|
Return to: Biology of Horticulture |
Physiology - Transpiration
|
|
Why is transpiration an "unavoidable evil" for plants? |
|
|
They need CO2 for photosynthesis; as this diffuses in, water tends to diffuse out. |
|
|
|
|
What three environmental factors cause stomata to open? |
|
|
light, water and temperature |
|
|
|
|
How does water loss from leaf cells relate to water movement in stems? |
|
|
transpiration pulls water up (tension) |
|
|
|
|
What property of water allows for water movement to leaves? |
|
|
cohesion between water molecules under tension |
|
|
|
|
What danger exists in the cohesion mechanism of water movement and how is it different for vessels and tracheids? |
|
|
It is only possible in thin tubes. The wider the tube the more likely is the loss of cohesion - cavitation and blockage by gas bubbles. This would be more likely and more serious in vessels than in tracheids, although water can move faster in vessels than in tracheids under good conditions. |
|
|