plant growth and development

Question 1

what is plant growth and development?

Answer 1

understand the diversity of plant structures and life histories, need to understand role that signal response pathways play in their growth and development

Question 2

what are signal response pathways?

Answer 2

hormones and environmental stimuli alter behaviour of target cells
plants are very plastic to their environment
different responses in different tissues

Question 3

what can signals do?

Answer 3

induce changes in cell’s shape or internal structure
influence cell’s metabolism
alter gene activation and rate of protein synthesis
set in motion events that modify existing cell proteins

Question 4

where do the receptors bind to?

Answer 4

target cell’s plasma membrane on ER or cytoplasm

Question 5

what does the binding of the receptors do?

Answer 5

triggers release of internal second messenger that diffuse through cytoplasm
provides chemical signal that alters cell functioning

Question 6

what is auxins?

Answer 6

mainly indoleacetic acid (IAA)

Question 7

where is auxin synthesized?

Answer 7

apical meristem
developing leaves and embryos

Question 8

what tissues does auxin affect?

Answer 8

growing tissues
buds
roots
leaves
fruits
vascular tissue

Question 9

what are the effects of auxin?

Answer 9

governs growth responses to light and gravity
growth and elongation of stems
promote lateral roots and dormancy in lateral buds
inhibits lead abscissions
inhibits growth of lateral meristem

Question 10

what is tropism?

Answer 10

plants respond to environmental stimuli (light) and grows towards the light

Question 11

how does auxin move?

Answer 11

through polar transport from the tips of developing leaves towards the stem

Question 12

what type of plants have a high sensitivity to auxin?

Answer 12

monocots

Question 13

what is the most common type of gibberellins?

Answer 13

GA1 is most common

Question 14

where is gibberellin synthesized?

Answer 14

root and shoot tips
young leaves
developing embryos

Question 15

what effects does gibberellins have of plant tissues?

Answer 15

stems
developing seeds

Question 16

what are the effects of gibberellins?

Answer 16

promote cell divisions and growth and elongation of stems
promote seed germination
increase internodal distance

Question 17

where is abscisic acid synthesized?

Answer 17

in the leaves

Question 18

what tissues are effected by abscisic acid?

Answer 18

buds
seeds
stomata

Question 19

what are the effects of abscisic acid?

Answer 19

promotes responses to environmental stress
inhibiting growth/ promoting dormancy
stimulates stomata to close in water stressed plants

Question 20

where is ethylene synthesized?

Answer 20

shoot tips
roots
leaf nodes
flowers
fruits

Question 21

what tissues are affected by ethylene?

Answer 21

seeds
buds
seedlings
mature leaves
flowers
fruit

Question 22

what are the effects of ethylene?

Answer 22

regulates elongation and division of cells in seedling stems and roots
regulates senescence and abscission of leaves, flowers and fruits

Question 23

what is senescence?

Answer 23

again of living organisms
removal of seed pods in soybean delays senescence since ethylene is not produced

Question 24

what is dehiscence?

Answer 24

shed ripened grains

Question 25

what is indehiscence?

Answer 25

hold on to ripened grains

Question 26

what does ethylene promote?

Answer 26

horizontal growth

Question 27

what is the most abundant cytokinin?

Answer 27

zeatin

Question 28

where is cytokinin synthesized?

Answer 28

mainly root tips

Question 29

what tissues are effected by cytokinin?

Answer 29

shoot apical meristem leaves buds

Question 30

what are the effects of cytokinin?

Answer 30

promote cell divisions and growth and elongation of stems promote seed germination inhibits leaf aging

Question 31

what are brassinosteroids?

Answer 31

group of steroid hormones

Question 32

where are brassinosteroids synthesized?

Answer 32

young seeds, shoots and leaves

Question 33

what tissues are mainly effected by brassinosteroids?

Answer 33

mainly shoot tips developing embryos

Question 34

what are the effects pf brassinosteroids?

Answer 34

stimulate cell division and elongation differentiation of vascular tissue

Question 35

what are jasmonates?

Answer 35

JA derived from fatty acids

Question 36

where are jasmonates synthesized?

Answer 36

roots seeds probably other tissues

Question 37

what tissues are effected by jamonates?

Answer 37

various tissues including damaged ones

Question 38

what are the effects of jamonates?

Answer 38

in defense response promote transcription of genes encoding protease inhibitors possible role in plant responses to nutrient deficiencies

Question 39

what are plants chemical defense system?

Answer 39

prevent or mediate damage to plant tissues from infectious bacteria, fungi, worms or plant eating insects

Question 40

what is a hypersensitive response?

Answer 40

isolates infection site by surrounding with dead cells salicylic acid induces synthesis of pathogenesis related proteins

Question 41

what is secondary metabolites?

Answer 41

commonly mediate a plant's antagonistic interactions not essential for growth and life but help with a plant's defense against with pathogens and herbivores

Question 42

what is gene for gene recognition?

Answer 42

enables plants to recognize pathogen chemically an mount defenses against it

Question 43

what is systemic acquired resistance?

Answer 43

provides long term protection against some pathogens

Question 44

what is phototropism?

Answer 44

growth response to directional light source blue light receptors trigger auxin transport auxin triggers differential cell elongation

Question 45

what is gravitropism?

Answer 45

growth response to earth's gravitational pull - statoliths move in response to gravity

Question 46

what it thigmotropism?

Answer 46

growth in response to contact with a solid object

Question 47

what is thigmomorphogenesis?

Answer 47

mechanical stress causes the stem to add girth - caused by frequent strong winds, rainstorms, grazing animals and even farm machinery

Question 48

what is nastic movement?

Answer 48

reversible response to nondirectional stimuli - movement in leaves, leadlets and flowers

Question 49

what are circadian rhythms in plants?

Answer 49

24 hours cycles even when environmental conditions remains consistent - regulated by a biological clock and helps ensures that of single species do the same

Question 50

what is a biological clock?

Answer 50

internal time-measuring mechanisms with a biological basis - adapt organisms to recurring environmental changes

Question 51

what are environmental cues can reset clocks?

Answer 51

enables seasonal adjustments in growth development and reproduction

Question 52

what is photoperiodism?

Answer 52

responses to change in relative length of daylight and darkness allows biological clock to be reset for seasonal adjustments to day length controlled by phytochrome

Question 53

what is phytochrome?

Answer 53

blue green pigment converts to active form during daylight when red wavelengths dominate reverts to inactive form a sunset at night or in shade when far red wavelengths predominate

Question 54

what does phytochrome control?

Answer 54

types of enzymes produced in particular cell used to sense long nights of autumn in preparation for dormancy

Question 55

what is a flowering response?

Answer 55

long day plants short day plants intermediate day plants day neural plants

Question 56

what is a long day plant?

Answer 56

flowers in spring or summer when day length is long relative to night

Question 57

what is a short day plant?

Answer 57

flower in late summer or autumn when day length is relatively short

Question 58

what is an intermediate day plant?

Answer 58

in between long and short day plants

Question 59

what is a day neutral plant?

Answer 59

flowering not affected by photoperiod