a. is gaseous b. is responsible for phototropism c. induces femaleness in flowers of cucumber d. is used for killing weeds (dicots) e. induces flowering in long-day plants Solution: a. is gaseous:...
3. Name a hormone which
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Plant Growth and Development
2. It is known that some varieties of wheat are sown in autumn but are harvested around next mid-summer.
a. What could be the probable reason for this? b. What term is used for this promotion of flowering under low temperature? c. Which plant hormone can replace the cold treatment? Solution: a) They...
1. Some varieties of wheat are known as spring wheat while others are called winter wheat. The former variety is sown, and planted in spring and is harvested by the end of the same season. However, winter varieties, if planted in spring, fail to flower or produce mature grains within a span of a flowering season. Explain, why?
Solution: They would generally fail to flower or yield ripe grain during a flowering season if planted in the spring, thus they are sown in the autumn. After that, they germinate, and seedlings...
20. Fill in the blanks:
a. Maximum growth is observed in ________ phase. b. Apical dominance is due to ____________ c. ___________ hormone initiate rooting d. Pigment involved in Photoperception in flowering plants is...
19. On germination a seed first produces shoot with leaves, flowers appear later,
a. Why do you think this happens? b. How is this advantageous to the plant? Solution: a. This means that the plant enters the vegetative growth phase. A flowering hormone called florigen is...
18. A gardener finds some broad-leaved dicot weeds growing in his lawns. What can be done to get rid of the weeds efficiently?
Solution: To effectively eliminate weeds, auxins, a plant growth hormone regulator, can be used to selectively destroy them.
17. While eating watermelons, all of us wish it was seedless. As a plant physiologist can you suggest any method by which this can be achieved?
Solution: For this, parthenocarpy might be used. Gibberellins and auxins producing parthenocarpy in tomatoes are examples of growth hormones that can cause parthenocarpy.
16. Define parthenocarpy. Name the plant hormone used to induce parthenocarpy.
Solution: Parthenocarpy is the artificially induced growth of fruit that does not require fertilisation. Gibberellin is a plant hormone that is used to promote parthenocarpy.
15. Both animals and plants grow. Why do we say that growth and differentiation in plants are open and not so in animals? Does this statement hold for sponges also?
Solution: Because the meristematic tissues of the meristems present in various locations of the plant body are an active site of cell division where growth is indefinite, the plant growth and...
14. Label the diagram
a. This is which part of a dicotyledonous plant? b. If we remove part 1 from the plant, what will happen? Solution: a) This is the shoot apex meristem of a dicotyledonous plant. b) The apical bud is...
13. A rubber band stretches and reverts to its original position. Bubble gum stretches, but it would not return to its original position. Is there any difference between the two processes? Discuss it with respect to plant growth (Hint: Elasticity (reversible) Plasticity (irreversible))
Solution: According to physics, if a substance regains its previous shape once deforming forces are removed, the substance is said to exhibit elasticity. Plasticity, on the other hand, is defined as...
12. In a slide showing different types of cells can you identify which type of the cell may be meristematic and the one which is incapable of dividing and how?
Solution: Meristematic cells are identified by the presence of the following characteristics on a slide with different types of cells: (a) A cell wall that is thin.(b) Cytoplasm that is dense(c)...
11. To get carpet-like grass lawns are mowed regularly. Is there any scientific explanation for this?
Solution: The process of Decapitation of plants leads to the inactivation of axillary buds and promotes the growth of lateral buds giving a carpet like an appearance.
10. Many discoveries in science have been accidental. This is true for plant hormones also. Can you justify this statement by giving an example? Also what term is used for such accidental findings?
Solution: When Charles Darwin and his son Francis Darwin observed the coleoptiles of canary grass, they noticed that it responded to unilateral illumination by bending and growing towards the light...
9. In animals, there are special glands secreting hormones, whereas there are no glands in plants. Where are plant hormones formed? How are the hormones translocated to the site of activity?
Solution: Plant hormones can be found in a variety of tissues, including the tips of shoots, the tips of roots, meristematic tissues, and apical buds, among others. The vascular bundle tissues, such...
8. What is the mechanism underlying the phenomenon by which the terminal/apical bud suppresses the growth of lateral buds? Suggest measures to overcome this phenomenon.
Solution: Apical dominance is the mechanism behind the phenomena of the terminal/apical bud suppressing the growth of lateral buds. Decapitation, or the removal of the apical bud (shoot cutting),...
7. While experimentation, why do you think it is difficult to assign any effect seen to any single hormone?
Solution: It's difficult to attribute any effect to a single hormone because it might have both a synergistic and antagonistic effect. The synergistic effect occurs when two hormones interact and...
6. The role of ethylene and abscisic acid is both positive and negative. Justify the statement.
Positive Roles of Ethylene : Negative Role of Ethylene : Positive Role of Abscisic acid: Negative Role of Abscisic acid: Solution: (a) Positive Roles of Ethylene: Ripening of fruits – It stimulates...
