Question

Is the experimental leaf, a monocotyledonous, or a dicotyledonous?Give a reason to support your answer.

Answer 1

Answer:

Transpiration is the evaporative loss of water through the aerial parts of the plants especially through the leaves. In all green plants transpiration occurs mostly through the stomata of the leaves. In dicot plants leaves will have more stomata on the lower surface than the upper surface. So more transpiration occurs through the lower surface of the leaves of this plant. Stomatal pores get widely opened when the leaf get exposed to bright sunlight. To avoid excessive loss of water through transpiration dicot leaves possess more stomata on the lower surface as this surface is not much exposed to sunlight.

Explanation:

this is experiment

Aim of the experiment

To prove more transpiration occurs from the lower (ventral) surface of a dicot leaf than upper (dorsal) surface. (OR) To prove unequal transpiration from the two surfaces of a dorsiventral leaf.

Requirements

A well watered potted dicot plant, strips of dry cobalt chloride paper, glass slides, clips.

Procedure for the experiment

A well watered dicot plant has to be selected for this experiment. Now two strips of filter paper are soaked in 2% solution of cobalt chloride and are perfectly dried under sunlight. Cobalt chloride paper will be blue in color when it is dry and become pink when it absorbs moisture. Due to this characteristic feature it acts as a chemical indicator in this experiment. One strip of this dry blue cobalt chloride paper is kept on either surface of a healthy dorsiventral leaf and are covered by glass slides with the help of clips. Now the whole experimental setup is kept under bright sunlight. Observe closely the changes which occur in cobalt chloride papers placed on both the surfaces.

Result

Within few minutes we observe the cobalt chloride paper kept on the lower or ventral surface of the leaf turns into deep pink color but the strip of cobalt chloride paper kept at the upper surface remains unchanged or it takes longer time to change into pale pink color. The reason for this is more stomata are present on the ventral or lower surface of a dicot leaf than the upper or dorsal surface. Due to this more water vapor from the ventral surface is released than dorsal surface and hence cobalt chloride paper kept at the lower surface changes into pink color immediately.