Advertisement

Excretion in plants , Importance & types of transpiration for the plant

From Online Sciences - January 5, 2018

The plant makes transpiration , whereas the water vapour passes from the exposed parts of plant to the surrounding air and some of it condenses and forms drops , if you add the condensed liquid to anhydrous white copper sulphate , it becomes blue , confirming that the liquid is water .

Excretion in plants

Water is absorbed by roots , Water ascends through xylem tissue of the stem to the leaves and the water lost by transpiration generates a pull to raise water upwards , There is no specialized excretory system in plants , since the excretion in plants doesnt cause any problem , this is for the following reasons :

Guttation

It is the excretion of the water drops at the leaf tips of some plants in early morning in the spring , There is a special system for guttation which consists of one or many loose cells , opening by the water stomata called the hydathode which is opened permanently day and night , The water of guttation contains the other substances which can therefore be deposited , when the water evaporates rapidly .

Transpiration

Transpiration is the loss of water in the form of water vapour , Types of transpiration are stomatal transpiration , cuticular transpiration and lenticular transpiration .

Stomatal transpiration

The loss of water in the form of the water vapour through the stomata , The amount of water lost by the stomatal transpiration is more than 90 % of the total amount of water lost in the plant , Most of transpired water is lost through the leaves , because stomata are present in plant leaves rather than in any other vegetative organ .

The mechanism of stomatal transpiration :

Cuticular transpiration

The loss of water in the form of water vapour through the epidermis covered with cuticle in the vegetative organs , The amount of water lost does not exceed 5 % of the total amount of water lost in the plant , Cuticle is a waxy layer of cutin , covering the epidermis of leaves and other plant parts , this layer repels water , but has some permeability to water vapour .

Lenticular transpiration

Importance of transpiration for the plant

Decrease of plant temperature
Ascent of water and salts from the soil

Advertisement

Continue reading at Online Sciences »