Module 2: Plant Hormones Flashcards
group of unrelated chemical substances that affect plant growth and development
phytohormones
responsible for cell elongation
auxins
stimulates proton pumps & lowers pH in cell walls; activates expansin enzymes which loosen the cellulose microfibrils of the cell walls and allows cells to expand/elongate
auxins
stimulate lateral root formation
auxins
acts as an herbicide in very high doses; stimulates ethylene production
auxins
inhibition of lateral bud formation by the apical bud
apical dominance
favors elongation of the stem as opposed to branch formation
auxins
promote plant cell division; produced in actively growing tissues (root apical meristem, embryo, fruit)
cytokinins
____ auxin to ____ cytokinin ratio will result to root formation
high auxin to low cytokinin ratio
____ auxin to ____ cytokinin ratio will result to shoot formation
low auxin to high cytokinin ratio
equal amount of the auxins and cytokinins will give rise to _____
callus tissue
promotes axillary bud growth
cytokinins
delay senescence in leaf tissues and other organs by stimulating RNA/protein synthesis and inhibiting protein breakdown
cytokinins
stimulate shoot elongation, seed germination, and fruit and flower maturation
gibberellins
induce leaf and stem growth; promote internode elongation
gibberellins
enzymes that loosen the cellulose microfibrils of the cell walls and allows cells to expand/elongate
expansins
promote fruit development; used to increase the size of fruits
gibberellins
released after seed imbibes water; triggers breaking of dormancy
gibberellins
stimulate synthesis of amylases that mobilize stored nutrients to the scutellum
gibberellins
accumulates as a response to stressful environmental conditions
abscisic acid
inhibits stem elongation and induces dormancy in lateral buds
abscisic acid
induces dormancy in seeds by blocking germination and promoting the synthesis of proteins which help the seed withstand dehydration
abscisic acid
accumulates in leaves and result to closure of stomata; signals in roots that warn the plant of water shortage
abscisic acid
associated with fruit ripening, flower wilting, and leaf fall
ethylene
regulates both growth and senescence depending on concentration, timing of application, and plant species
ethylene
promotion of fruit ripening; stimulates the conversion of starch and acids to sugars
ethylene
triggers leaf and fruit abscission, flower fading and dropping
ethylene
steroids similar to cholesterol and the sex hormones of animals
brassinosteroids
actions similar to that of auxins
brassinosteroids
play a role in plant defenses against herbivores and pathogens
jasmonates
xylem-mobile chemicals
that stimulate seed germination, suppress adventitious root formation, help establish mycorrhizal associations, and control apical dominance
strigolactones
