Biology [1 Mark Question Answer]

Present in the stoma (plural of stoma is stomata).

Present on the edges and tips of leaves of many plants.

It is a non-cellular waxy layer secreted by the epidermis and it surrounds the epidermis.

Present in the bark of woody plants.

Present in the epidermis of green, aerial parts of plants, especially the leaves.

(a) Control the size of the aperture.
(b) It also helps in photosynthesis as they contain chloroplasts also.

Plants secrete an excess of water through hydathodes when the atmosphere is very humid and the transpiration process cannot occur.

It protects the surface and reduces water loss.

They help in gaseous exchange.

(a) Loss of water vapors due to transpiration.
(b) Gaseous exchange.

The stomata close and there is a general reduction in the loss of water by the leaves due to transpiration.

It lowers the rate of transpiration thus conserving water.

The guard cells are located in the leaves. These regulate the stomatal opening for transpiration and diffusion of gases and close in order to reduce water transpiration.

Stomata present, on the leaf and open only during the day while lenticel present on the stem of woody plants and open at all times.

Guard cells regulate the opening and closing of stomata thus, control gas exchange and transpiration.

Stomata are generally found on the epidermis of the leaf.

Wind causes faster movement of air and removes the moist air and faster evaporation of water and therefore higher rate of transpiration.

(i) Some plants will die due to excessive water loss by transpiration.
(ii) Due to the high rate of transpiration plants suffer from loss of turgidity.

The humidity of the atmosphere: If the air outside is humid the rate of transpiration is reduced since the outward diffusion of internal water vapour is affected.

Bleeding

Hydathodes

Guttation

Xerophyte

Woody trees

Stomata

Lenticels

Summer

Transpiration

On a hot sunny day, the rate of transpiration exceeds the rate of water absorption by roots. As a result of this leaves collapse and plant wilts.

Hydathode: A water secreting gland found on the edges and tips of leaves of many plants.

Lenticel: A pore in the periderm of a woody stem. It acts as an organ of gaseous exchange.

Bleeding is the flow of the plant sap at the sites of injury or cuts.

Guttation is defined as the loss of water in the form of water droplets from the leaves of intact plants. It is also called exudation.

Stomatal transpiration takes place through the stomata on the leaves.

Lenticular transpiration takes place through the small openings in the corky tissue covering the stem.

Cuticular transpiration takes place through the cuticle (waxy layer) covering the leaves.

Transpiration is defined as the loss of water vapour by the plant. It may take place from any part of the plant body.