Plant growth n dev Flashcards
growth means
irrev, permanent increase in size of organ/cell
Unique feature of plant growth
unlimited growth
meristems have the capacity to
divide and self perpetuate
form of growth where new cells are added to plant by meristem activity is called
open form of growth
primary growth
growth of shoot and root apical meristems
-contribute to elongation of plant abt axis
secondary growth
lateral meristems- vascular and cork cambium help in increase of girth size
(mainly in dicots and gymno)
growth of cell measured by
increase in protoplasm size
increase in cells of maize
17,500/hr
increase in size of watermelon—
(cucurbita melo)- 3,50,000
ways of measuring growth- 5
increase in:
-number of cells
-size
-surface area (leaf)
-volume
-length (stem, root, pollen tube)
Growth is measured by
Auxanometer
abundant plasmodesmatas are seen in
meristamatic region
new cell wall deposition is seen in
elongation region
increased vacuolation is seen in —- region
elongation
intercellular spaces are absent in — region
meristamatic
primary cell wall (thin and cellulosic) is found in
meristamatic
maximal size in terms of — and — is attained in maturation phase
wall thickening and protoplasm modifications
cells rich in protoplasm with large conspicuous nuclei is found in
meristamatic
growth rate ===
growth/unit time
arithmetic growth
1 daughter continues to divide, the other differentiates
ex: Root, shoot elongation
eq of arithmetic growth
L(t) = L(0) + rt
curve of arithmetic growth
linear- straight line
geo growth
both daughter cells continue to divide
ex: early embryonic dev/in uni
eq of geo growth
W(1) = W(0)e^rt
geo growth graph
sigmoid curve- characteristic of living orgs growing in a natural environment
describe growth in geo growth wrt time
initial- lag phase- slow growth
mid- log/exponential phase
(GRAND PHASE)
end- Steady/stationary phase
Efficiency index
Relative growth rate (r)- measures ability of plant to produce new material
diff b/w absolute and relative growh rates
absolute- total growth/time
relative- absolute/intial*100
Cell enlargement requires
water (turgidity helps in growth, also provides medium for enzymatic activities for growth)
oxygen helps in — for plant growth
releasing metabolic energy
— are req for synthesis of protoplasm
nutrients (also act as a source of energy)
environmental factors for plan growth
optimum temp, light, gravity, etc
—-,—- and — cells differentiate
root and apical meristems, cambium (primary meristems)
primary meristems differentiate to form
primary permanent tissues (prim xylem, phloem and cortex)
interfascicular cambium and cork cambium are —- formed by —-
secondary meristems, dedifferentiation of prim permanent tissues
redifferentiation of — produces —
secon meristems, secon permanent tissues (secon xylem, phloem, cortex/phelloderm, cork/phellem)
differentiation in plants is — because
open, cells from same meristem may develop diff structures upon maturity
formation of tracheary element is a form of
differentiation
final structure of cell at maturity is also determined by
location of cell within plant body
(ex: cells away from root apical meristem become root cap and those at periphery become epidermis)
Dev includes changes from — to —-
germination to senescence
plasticity means
ability of plants to produce diff structures wrt environment/life stage
Heterophylly (dev)
larkspur, coriander, cotton
Heterophylly (envi)
Rannanculus (buttercup) and Limnophylla
dev is the sum of
growth and differentiation
plant hormones (PGRs)==
phytohormones
growth promoters help in cell division, elongation, fruit, flower and seed formation, and —–, —–
tropic growth, pattern formation
auxin is derived from
Indole
Indole-3-acetic acid
Cytokinin is derived from
Adenine derivative
(N^6-furfurylamino purine==kinetin)
Turpene derivates are
Gibberelins (Gibberellic acid)
plant growth inhibitors also help in
Plants responses to wounds and stress
____ observed auxin in
Charles and francis darwin
Canary grass
____ isolated auxin in —-
F W Went
oats- Avena Sativa (1st plant to isolate auxin from)
1st auxin was to be isolated from
human urine
Bio assay of auxin
Avena Curvature test/Quantitative test
Auxein means
to grow- greek word
biosynthesis of auxin
by Tryptophane and Zinc ions
Natural auxins are
Indole acetic acid
Indole butyric acid
Artificial auxins are
naphthalene Acetic acid
2,4 dichlorophenoxy acetic acid
2,4,5 trichlorophenoxy acetic acid
Characteristic function of auxin
Apical dominance
Pruning to prevent apical dominance is done in
Tea plantations and hedges
Auxin promotes flowering in
Pineapple and litchi
Auxin is synthesised in
Root and shoot apex
auxin induces parthenocarpy in
tomato- IAA
—– auxin is used to kill dicot weeds
2, 4 D
—- helps in xylem differentiation
auxin
Bolting is promoted by
gibberelins (internode elongation just before flowering)
characteristic function of gibberelins
internode/stem elongation
gibberelin was discovered by ——- in
E Kurosawa
Bakane- foolish seedling disease on rice by Gibberella fugikuroi
Term gibberellins was given by
Yabuta and sumukhi
Gibberelins promote elongation of
genetically dwarf plants (Maize, pisum)
Cabbage, beet
Grape and apple stalks
sugarcane (increases yield by 20 tonnes/acre)
—– help increase shelf life
gibberellins
they delay senescence
seed germination is done by —- hormone
gibberellins
induces synthesis of lipase, amylase and protease
gibberellins are used in brewing industry to
increase malt formation
effect of gibberellins in conifers
promotes maturity— early seed production
bio assay of gibberellins
synthesis of alpha amylase enzyme for seed germination
cytokinin was obtained from
autoclaved herring sperm’s dna
isolation of zeatin from corn kernels and coconut milk
cytokinin was observed by—-
discovered by
skoog
miller
cytokinin + gibberellin===
pomalin (apple size enlarger)
cf of cytokinin
cell division
—- helps in morphogenesis
cytokinin
for root differentiation
high auxin, less cytokinin
opp for shoot
Richmond lang effect
inhibits senescence (Bio assay) as they help in nutrient mobilization
cytokinin helps produce new —-
leaves and chloroplasts
lateral growth and adventitious shoot formation is promoted by —–
cytokinin
