Question

In an experiment, four freshly plucked leaves (A - D) of a plant, such as those of China-Rose, were treated as follows :

(A) coated with vaseline on its upper surface.

(B) coated on the lower surface.

(C) coated on both surfaces.

(D) left uncoated.

All the four leaves A, B, C and D were left in a room for about 24 hours.

(i) Which leaf would become most limp ? Why ?

(ii) Which leaf would show least limping ? Why ?

Answer 1

Since this experiment is not an effort to destarch the leaf hence whether the room is dark or well lit is not important.

We know that the dorsal side (the side that faces the sun ) of the leaf has the least number of stomata. the ventral side of the leaf that faces the ground has the most number of stomata.

Vaseline cover will prevent water loss through transpiration hence the cells in the leaf will continue to remain turgid and the leaf will continue to be fresh

.Option (c) fits the condition. It will exhibit the least amount of limp.

The leaf which is uncoated will lose maximum water through transpiration, the cells will become flaccid and the leaf will limp.

Option (d) fits the condition.