Campbell 39: Plant Hormones

reception, transduction, response

list the three steps in which plants respond to internal and external signals

plant hormones

chemical signals that modify or control one or more specific physiological processes within a plant

low

plant hormones are produced in very ____ concentrations, but have profound effects on growth and development

multiple; single

each plant hormone is linked to _____ effects, but multiple hormones can influence a _____ response

phototropism; elongation

_____ is the growing of a plant towards the light, due to _____ of the cells

auxin

plant hormone that stimulates cell elongation and regulates branching and organ bending
responsible for the growth response of phototropism

shoot tips; stem

auxin is produced in ____ ___ and is transported down the _____

cytokinis

plant hormone that stimulates plant cell division, promotes later bud growth, slow organ death

roots; embryos; fruits

cytokinins are produced in actively growing tissues such as ____, _____, and ______

bushier

if the terminal bud is removed, plants become ______

auxin, cytokinins, strigolactones

which three plant hormones interact in the control of apical dominance

gibberellins

plant hormone that promotes stem elongation; helps seeds break dromancy and use stored reserves

elongation; growth; germination

the plant hormone gibberellins have a variety of effects such as stem _____, fruit _____, and seed _______

abscisic acid

plant hormone that promotes stomatal closure in response to drought; promotes seed dormancy

slows

the hormone ABA _____ the growth of a plant

seed dormancy

ABA maintains this response that ensures that the seed will germinate only in optimal conditions

rain; light; cold

seed dormancy is broken when ABA is removed by heavy _____, ____, or prolonged ____

drought tolerance

ABA accumulation also causes stomata to close rapidly in response to water stress, this is known as _____ _______

ethylene

a gaseous stress response hormone that mediates fruit ripening and the triple response

stress

ethylene is produced in response to ____ such as drought, flooding, mechanical pressure, injury, and infection

triple response

the response that is induced by ethylene that allows a growing shoot to grow while avoiding obstacles

slowing of stem elongation

thickening of the stem

horizontal growth

list the three steps of the triple response

senescence

known as plant “aging", the programmed death of cells or organs

auxin; ethylene

leaf abscission is a controlled processed that is due to the change in the balance of the hormones _____ and _____

positive

ethylene triggers the ripening of fruits, then the ripening of fruits also triggers the release of more ethylene, this is known as _____ feedback

brassinosteroids

plant hormone that is chemically similar the sex hormones of animals, induces cell elongation and division, slows leaf abscission and promotes xylem differentiation

jasmonates

plant hormone that mediates plant defenses against insect herbivores; regulates a wide range of physiological processes

defense

the plant hormone jasmonates plays an important role in plant ______ and development

wounding

the hormone jasmonates is produced in response to _____

strigolactones

plant hormone that are xylem-mobile chemicals that stimulate seed germination, suppress adventitious root formation, help establish mycorrhizal associations, and help control apical dominance