Downstream of Ras is a highly conserved cascade of three protein kinases-

Ras → Raf → MEK → MAP kinase

TLS Online TPP Program

#Id: 10159

#Unit 6. System Physiology – Plant

Direct application of cytokinin to axillary buds stimulates

their growth but strigolactone suppresses axillary bud growth. Besides activating BRC1, strigolactone also inhibits cytokinin biosynthesis by negatively regulating the IPT genes.

TLS Online TPP Program

#Id: 10160

#Unit 6. System Physiology – Plant

Apical dominance is regulated by sugar availability. After decapitation, sugars, rapidly accumulate in axillary buds, stimulating bud outgrowth.

TLS Online TPP Program

#Id: 10161

#Unit 6. System Physiology – Plant

GA levels in plants are correlated with stem length, internode elongation and seed germination

TLS Online TPP Program

#Id: 10162

#Unit 6. System Physiology – Plant

The biosynthesis of gibberellins is under strict genetic, developmental, and environmental control, and numerous gibberellin-deficient mutants have been isolated. 

Mendel’s tall/dwarf alleles in peas are a famous example. Such mutants have been useful in elucidating the complex pathways of gibberellin biosynthesis.

TLS Online TPP Program

#Id: 10163

#Unit 6. System Physiology – Plant

The biosynthesis of gibberellins is under strict genetic, developmental, and environmental control, and numerous gibberellin-deficient mutants have been isolated.

TLS Online TPP Program

#Id: 10164

#Unit 6. System Physiology – Plant

Gibberellins are synthesized via the terpenoid pathway in three stages in Apical Tissues