Plant Growth and Development Flashcards
Development is the sum of the 2 processes
Growth and differentiation
Developmental processes are controlled by
Both internal and external factors
Plants have unlimited growth because of
Meristems
Lateral meristems, vascular cambium and cork cambium appear later in life in
Dicots and gymnosperms
1 maize root apical meristem can give rise to
> 17500 new cells/hour
Cells of watermelon may increase in size by upto
350000 times
3 phases of plant growth are
Meristematic, elongation, maturation
Meristematic cells have
Rich protoplasm and large conspicuous nuclei
Cells of elongation zone have
Increased vacuolation, cell enlargement, new cell wall deposition
Arithmetic growth example
Root elongating at constant rate
Arithmetic growth expression
Lt = Lo + rt [r = growth rate]
Geometric growth phases
Lag phase, log phase, stationary phase
Exponential growth equation
Wt = Wo*e^(rt) [r = relative growth rate/efficiency index]
Turgidity of cells helps in
Extension growth
Differentiation of cells into tracheids involves
Loss of cytoplasm, development of lignocellulosic, strong, elastic secondary cell wall
Interfascicular and cork cambium are formed from
Parenchyma cells by dedifferentiation
Growth and differentiation in plants is
Open type - determinate or indeterminate
Meristematic cell undergoes (diagram)
Plasmatic growth
Examples of plasticity
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]
PGRs are
Small simple molecules of diverse chemical composition
Adenine derived PGRs are
N-furfurylamino purine, kinetin
Carotenoid derived PGRs are
Abscisic acid (ABA)
Terpenes derived PGRs are
Gibberelic acid GA3
PGRs are AKA
Plant hormones or phytohormones