Photoperiodism
Photoperiod triggers flowering and development
Phototropism
Response to the direction of the light
Photomorphogenesis
Spectral quality, or ratio or red/far-red is important for morphogenesis.
Low light
stress on plants, as it limits net carbon gain and plant growth.
High light
can damage photosynthetic apparatus, particularly under non-optimal conditions
Dynamic response
result of perturbations of steady state conditions; sudden changes in light (ie - sunflecks)
Steady-state response
constant response achieved after exposure of a leaf to a constant irradiance for some period of time until steady-state is reached
shade plant
can refer to a genotype which is "adapted" for shade OR to a genotype which is "acclimated".
Sun plant
can refer to plant grown in high light conditions or to a shade avoiding species
Light attenuation depends on
1. amount of leaf area
2. arrangement of leaves
extinction coefficient is __________ for vertically inclined leaves such as grass.
Lower
extinction coefficient is higher for ___________ leaves
Horizontal
extinction coefficient approaches _____ for perfectly horizontal leaves
1
Why would leaves be more vertically inclined in high light environments?
minimizes photoinhibition and increases penetration of light to lower leaves, maximizing whole-canopy photosynthesis