Download Plant Hormones (Chapter 39)

Plant Hormones (Chapter 39)
Hormone
Auxins (IAA)
Where Produced
 Embryo of seed
 meristems of apical buds
 young leaves
Gibberellins




Cytokinins
 Synthesized in root
o Transported to organs
Abscisic Acid
 Leaves, Stems, Roots
 Green fruit
Ethylene
 Tissues of ripening fruits
 Nodes of stems
 Aging leaves and flowers
Meristems of apical buds
Roots
Young leaves
Embryo
Brassinosteroids  Seeds, Fruit, Shoots, Leaves
 Floral buds
Major Function(s)
 Stimulate stem elongation
 Root growth
 Cell differentiation
 Branching
 Regulated development of fruit
 Enhances apical dominance
 Functions in phototropism &
gravititropism
 Promote seed & bud germination
 Stem elongation
 Leaf growth
 Stimulate flowering and development
of fruit
 Affect root growth/differentiation
 Affect root growth/differentiation
 Stem elongation
 Leaf growth Stimulates cell
division/growth
 Stimulate germination
 Delay senescence (cell death)
 Inhibits growth
 Closes stomata during water stress
 Counter acts breaking of dormancy
 Promotes fruit ripening
 Opposes some auxin effects
 Promotes or inhibits
growth/development of roots, leaves,
flowers
 Inhibits root growth
 Retards leaf abscission
 Promotes xylem differentiation
Other Info
 Moves from cell to cell via parenchyma
tissue
 Only moves from shoot tip to base
(polar transport)
 Make fruit grow larger
 Japanese rice thing…
 cytokinin=auxin - cells grow as a
cluster of undifferentiated cells called a
callus
 more cytokinin = shoot buds
 more auxin = roots form
 Response to stress (drought, flood,
mechanical pressure, injury, infection)
 Part of triple response
 Burst associated w/ apoptosis &
absission