Introductory Crop Physiology (1+1)

Types of Transpiration

1. Stomatal transpiration

• Most of the transpiration takes place through stomata.
• Stomata are usually confined in more numbers on the lower sides of the leaves.
• In most of the monocots, they are equally distributed on both sides of leaves, while in aquatic plants, stomata are present on the upper surface of the floating leaves.
• Stomatal transpiration accounts for 80-90 per cent of the total water loss from the plants.
2. Cuticular transpiration

• The loss of water through the impervious cuticle is called as cuticular transpiration.
• It may contribute a maximum of about 10 ten per cent of the total transpiration.
3. Lenticular transpiration

• The loss of water through the lenticels of woody stems is called as lenticular transpiration.
• It accounts for about 0.1 per cent of the total transpirational loss of water.

Distribution of stomata
The position and distribution of stomata on the two surfaces of the leaf are variable in plants and there are five types.

• Kidney shaped are found in the most of the plants including mosses, gymnosperms, dicots and many monocots.
• Dumbbell shaped or bone shaped guard cells are characteristic of grasses and hence it is also refereed as "grass type".
• Lantern types of stomata are present mostly in the CAM plants