Plant Growth Regulators in Horticulture

Question 1

Do plant growth regulators control many aspects of plant growth and development

Answer 1

no, necessary but do not control

Question 2

Plant Growth regulators

Answer 2

auxins, gibberellins, cytokinin, ethylene, abscisis acid, polyamines, jasmonates, salicylic acid, brassinosteriods

Question 3

Auxins

Answer 3

promote activity of the vascular cambium and vascular tissues, key role in fruit development, cell elongation

Question 4

Ethylene

Answer 4

Senescence, fruit abscission, maturation/ripening, and flooding responses

Question 5

Gibberellins

Answer 5

synthesized in apical portions of stems and roots, important effects on stem elongation, in some cases, hastens seed germination

Question 6

What is the difference between gibberellins and auxin cell elongation

Answer 6

GA induces cellular division and cellular elongation; auxin induces cellular elongation alone and involves the cell wall acidification,

Question 7

Cytokinis

Answer 7

promotes cell division, morphogenesis, lateral bud development, delay of senescence, shoot growth and branching

Question 8

ABA

Answer 8

abscissic acid, abscission of plant leaves, major players in mediating the adaptation of plant environmental stress, increases the tolerance of plants to various stresses, Stress Hormone

Question 9

What is ABA used for

Answer 9

bud dormancy induction, seed maturation and dormancy, abscission, apical dominance: inhibition of branching, drought stress, and stomata closure

Question 10

Polyamines

Answer 10

modulate several processes related to growth and development, cell division, rhizogenesis, senecence, flowering, fruit ripening, stress responses, DNA, RNA, and protein synthesis

Question 11

Jasmonic Acid

Answer 11

inhibit many plant processes such as growth and seed germination, promote senescence, abscission, tuber formation, fruit ripening, pigment formation

Question 12

Salicylic Acid

Answer 12

flower longevity, inhibit ethylene biosynthesis and seed germination, block wound response, reverse the effects of ABA

Question 13

Brassinosteroids

Answer 13

promotes stem elongation, inhibit root growth and development and promote ethylene and epinasty

Question 14

What PGR can be applied to increase grape berry size

Answer 14

gibberellic acid, forchlorfenuron, CPPU

Question 15

Modes of action of PGR and fruit thinning?

Answer 15

1. abortion of seeds or inhibition of seed/embryo development
2. inhibition of nutrient transport of fruit
3. inhibition of auxins synthesis and transport from fruit
4. Stimulation of Ethylene
5. Inhibition of Photosynthesis/Stimulation of Dark Respiration

Question 16

Bio-stimulants

Answer 16

diverse formulations of compounds and micro-organisms applied to plants or soils to improve crop vigor, yield, quality, and tolerance of abiotic stress

Question 17

How do bio-stimulants work?

Answer 17

improving plant metabolism, plant tolerance to abiotic stresses, facilitating nutrient assimilation, translocation and use, enhancing quality, water use efficiency