5. Auxins are growth hormones capable of promoting cell elongation. They have been used in horticulture to promote growth, flowering and rooting. Explain the meaning of the following terms related to auxins.
a. auxin precursors b. anti-auxins c. synthetic auxins Solution: a. Auxin precursors are responsible for auxin synthesis. b. Anti auxin function as an inhibition of the action of auxin by competing...
4. Explain in 2-3 lines each of the following terms with the help of examples taken from different plant tissues
a. Differentiation b. De-differentiation c. Redifferentiation Solution: a) Differentiation: the cell of the apices of roots, apices of shoot and cambium can differentiate and mature so that they can...
3. Does the growth pattern in plants differ from that in animals? Do all the parts of plant grow indefinitely? If not, name the regions of the plant, which can grow indefinitely.
Solution: Plants do have a different growth pattern than animals. Only meristematic tissues can continue to divide, i.e. meristems are the sections of the plant that continue to grow indefinitely...
2. What are the structural characteristics of a plants tissues? Meristematic cells near root tip b. The cells in the elongation zone of the root
Solution: a) Meristematic cells near the root tip: -large nucleus -rich protoplasm -vacuoles are less in number b) The cells in the elongation zone of the root -more number of vacuoles -new...
1. Nicotiana tabacum, a Short Day Plant, when exposed to more than a critical period of light fails to flower. Explain.
Solution: A short-day plant requires a long period of darkness to flower because the chemical changes that occur during this time flower the plant. As a result, it necessitates a brief daytime...
13. The rice seedlings infected with fungus Gibberella fujikuroi is called foolish seedlings? What was the reason behind it?
Solution: The elongation of internodes is a characteristic of Gibberellin that causes foolish seedling disease in rice.
12. Growth is one of the characteristics of all living organisms? Do unicellular organisms also grow? If so, what are the parameters?
Solution: Yes, Unicellular organisms do, in fact, grow. Growth characteristics include an increase in cell mass and a rise in cell number. It multiplies by dividing its cells or by undergoing cell...
11. In the figure of sigmoid growth curve given below, label segments 1, 2 and 3.
Solution: 1: Lag phase 2: Log phase 3: Stationary phase
10. Light plays an important role in the life of all organisms. Name any three physiological processes in plants which are affected by light.
Solution: a) Photosynthesis: Photosynthesis is the conversion of carbon dioxide into carbohydrates by green plants using light energy. b) Photoperiodism: Flowering is regulated in photoperiodism in...
9. In botanical gardens and tea gardens, gardeners trim the plants regularly so that they remain bushy. Does this practice have any scientific explanation?
Solution: They are eliminating the shoot tips that cause lateral buds to grow. If the tip is not removed, the apical buds impede lateral bud growth.
8. Where are the following hormones synthesized in plants?
a. IAA b. Gibberellins c. Cytokinins Solution; a. IAA: in the tips of the shoot and apical buds b. Gibberellins: in young leaves and tips of roots c. Cytokinins: meristematic zones of the...
7. A farmer grows cucumber plants in his field. He wants to increase the number of female flowers in them. Which plant growth regulator can be applied to achieve this?
Solution: Ethylene (C2H4) is the plant growth regulator that can be applied to achieve this.
6. Classify the following plants into Long-Day Plants (LDP), Short Day Plants (SDP) and Day Neutral Plants (DNP) Xanthium, Henbane (Hyoscyamusniger), Spinach, Rice, Strawberry, Bryophyllum, Sunflower, Tomato, Maize.
Solution: Henbane: Long Day Plant (LDP) Spinach: Long Day Plant (LDP) Rice: Short Day Plant (SDP) Strawberry: Short Day Plant (SDP) Bryophyllum: Long Short Day plant (LSDP) Sunflower: Day Neutral...
5. Gibberellins promote the formation of ______ flowers on genetically ____ plants in Cannabis whereas ethylene promotes formation of _______ flowers on genetically ______ plants.
Solution: Gibberellins promote the formation of male flowers on genetically female plants in Cannabis whereas ethylene promotes formation of female flowers on genetically male plants. GA does not...
4. Gibberellins were first discovered in Japan when rice plants were suffering from balance (the foolish seedling disease) caused by a fungus Gibberellafujikuroi.
a. Give two functions of this phytohormone. b. Which property of Gibberellin caused foolish seedling disease in rice? Solution: a) Gibberellins cause fruits to lengthen and form to improve. It is...
3. A primary root grows from 5 cm to 19 cm in a week. Calculate the growth rate and relative growth rate over the period.
Solution: L1 = L0 + rt 19 – 5 = r x 1 14cm per week Relative growth rate = Change/Initial*100 19-5/5 x 100 = 14/5 x 100 =280%
2. Plant growth substances (PGS) have innumerable practical applications. Name the PGS you should use to
a. Increase the yield of sugar cane. b. Promote lateral shoot growth. c. Cause sprouting of potato tuber. d. Inhibit seed germination. Solution: a. Increase the yield of sugar cane: Gibberellins b....
