient solutions. Treatments Average initial length (cm) Average final length (cm) Average dry weight (gm) Roots Shoots Roots Shoots Roots Shoots Complete Minus N Minus P Minus K Distilled H2O 2. Visual observation on the various deficiency symptoms: (a) Complete (b) Minus N 137 (c) Minus P (d) Minus K (e) Distilled H2O Questions: 1. What can be deduced from the relative age of organ showing the first sign of deficiency for a given nutrient? 2. Why are dark colored containers preferably used in culture solution studies? 3. Why is it necessary to observe aseptic protocols in this experiment? 4. Give examples of plants that have been grown using hydroponics (not necessarily in the Philippines). 5. Soil-less agriculture is practiced extensively in Israel. Why do you think so? 138 EXERCISE 18 HORMONAL REGULATION OF SOME ASPECTS OF PLANT GROWTH I. Introduction Plant hormones are a group of naturally occurring organic substances, which in small quantities, promote, inhibit or in some other way modify any physiological process. Many of these hormones have been classified on the basis of their chemical structure or the effects they produce. There are five recognized groups of natural plant hormones: auxins, gibberellins, cytokinins, ethylene, and abscisic acid. Similar to animal hormones, the synthesis of plant hormones may be localized but they may occur in a wide range of tissues, or cells within tissues. Nowadays, there are many hormones that are synthesized chemically and can initiate responses similar to those caused by the natural hormones. Hence, the term plant growth regulators have been used to refer to both natural and synthetic plant hormones. II. Objective At the end of the exercise, we will be able to: observe the effects of some plant hormones on certain aspects of growth. III. Materials Solutions: IAA concentrations (mg/l): 0.1,1.0,10.0 Cytokinin (6-Benzylaminopurine):20 mg/l Naphthaleneacetic acid (NAA): 0.1% Gibberellic Acid (GA) concentrations (mg/l): 1.0, 10.0, 100.0 distilled water Specimens: Vigna radiata (mongo) seedlings Bryophyllum pinnata (kataka-taka) Vigna unguiculata (bush sitao) Glasswares: beakers (150-ml) droppers petri dish Other Materials: germinating trays plastic cups markers sharp razor blades cardboard soil sterilized sand ruler lanolin IV. Procedure: A. Role of auxin in root formation 1. Secure 4 (150-ml) beakers and label from T1 - T4. 2. Fill the beakers with 100-ml of the following treatment solutions: * T1 - Distilled water * T2 - 0.1 mg/l IAA * T3 - 1.0 mg/l IAA * T4 - 10.0 mg/l IAA 3. Select 16 mungbean plants with the first pair of leaves fully expanded in a seed box. 4. Cut these plants at soil line or bases of hypocotyls and place them in a beaker of tap water half immersed until all cuttings are made. 5. Prepare a cardboard cover for each of the beaker with 4 small, equally- spaced holes on each cover. 139 6. Insert the de-rooted plantlets through each of the small holes, making sure that at least 2 - 3 cm of the basal end of the plants are immersed in the solution. 7. Leave the set-ups in a well-lighted area of the laboratory. 8. After one week, count the number of cuttings with roots and the number of roots per cutting. Record the results in Table 1. B. Role of auxin and cytokinin in the regulation of bud formation in Bryophyllum 1. Obtain 3 potted plants of Bryophyllum sp. Label each pot A, B and C. 2. For pot A, immerse each leaf in a petri dish containing 20 mg/l 6- benzylaminopurine for 1 min per leaf. 3. For pot B, immerse each leaf in a petri dish containing distilled water for 1 min per leaf. 4. Prepare 2 plastic trays and put sterilized sand in each. Mark these trays +NAA and -NAA. 5. Now, detach 6 mature leaves from pot C and plant 3 leaves in each of the 2 plastic trays, maintaining an angle of 45o as much as possible when planting. 6. Apply 0.1 % NAA in lanolin to notches along leaf margins of (+)NAA-treated leaves, and lanolin alone to margins of (-)NAA-treated leaves. 7. Leave the set-ups in a condition. 8. Water the soil and sand where the plants are growing. Do not water the treated leaves. 9. After 10, 20, and 30 days, record the number of buds formed along leaf margins. Record your data in the worksheet. C. Role of Gibberellin in Stem Elongation 1. Get 4 plastic cups with soil. Bore three small holes at the bottom of each cup. 2. Label each cup as follows: ? DW (distilled water) ? 1.0 mg/l GA ? 10 mg/l GA ? 100 mg/l GA 3. Plant 5 bush sitao seeds in each cup. 4. When the plants are 7-8 cm tall, select 2 plants that are about the same size. 5. Measure the height of each plant from the cotyledons to the tip of the shoot apex at the beginning of the experiment. 6. Then add one drop of the designated concentration of GA solution to the apical meristem of the plants. 7. After one week, remeasure the height of the plants. 8. Record your data in the Table 3 of the worksheet. 140 References 1. Abramoff, P. and R. Thomson. 1991. Laboratory Outlines in Biology V. W.H. Freeman and Company. New York. pp. 269-281. 2. Kaufman, P. B., J. Labavitch, A. Anderson-Prouty and N. Ghosheh. 1975. Laboratory Experiments in Plant Physiology. Macmillan Publishing Co., Inc. New York. pp. 213-216. 3. Sundberg, M. 1995. Instructor?s Resource Manual to Accompany Botany. Saunders College Publishing. USA. pp. 98-105. 