1. If a part of pith from the stem of a plant is used as an explant and cultured on nutrient medium, which of the following processes is responsible for the formation of an undifferentiated mass of cells called callus?
(a) Growth (b) Differentiation
(c) Dedifferentiation (d) Redifferentiation
2. Read the given statements to identify the phytohormone that performs these functions.
(i) Horizontal growth of seedlings, swelling of the axis and apical hook formation in dicot seedlings.
(ii) Promoting senescence and abscission of leaves and flowers.
(iii) Breaking seed and bud dormancy.
(iv) Initiating germination in peanut seeds.
(v) Sprouting of potato tubers.
(a) ABA (b) Ethylene
(c) GA (d) Cytokinins
3. Read the given statements and identify the plant hormones X, Y and Z.
(i) Hormone Y induces flowering in mango and also promotes rapid internode/petiole elongation in deep water rice plants, thus helping leaves or upper part of shoot to remain above water.
(ii) Hormone X promotes root growth and root hairs formation.
(iii) HormoneZ inhibits the seed germination, increases the tolerance of plant to various stresses, plays important role in seed development, maturation and dormancy.
(a) Y – ABA, X-Auxin, Z-GA
(b) Z – GA, X – Auxin, Y – C2H4
(c) Y – Auxin, X-C2H4, Z-GA
4. Four potted plants (I, II, III, and IV) of a short day plant, which has the critical period of 14 hours are taken and exposed to light for different time periods.The light periods given are listed in the table.
Which potted plant will show flowering after exposure to light?
(a) I (b) II (c) III (d) IV
5. Given figure shows the effect of interruption of skotoperiod (dark period) in a short day plant by light of different types.
6. Cabbage is a biennial plant which produces flowers in second year of growth. In an attempt to make it flower in a single year, four potted plants (I, II, III, and IV) of cabbage were subjected to different temperatures for several days as given in the table.
Which potted plant will show flowering?
(a) I (b) II (c) III (d) IV
7. Apples are generally wrapped in waxed paper to
(a) prevent sunlight for changing its colour
(b) prevent aerobic respiration by checking the entry of 02
(c) prevent ethylene formation due to injury
(d) make the apples look attractive.
8. The given figure shows flowering responses of three plants A, B and C to the photoperiod. Select the correct option regarding this.
|(a)||Long day plant||Day neutral plant||Short day plant|
|(b)||Short day plant||Day neutral plant||Long day plant|
|(c)||Long day plant||Short day plant||Day neutral plant|
|(d)||Short day plant||Long day plant||Day neutral plant|
9. Maryland mammoth tobacco is a short day plant. Its critical duration of darkness is 10 hours. Under which of the following conditions will it not flower?
10. In the given figure find out the absolute and relative growth rate and choose the correct option.
11. The given figure shows experiment conducted on 4 coleoptiles.
Which coleoptile bends toward the light? Choose the correct option.
(a) A and B (b) C and D
(c) A and D (d) C and B
12. If a plant needs 10 hours darkness, then identify the condition under which it will flower.
I. 14 hours day period
II. 10 hours dark period
III. 91/2 hours dark period
IV. 9 hours dark period Choose the correct option.
(a) I and III (b) II and III
(c) I and IV (d) I and II.
13. “Richmond Lang effect” refers to
(a) induction of parthenocarpy of gibberellins
(b) delaying senescence by cytokinins
(c) suppression of axillary growth by auxins
(d) stimulation of stomatal closure by abscissic acid. $14. One set of the plant was grown at 12 hours day and
12 hours night period cycles, and it flowered, while in the other set, night phase was interrupted by flash of light, and it did not produce flowers. Under which one of the following categories will you place this plant?
(a) long day (b) darkness neutral
(c) day neutral (d) short day
15. Which of the following is involved in the synthesis of plant hormone, IAA?
(a) Tryptophan (b) Tyrosine
(c) Phenylalanine (d) None of these
True or False
16. Leaves of the emergent hydrophyte, buttercup shows intrinsic plasticity.
17. Gibberellins are strongly acidic growth hormones having gibbane ring structure which causes increased internodal length of all plants.