1. Fill in the places with appropriate word/ words.
a. A phase of growth which is maximum and fastest is __________. b. Apical dominance as expressed in dicotyledonous plants is due to the presence of more ________ in the apical bud than in the...
12. The photoperiod in plants is perceived at
a. Meristem b. Flower c. Floral buds d. Leaves Solution: Option (d) is the answer.
11. Monocarpic plants are those which
a. Bear flowers with one ovary b. Flower once and die c. Bear only one flower d. All of the above Solution: Option (b) is the answer.
10. ABA acts antagonistically to
a. Ethylene b. Cytokinin c. Gibberellic acid d. IAA Solution: Option (c) is the answer.
9. To increase sugar production in sugarcanes, they are sprayed with
a. IAA b. Cytokinin c. Gibberellin d. Ethylene Solution: Option (c) is the answer.
8. Plasticity in plant growth means that
a. Plant roots are extensible b. Plant development is dependent on the environment c. Stems can extend d. None of the aboveSolution: Option (b) is the answer.
7. The term synergistic action of hormones refers to
a. When two hormones act together but bring about the opposite effects. b. When two hormones act together and contribute to the same function. c. When one hormone affects more than one function. d....
6. Growth can be measured in various ways. Which of these can be used as parameters to measure growth
a. Increase in cell number b. Increase in cell size c. Increase in length and weight d. All the above Solution: Option (d) is the answer.
5. Apples are generally wrapped in waxed paper to
a. Prevent sunlight from changing its colour b. Prevent aerobic respiration by checking the entry of O2. c. Prevent ethylene formation due to injury d. Make the apples look attractive Solution:...
4. Match the following:
A. IAA B. ABA C. Ethylene D. GA E. Cytokininsi. Herring sperm DNA ii. Bolting iii. Stomatal closure iv. Weed-free lawns v. Ripening of fruits Options: a A – iv, B – iii, C – v, D – ii, E – i b A –...
3. The effect of apical dominance can be overcome by which of the following
hormone: a. IAA b. Ethylene c. Gibberellin d. Cytokinin Solution: Option (d) is the answer.
2. Coconut water contains
a. ABA b. Auxin c. Cytokinin d. Gibberellin Solution: Option (c) is the answer.
1. Ethylene is used for
a. Retarding ripening of tomatoes b. Hastening of ripening of fruits c. Slowing down the ripening of apples d. Both b and c Solution: Option (b) is the answer.
11. What would be expected to happen if:
(a) GA3 is applied to rice seedlings (b) dividing cells stop differentiating (c) a rotten fruit gets mixed with unripe fruits (d) you forget to add cytokinin to the culture medium Solution: If...
10. Would a defoliated plant respond to photoperiodic cycle? Why?
Solution: No, a plant that has lost its leaves will not respond to the photoperiodic cycle. This is due to the fact that the leaves are the areas where dark or light duration is perceived. Plants...
9. Which one of the plant growth regulators would you use if you are asked to:
(a) induce rooting in a twig (b) quickly ripen a fruit (c) delay leaf senescence (d) induce growth in axillary buds (e) ‘bolt’ a rosette plant (f) induce immediate stomatal closure in leaves...
8. ‘Both a short day plant and a long day plant can produce flower simultaneously in a given place’. Explain.
Solution: Flowering of a few plants is influenced by the lengths of dark and light intervals. Both long-day and short-day plants can flower in the same location as long as they are given enough...
7. ‘Both growth and differentiation in higher plants are open’. Comment.
Solution: The existence of meristems at specific sites on the body of higher plants allows them to maintain their potential to grow indefinitely throughout their lives. These meristems give rise to...
6. Why is abscisic acid also known as stress hormone?
Solution: Abscisic acid, commonly known as stress hormone, stimulates the closing of stomata in the epidermis and increases the tolerance of plants to many forms of stressors. Abscisic acid is...
5. What do you understand by photoperiodism and vernalisation? Describe their significance.
Solution: The reaction of plants to day/night cycles is known as photoperiodism. It is thought that the hormone responsible for flowering is produced in the leaves and then migrates to the shoot...
4. List five main groups of natural plant growth regulators. Write a note on discovery, physiological functions and agricultural/horticultural applications of any one of them.
Solution: Intercellular intrinsic factors (chemical compounds) that control plant growth and development are known as plant growth regulators. The five main groups of natural plant growth regulators...
3. Describe briefly:
(a) Arithmetic growth (b) Geometric growth (c) Sigmoid growth curve (d) Absolute and relative growth rates Solution: (a) Only one daughter cell divides in arithmetic growth, while the other...
2. Why is not anyone parameter good enough to demonstrate growth throughout the life of a flowering plant?
Solution: Growth occurs when the amount of protoplasm in the body increases. Several parameters are used to measure protoplasmic growth, including height, weight, number of cells, fresh tissue...
1. Define growth, differentiation, development, dedifferentiation, development, redifferentiation, determinate growth, meristem and growth rate.
Solution: Growth – It is a permanent, irreversible rise in the size of an organ, its parts, or even a single cell. Growth is aided by metabolic activities that occur as a result of the energy...