lecture 26- plant hormones

what are the 5 major classes of plant hormones?

auxin, abscisic acid, cytokinin, ethylene, gibberellins

what is the function of auxin?

it is any chemical that promotes elongation of coleoptiles (first leaf)

what is the function of abscisic acid?

it plays a role in seed dormancy, it ensures the seed will only germinate in optimal conditions. it also allows plants to withstand drought

what is the function of cytokinin?

works with auxin to control cell division and differentiation. it works with apical dominance

what is the function of ethylene?

it produces ethylene in response to stresses like mechanical stress, senescence, leaf abscission, fruit ripening

what is the function of gibberellins?

they stimulate growth of leaves and stems via cell elongation and cell division. in seeds, it signals seeds to germinate and the endosperm to break down

what is senescence?

it is programmed death cells or organs

what is the triple response?

it is caused by ethylene and allows a growing shoot t avoid obstacles. it is also the slowing of stem elongation, thickening of stem, and horizontal growth

what hormone is responsible for the triple response?

ethylene

what is the function of expansin?

it helps with cell wall lossening and allowing cell to expand

what is etiolation and why does it occur?

a plant growing weirdly because there is no light

describe the stages and sequence of cell-signal processiing

reception- hormone binds to receptor

transduction- change in receptor relays proteins and second messengers

response- activation of cellular responses