18. Auxin promotes abscission of young leaves and fruits and delays abscission of mature or older leaves and fruits.
19. Many effects of excess auxin are actually the effects produced by ethylene.
20. Long day plants are also long night plants as they require darkness above the critical period.
21. Abscissic acid is transported to all parts of the plant through diffusion.
22. Photoperiodic response of plants is primarily controlled by light and has no genetic basis.
23. Vernalisation promotes ripeness to flower and induces flowering.
24. Supply of gibberellins induces flowering in many cases in certain short day plants under non-inductive skotoperiods.
25. Excessive presence of abscissic acid stops photosynthesis in the leaves and hence stimulates their senescence.
Match The Columns
26. Match Column-I with Column-ll and select the correct option from codes given below.
|D||Abscissic acid||(iv)||Cis sesquiterpene|
27. Match Column-I with Column-ll and select correct options from codes given below. There can be more than one match for items in Column-1.
|A||Long day plants||(i)||Short night plants|
|(xiv)||Light break reaction|
Passage Based Questions
28. (A) Complete the given passage with appropriate words or phrases.
During mid-1960s, three independent researches reported the purification and chemical characterisation of three kinds of inhibitors: (i), (ii) , and (iii). Later, all the three were proved to be chemically identical and named (iv) or (v)
(B) Read the passage and correct the errors, wherever present.
Influences of ethylene on plants include vertical growth of seedlings, shrinking of the axis and apical hood formation in monocot seedlings. Ethylene promotes senescence and abscission of plant organs, especially of leaves and roots.
Assertion & Reason
In each of the following questions, a statement of Assertion is given and a corresponding statement of Reason is given just below it. Of the statements, mark the correct answer as:
(a) if both A and R are true and R is the correct explanation of A
(b) if both A and R are true but R is not the correct explanation of A
(c) if A is true but R is false
(d) if both A and R are false.
29. Assertion : Florigen is produced only when the plants have completed juvenile stage.
Reason : It has been extracted from ‘Maryland Mammoth’ variety of tobacco by Garner and Allard.
30. Assertion: Dormancy of cereal grains allows seeds to tolerate dessication and extremes of temperature better.
Reason : ABA inhibits gibberellin mediated amylase formation during germination of cereal grains.
31. Assertion : Germination inhibitors occur in the seed coats and cotyledons of the embryos.
Reason : They inhibit germination of viable seeds in unfavourable environment.
32. Assertion: Vernalisation is a process of shortening of juvenile phase and promoting flowering by a previous cold treatment.
Reason : The stimulus for vernalisation can be transferred to nonvernalised plants.
33. Assertion : Tobacco pith culture is a bioassay for auxins.
Reason : The test can measure auxin concentrtion between 0.001-10 mg/litre.
34. Assertion : The first cytokinin was discovered from degraded autoclaved Herring sperm by Miller ef a/, 1955.
Reason : It is known as zeatin (6-hydroxy 3-methyl trans 2-butenyl amino-purine).
35. Assertion : Auxins have a masculinising effect on some plants.
Reason: Gibberellins have a feminising effect on some plants.
36. Assertion : Application of cytokinins to marketed vegetables can keep them fresh for several days. Reason : Cytokinins delay senescence of leaves and other organs by mobilisation of nutrients.
37. Assertion : Ethylene promotes apical dominance and prolongs dormancy of lateral buds.
Reason : When cytokinins are applied to lateral buds, they result in growth, despite the presence of apical bud.
38. Assertion : Auxin transport is both basipetal and acropetal.
Reason : Gibberellin transport is acropetal only.
Figure Based Questions
39. (a) Identify the growth phase represented by 1 and 2.
(i) Which of the given graphs represents 1 ?
(ii) Which of the given graphs represents 2?
40. Using the above letter/numerals fill in the given blanks.
(a) (i) growth phase cannot be sustained for long.
(b) The formula L1 = L0 + rt denotes (ii)
(c) (iii) and (iv) will result in typical sigmoid curve.
(d) (v) is also called log or exponential growth.