141 Name _____________________________ Date Performed _____________ Year/Section________________________ Date Submitted______________ Instructor___________________________ WORKSHEET # 18 HORMONAL REGULATION OF SOME ASPECTS OF PLANT GROWTH A. Role of Auxin in Root Formation Table 1. Effect of auxin on root formation of mungbean seedlings. Treatment Number of cuttings with roots Number of roots per cutting Control (distilled water) 0.1 mg/l IAA 1.0 mg/l IAA 10.0 mg/l IAA Questions: 1. How do you explain the results of the different concentrations of IAA on the rooting response of the mungbean cuttings? 2. What is the practical value of this exercise? 142 B. Role of auxin and cytokinin in the regulation of bud formation in Bryophyllum Table 2. Regulation of bud formation in Bryophyllum by a benzylaminopurine and naphthaleneacetic acid. Treatment Number of buds formed after 10 days 20 days 30 days Average Water-treated leaves BA-treated leaves NAA-treated leaves 1. Explain your results. C. Role of gibberellin in stem elongation Table 3. Role of gibberellin in stem elongation. Concentration of gibberellin Height of plants (cm) Appearance of plants 0 mg/l 1.0 mg/l 10.0 mg/l 100.0 mg/l Questions: 1. Did gibberellic acid have any effect on stem elongation? 2. Did it affect the morphology of the stem and leaves? 143 3. What is the significance of this exercise? 144 EXERCISE 19 TAXONOMIC SURVEY OF THE PLANT AND PLANT-LIKE WORLD Introduction: Organisms with photosynthesizing pigments belong to Kingdom Monera, Protista, Fungi and Plantae. They may however be distinguished from each other mainly based on life forms and history, type of photosynthesizing pigments, chemical components of cell wall, among others. Objectives: At the end of the exercise, we will be able to: 1. To be familiar with the different plants and plant-like species representing different plant or plant-like groups 2. To classify these species according to a general hierarchial classification scheme 3. To differentiate the species and groups according to their distinguishing characteristics 4. To describe the ecological and economic significance of the species and groups Procedure: Examine the different specimens (slides, pickled and dried specimens). Draw and label the parts. Determine the classification (Division, Class, Order). Determine the distinguishing characters of each species or taxon. Determine the economic and ecological importance each group or species. Tabulate these data per species arranged according to a hierarchial classification scheme. The specimens to be examined per group are listed below. Beside each name is a brief description and the essential parts of the species. Cyanobacteria Gloeocapsa Oscillatoria Spirulina Anabaena Nostoc Rivularia Fungi Rhizopus Mucor Saccharomyces Daldinia Claviceps Peziza Polyporus Stemonitis Arcyria Saprolegnia Rhizopus Xylaria Daldinia Cookeina Puccinia 145 Aspergillus Penicillium various pickled and dried specimens Lichens Cladonia Romalina Physcia Parmelia Fruticose Crustose Foliose Protists Euglena Vaucheria Peridinium Ceratium other diatoms Chlorophytes Chlamydomonas Pandorina Volvox Spirogyra Ulothrix Oedogonium Desmids Various pickled and dried specimens Phaeophytes Fucus Laminaria Various pickled and dried specimens Rhodophytes Polysiphonia Various pickled and dried specimens Bryophytes Riccia Marchantia Porella Anthoceros Mnium Sphagnum Various dried specimens Ferns and Fern Allies Lycopodium Selaginella Psilotum Tmesipteris Equisetum Isoetes Salvinia Azolla Various dried specimens Gymnosperms Cycas (male and female) Pinus Various dried specimens Angiosperms Various dried specimens 146 REFERENCES: Abramoff, P. and R. Thomson. 1972. Laboratory Outlines in Biology. W.H. Freeman and Co. San Francisco. Barbour, M.G., B.A. Bonner and G.J. Breckon. 1975. Botany: A Laboratory Manual. 5th edition. John Wiley and Sons, Inc. New York. Balbach, M. and L.C. Bliss. 1991. A Laboratory Manual in Botany. Saunders College Publishing. Becker, W.M., J.B. Reese and M.F. Poenie. 1996. The World of the Cell. The Benjamin/Cummings Publishing Company, Inc. California. Biology 11 Laboratory Manual for Teaching Assistants. 1989. University of North Carolina. U.S.A. Department of Biochemistry. 1978. Experimental Biochemistry. Basic Concepts and Selected Techniques. University of the Philippines College of Medicine. Manila, Philippines. Department of Botany Faculty Staff. 1971. General Botany Laboratory Manual. Department of Botany, University of the Philippines, Diliman. Quezon City. Kaufman, P.B., A. Labavitch, J. Anderson-Prouty and N. Ghosheh. 1975. Laboratory Experiments in Plant Physiology. MacMillan Publishing Co., Inc. New York. Madulid, D.A. 1995. A Pictorial Cyclopedia of Philippine Ornamental Plants. Bookmark Publishing Co. Manila. Moody, K., C.E. Munroe, R.T. Lubigan, and E.C. Poller. 1984. Major Weeds of the Philippines. Weed Society of the Philippines. UPLB, College, Laguna. Moore, R., W.D. Clark, K.R. Stern and D. Vodopich. 1995. Botany. Wm. C. Brown Publishers. Dubuque. IA. Roberts, J. and D.G. Whitehouse. 1976. Practical Plant Physiology. Longman, Inc. New York. Reiss, C. 1994. Experiments in Plant Physiology. Prentice Hall Inc. New Jersey. Sharma, O.P. 1993. Plant Taxonomy. Tata McGraw Hill Publishing Company Ltd. New Delhi. Sudgen A. 1984. Longman Illustrated Dictionary of Botany. Longman York 147 Press. Essex. Sundberg, M. 1991. Instructor?s Resource Manual for Botany: An Introduction to Plant Biology. Saunders College Publishing. Biology Manual May 08.pdf
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