Question

b) Write a comparison between normal leaves
and leaves with white patches.​

Answer 1

Answer:

There are three things that might cause white patches on leaves -

• natural variegation
• disease (fungal, viral, bacterial)
• damage (insects, sun, breakage, etc.)

The difference between the “normal” leaf and the “patched” one usually lies on the molecular level. Either the pigment that makes the leaf green - most notably chlorophyll - is not present in the white areas (variegation,) or the molecular constituents of the pigment and surrounding cells inside the leaf have been damaged or removed by the infecting agent or by the physical damage itself.

The variegated leaf is going to do less photosynthesis than the solid-colored one, although it’s ability to move air and water through the stomata isn’t affected.

The physically damaged leaf is also going to have impaired photosynthesizing (depending on the extent of the damage,) but may well also have impairment of other leaf functions. If the damage is past a certain point, some species of plant will drop the damaged leaf.

The infected leaf will probably also be impaired in its ability to photosynthesize and carry on other life functions, but in addition, it’s harboring the infectious agent and allowing it to spread, which threatens the rest of the plant, and possibly other plants as well. The leaf may well contain some defensive compounds with which the plant is able to fight off invaders. Also, in some plant species, the plant may be able to drop the infected leaf.