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Brassinosteroids (BAs) are a group of plant hormones.
Location, Characteristics and Occasions for Synthesis Induction
- Released in mature cells when they have less than enough sugar and oxygen to support both themselves and any dependent cells
- Released by all cells when they are experiencing conditions which would normally cause a mature root cell to produce BA or GA
- Released in response to root environmental, pest, or disease stress
Effects
- Increased rate of stem elongation
- Leaf senescence inhibition
- Involved in gravitropism
- Bending of grass leaves at the sheath/blade joints
- Inhibits leaf abscission
- Inhibits root growth
- Resistance to stress - just in the shoot. By rerouting resources from the root to the stressed shoot
- Stimulates cell elongation and division – just in the shoot
- Enhanced Ethylene production ? – induced indirectly by the causation of root cell senescence
- Promotion of growth - just shoot growth
- Xylem differentiation promotion - in order to transfer resources from cannibalized root cells
- (From Theory II of plant hormones): inhibits the rate of metabolism of cells in the shoot (who are not already at their lowest metabolism rates) in response to an decrease in the levels sugar and/or essential gases
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