View all 40 cards in this deck

#	Question	Answer
1	What happens to seeds in the absence of favourable conditions?	They enter a period of suspended growth or rest.
2	Why is plant growth considered indeterminate?	Because plants retain the capacity for unlimited growth throughout life.
3	What is the role of lateral meristems in dicots and gymnosperms?	They increase the girth of plant organs.
4	Into how many phases is the period of growth divided?	Three phases.
5	What are the characteristics of cells in the elongation phase?	Increased vacuolation, cell enlargement, and new cell wall deposition.
6	What is secondary growth?	Increase in the girth of plant organs due to lateral meristems.
7	By how much can watermelon cells increase in size?	Up to 3,50,000 times.
8	Name the three phases of growth.	Meristematic phase, elongation phase, and maturation phase.
9	What are the characteristics of cells in the elongation phase?	Increased vacuolation, cell enlargement, and new cell wall deposition.
10	What are the two major patterns of growth rate increase?	Arithmetic growth and geometrical growth.
11	What type of curve is obtained in arithmetic growth when organ length is plotted against time?	A linear curve.
12	During which phase does geometrical growth increase rapidly?	Log phase or exponential phase.
13	In the exponential growth equation, what does (W_1) represent?	Final size (weight, height, number, etc.).
14	What is absolute growth rate?	Total growth per unit time.
15	Why are nutrients required by plants?	For synthesis of protoplasm and as a source of energy.
16	What changes occur in cells during differentiation?	Structural changes occur in cell walls and protoplasm.
17	Give examples of dedifferentiation in plants.	Formation of interfascicular cambium and cork cambium from differentiated parenchyma cells.
18	Cells pushed towards the periphery mature into what?	Epidermis.
19	How are juvenile and mature leaves different in heterophyllous plants?	Juvenile leaves differ in shape from mature leaves.
20	Which stage follows expansion (elongation) in plant cell development?	Maturation.
21	What are intercellular intrinsic factors in plants?	Chemicals such as plant growth regulators (PGRs).
22	Which PGR is derived from carotenoids?	Abscisic acid (ABA).
23	Name the plant growth-promoting PGRs.	Auxins, gibberellins, and cytokinins.
24	Who observed phototropism in coleoptiles of canary grass?	Charles Darwin and Francis Darwin.
25	Which active substance was later identified from bakanae disease studies?	Gibberellic acid.
26	Which gaseous PGR hastens ripening of bananas?	Ethylene.
27	What is a major application of auxins in plant propagation?	Initiation of rooting in stem cuttings.
28	Which hormone induces parthenocarpy in tomatoes?	Auxins.
29	Auxin controls differentiation of which tissue?	Xylem differentiation.
30	What is the nature of all gibberellins?	Acidic.
31	What is the use of GA3 in the brewing industry?	To speed up the malting process.
32	In which plants do gibberellins promote bolting?	Beet, cabbages, and rosette plants.
33	Where are natural cytokinins synthesised in plants?	In regions where rapid cell division occurs, such as root apices, developing shoot buds, and young fruits.
34	In which tissues is ethylene synthesised in large amounts?	Tissues undergoing senescence and ripening fruits.
35	How does ethylene affect seed and bud dormancy?	It breaks seed and bud dormancy.
36	Why does ethylene-induced root hair formation help plants?	It increases the absorption surface.
37	What effect does ethephon have on tomatoes and apples?	It hastens fruit ripening.
38	What type of regulator is abscisic acid (ABA)?	A general plant growth inhibitor and inhibitor of plant metabolism.
39	How does ABA help seeds survive unfavourable conditions?	By inducing dormancy, helping seeds withstand desiccation and adverse conditions.
40	What would happen if cytokinin is not added to the culture medium?	Cell division and callus proliferation would be affected.