Plant Growth and Development

Question 1

Development is the sum of the 2 processes

Answer 1

Growth and differentiation

Question 2

Developmental processes are controlled by

Answer 2

Both internal and external factors

Question 3

Plants have unlimited growth because of

Answer 3

Meristems

Question 4

Lateral meristems, vascular cambium and cork cambium appear later in life in

Answer 4

Dicots and gymnosperms

Question 5

1 maize root apical meristem can give rise to

Answer 5

> 17500 new cells/hour

Question 6

Cells of watermelon may increase in size by upto

Answer 6

350000 times

Question 7

3 phases of plant growth are

Answer 7

Meristematic, elongation, maturation

Question 8

Meristematic cells have

Answer 8

Rich protoplasm and large conspicuous nuclei

Question 9

Cells of elongation zone have

Answer 9

Increased vacuolation, cell enlargement, new cell wall deposition

Question 10

Arithmetic growth example

Answer 10

Root elongating at constant rate

Question 11

Arithmetic growth expression

Answer 11

Lt = Lo + rt [r = growth rate]

Question 12

Geometric growth phases

Answer 12

Lag phase, log phase, stationary phase

Question 13

Exponential growth equation

Answer 13

Wt = Wo*e^(rt) [r = relative growth rate/efficiency index]

Question 14

Turgidity of cells helps in

Answer 14

Extension growth

Question 15

Differentiation of cells into tracheids involves

Answer 15

Loss of cytoplasm, development of lignocellulosic, strong, elastic secondary cell wall

Question 16

Interfascicular and cork cambium are formed from

Answer 16

Parenchyma cells by dedifferentiation

Question 17

Growth and differentiation in plants is

Answer 17

Open type - determinate or indeterminate

Question 18

Meristematic cell undergoes (diagram)

Answer 18

Plasmatic growth

Question 19

Examples of plasticity

Answer 19

Heterophylly in cotton, coriander, larkspur [leaves of juvenile plant are different in shape from mature plant]
and buttercup [difference in shapes of leaves produced in air and water]

Question 20

PGRs are

Answer 20

Small simple molecules of diverse chemical composition

Question 21

Adenine derived PGRs are

Answer 21

N-furfurylamino purine, kinetin

Question 22

Carotenoid derived PGRs are

Answer 22

Abscisic acid (ABA)

Question 23

Terpenes derived PGRs are

Answer 23

Gibberelic acid GA3

Question 24

PGRs are AKA

Answer 24

Plant hormones or phytohormones

Question 25

PGR which is both a promoter and inhibitor

Answer 25

Ethylene (mostly inhibitor)

Question 26

Discovery of all 5 types of PGRs have been

Answer 26

Accidental

Question 27

Auxin was isolated by

Answer 27

F.W. Went from tips of coleoptiles of oat seedlings

Question 28

Auxin was discovered by

Answer 28

Charles and Francis Darwin from bending of coleoptiles of canary grass in response to light (avena curvature test)

Question 29

Bakane disease of rice seedlings was caused by

Answer 29

Fungus Gibberella fujikuroi

Question 30

PGR first isolated from human urine

Answer 30

Auxins

Question 31

Gibberellins were discovered by

Answer 31

E. Kurosawa in 1926

Question 32

Cytokinins were discovered by

Answer 32

F. Skoog and Miller in tobacco stem callus from vascular tissue extract, yeast extract, coconut milk and DNA

Question 33

Who crystallized cytokinins and named it kinetin

Answer 33

Miller et. al. in 1955

Question 34

3 different names for ABA

Answer 34

Inhibitor-B, Abscission 2, Dormin [3 independent researchers]

Question 35

Ethylene as a PGR was discovered by

Answer 35

H.H. Cousins in 1910 from ripened oranges

Question 36

Naturally found auxins

Answer 36

IAA, indole butyric acid

Question 37

Synthetic auxins

Answer 37

NAA, 2,4-dichlorophenoxyacetic

Question 38

Action of auxins

Answer 38

Initiate rooting in stem cuttings, promote flowering (pineapple), prevent premature fruit and leaf drop, promote abscission of older leaves and fruits, promote apical dominance, induce parthenocarpy (tomatoes), used as herbicides (kills dicot weeds, no effect on mature monocot plants), controls xylem differentiation, helps in cell division

Question 39

Number of types of gibberellins

Answer 39

>100 [GA1, GA2, GA3, ...]

Question 40

First gibberellin to be discovered

Answer 40

GA3

Question 41

Action of gibberellins

Answer 41

Increase length of axis, elongation and shape improvement of fruits (apples), delay senescence, speed up malting process, lessens maturity period, promotes bolting (in plants with rosette habit like cabbage, beet)

Question 42

Application of gibberellins to sugarcane increases yield by

Answer 42

20 tonnes/hectare

Question 43

Cytokinins were discovered from

Answer 43

Autoclaved herring sperm DNA

Question 44

Kinetin occurs naturally in plants - true/false

Answer 44

False

Question 45

Naturally occurring cytokinin

Answer 45

Zeatin from corn kernels and coconut milk

Question 46

Natural cytokinins are synthesised where

Answer 46

Rapid cell division occurs

Question 47

Action of cytokinins

Answer 47

Promotes production of new leaves, chloroplasts, lateral shoot growth, adventitious shoot formation, helps overcome apical dominance, promotes nutrient mobilization, delays leaf senescence

Question 48

Ethylene is synthesized in large amounts by

Answer 48

Tissues undergoing senescence and ripening fruits

Question 49

Action of ethylene

Answer 49

Promotes horizontal growth of seedlings, swelling of axis, apical hook formation in dicot seedlings, promotes senescence and abscission of leaves and flowers, promotes fruit ripening, enhances respiration rate of fruits during ripening [respiratory climactic], breaks seed and bud dormancy [germination in peanut seeds, sprouting of potato tubers], promotes internode elongation, promotes root growth and hair formation, initiates flowering and synchronizing fruit set in pineapple, mango

Question 50

Most widely used PGR

Answer 50

Ethylene

Question 51

Most widely used compound as source of ethylene

Answer 51

Ethephon

Question 52

Ethephon promotes

Answer 52

Fruit ripening in tomatoes and apples, accelerates abscission in flowers and fruits (thinning of cotton, cherry, walnut), promotes FEMALE FLOWERS in CUCUMBER thereby increasing yield

Question 53

Action of abscisic acid

Answer 53

Inhibits plant metabolism, seed germination, stimulates closure of stomata, increases tolerance towards stresses, plays role in seed development, maturation, dormancy (induces dormancy)

Question 54

PGR which acts as antagonist to GAs

Answer 54

Abscisic acid

Question 55

PGR which is AKA stress hormone

Answer 55

Abscisic acid

Question 56

Vernalisation prevents

Answer 56

Precocious reproductive development late in the growing season

Question 57

Examples of biennial plants

Answer 57

Sugarbeet, cabbages, carrots

Question 58

Winter variety of wheat is harvested in

Answer 58

Mid summer

Question 59

Dormancy

Answer 59

When a seed fails to germinate even when external conditions are favourable

Question 60

Dormancy is not controlled by external environmental factors - true/false

Answer 60

True - It is only under endogenous control

Question 61

Factors promoting seed dormancy

Answer 61

Hard seed coat, presence of abscissic acid, phenolic acid, para-ascorbic acid, immature embryos

Question 62

Effect of inhibitory substances can be removed by

Answer 62

Chilling, applying GAs and nitrates