Page 15 - 11-Bio-14 Transport

14. Transport eLearn.Punjab

Animation 14.4: Transpiration
Source and Credit: atmos.uiuc

(i) Cuticular transpiration : The loss of water in the form of water vapours through the cuticle
of leaves is called cuticular transpiration. About 5-7% of total transpiration takes place through this
route.

The cuticle present on the upper and lower epidermis of leaves is not completely impermeable
to water and some water is lost in the form of vapours through cuticle. The thinner the cuticle
the greater is the rate of transpiration; although the composition of cuticle is also important. At
night, when the stomata are almost closed, cuticular transpiration takes place. Most of the factors
which affect rate of transpiration, in general, are also important in controlling the rate of cuticular
transpiration.

(ii) Lenticular transpiration : Lenticular transpiration is the loss of water vapours through

lenticels present in the stem of some plants. (Fig. 14.7) All plants do not possess lenticels.

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