Samenvatting Plant physiology H6: Abscisic acid
Introduction:
• Does NOT cause abscission
• Bio-assay = germination test
o ABA induces dormancy & prevents
germination
o Can be put in dose-response curve
• Vivipary = precocious germination (so before
seed dispersal)
Abscisic acid Biosynthesis:
• 2 pathways proposed:
o Direct route → C15 via farnesyl diphosphate (only in some pathogens but not
main pathway)
o Indirect route → C40 via all-trans-violaxanthin (main pathway for plants)
• Pathway is based on the terpenoid biosynthesis pathway
, • Through phytoene, -carotene is synthesized
o Desaturases remove 2 H-atoms from fatty acids each step to create a double
bound
o Symmetrical <-> asymmetrical
Introduction:
• Does NOT cause abscission
• Bio-assay = germination test
o ABA induces dormancy & prevents
germination
o Can be put in dose-response curve
• Vivipary = precocious germination (so before
seed dispersal)
Abscisic acid Biosynthesis:
• 2 pathways proposed:
o Direct route → C15 via farnesyl diphosphate (only in some pathogens but not
main pathway)
o Indirect route → C40 via all-trans-violaxanthin (main pathway for plants)
• Pathway is based on the terpenoid biosynthesis pathway
, • Through phytoene, -carotene is synthesized
o Desaturases remove 2 H-atoms from fatty acids each step to create a double
bound
o Symmetrical <-> asymmetrical
