gravitropism
Plants sensing down
Gravitropism is the growth response of plants to gravity.
Roots exhibit positive gravitropism, growing downward toward gravitational pull, while stems show negative gravitropism, growing upward against it.
The phenomenon explains how a seedling planted upside down will still send roots down and shoots up: The seedling's gravitropism corrected its orientation within days.
Plant growth hormone
- differential growthUnequal rates of enlargement
- root capProtective plant tissue covering
- sedimentationParticles settling in liquid
- perceptionMental interpretation of stimuli
Underground absorbing structure
At right angles groundward
- horizontalParallel to the horizon
- upwardToward a higher position
- downwardToward a lower position
- angleGeometric measure of rotation
curvature · bending · reorientation · alignment · deviation · inclination · spatial orientation
auxin
Plant growth hormone
- differential growthUnequal rates of enlargement
- root capProtective plant tissue covering
- sedimentationParticles settling in liquid
root
Underground absorbing structure
stem · radicle · vascular tissue · epidermis · cortex
vertical
At right angles groundward
- horizontalParallel to the horizon
- upwardToward a higher position
- downwardToward a lower position
angle · curvature · bending · reorientation · alignment · deviation · inclination · spatial orientation
auxin
Plant growth hormone
- ethyleneSimplest alkene, C₂H₄
- brassinosteroids
nutation
Oscillation in rotation axis
- directional growthStimulus-oriented development
gravity, gravitas, gravitate, tropism, gravitational, graviton, gravimeter, phototropism, heliotropism