P bodies are dense cytoplasmic domains many times the size of a ribosome. They are sites of translational repression that contain no ribosomes or translation factors. They are also major sites of mRNA degradation in the cytoplasm. Exon-junction complexes upf complex functions in nonsense-mediated decay and induces degradation of the mRNA by P body–associated 5′→3′ exoribonuclease XRN1 

TLS Online TPP Program

#Id: 7533

#Unit 6. System Physiology – Plant

Dense plastids serve as gravity sensors

Gravity does not form gradient.

The only way of sensing gravity is through the motion of a sedimenting body.

In plants intracellular gravity sensors are large, dense amyloplast.

Statoliths –amyloplasts that function as gravity sensors.

Statocytes-specialized gravity sensing cells in which statoliths are present.

TLS Online TPP Program

#Id: 7534

#Unit 6. System Physiology – Plant

Strigolactones as signal that interact with auxin in regulating apical dominance Strigolactone is a group of trepenoids that produced in both shoots and roots and is transported through xylem

TLS Online TPP Program

#Id: 7535

#Unit 6. System Physiology – Plant

GA levels in plants are correlated with stem length, internode elongation and seed germination. Play role in seed germination, transition to flowering, and pollen development.

TLS Online TPP Program

#Id: 7536

#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: 7537

#Unit 6. System Physiology – Plant

Gibberellins Promote Seed Germination

TLS Online TPP Program

#Id: 7538

#Unit 6. System Physiology – Plant

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