Transpiration
The loss of water in the form of water vapour from the aerial part of the
plant is called transpiration.
TYPES OF TRANSPIRATION
All the above ground plant parts participate in the process of transpiration.
The transpiration takes place through the leaves; young stems, flowers and fruits also transpire
a lot.
1. Stomatal Transpiration
This is the main form of transpiration and accounts for 50-95% of the water transpired from the
leaves through stomata during the day time..
These water vapours are released to the outside in two phases by the process of diffusion.
2. Cuticular Transpiration
Cuticular transpiration occurs through the cuticle (made up epidermal cells of the leaves and
other parts of the plant. This type of transpiration 5-10% of the total water loss from the leaves.
If the cuticle is very thin, the contribution of cuticular transpiration can be high.
3. Lenticular Transpiration
Lenticular transpiration is loss of water vapours through lenticels (tiny openings on the woody
stems). It accounts for only 0.1% of the total water losses transpiration. Lenticular transpiration
is important in deciduous trees during winter in the region.
SIGNIFICANCE OF TRANSPIRATION
Transpiration has beneficial as well as harmful effects in plant life. These effects are discussed
below:
Beneficial Effects of Transpiration
Ascent of Sap
The actively transpiring leaves generate a transpiration pull in the xylem column which is
responsible for ascent of sap. In this way, the water and minerals move from the tip of the root
to the leaves elements.
The loss of water in the form of water vapour from the aerial part of the
plant is called transpiration.
TYPES OF TRANSPIRATION
All the above ground plant parts participate in the process of transpiration.
The transpiration takes place through the leaves; young stems, flowers and fruits also transpire
a lot.
1. Stomatal Transpiration
This is the main form of transpiration and accounts for 50-95% of the water transpired from the
leaves through stomata during the day time..
These water vapours are released to the outside in two phases by the process of diffusion.
2. Cuticular Transpiration
Cuticular transpiration occurs through the cuticle (made up epidermal cells of the leaves and
other parts of the plant. This type of transpiration 5-10% of the total water loss from the leaves.
If the cuticle is very thin, the contribution of cuticular transpiration can be high.
3. Lenticular Transpiration
Lenticular transpiration is loss of water vapours through lenticels (tiny openings on the woody
stems). It accounts for only 0.1% of the total water losses transpiration. Lenticular transpiration
is important in deciduous trees during winter in the region.
SIGNIFICANCE OF TRANSPIRATION
Transpiration has beneficial as well as harmful effects in plant life. These effects are discussed
below:
Beneficial Effects of Transpiration
Ascent of Sap
The actively transpiring leaves generate a transpiration pull in the xylem column which is
responsible for ascent of sap. In this way, the water and minerals move from the tip of the root
to the leaves elements.
