UV light is light below the wavelength of ________________ nm. ...

[BRWH]

UV light is light below the wavelength of ________________ nm.
 
  Fill in the blank(s) with correct word

Question 2

When plants grow too close together a shade avoidance effect occurs in their canopy. What is the shade avoidance effect and what causes it?
 
  What will be an ideal response?

[Viet Thy]

Answer to Question 1

380

Answer to Question 2

The upper layer of leaves absorb 85-90 percent of PAR light striking
them and very little far-red light. Non-absorbed light is reflected or transmitted to
lower leaves in the canopy. Therefore, leaves inside the canopy are exposed to a
high level of far-red, but low level of red light. The proportionately high level of
far-red light to red light causes the shade avoidance effect. These plants respond
with longer stem internodes, smaller leaf area, and reduced branching.