Osmoregulation in Plants and Animals

Osmoregulation in plants 

Plants are distributed in different habitats.These habitats may be aquatic, moderate, severely dry or terrestrial. Thus plants are divided into three groups on the basis of nature of habitat. These are:

Hydrophytes:

The aquatic plants are called hydrophytes. They have the adaptation to save themselves from excessive water in fresh water environment. These plants have large surface area. So transpiration takes place excessively. They have a large 'number of stomata on their upper surface, These stomata open in the atmosphere. So they promote loss of water or transpiration.

Mesophytes:

The plants, living in the moderate environment are called mesophytes. These plants have moderate water availability. When there is sufficient supply of water, the stomata are opened to promote the loss of excessive water. When there is less supply of water, the stomata are closed to prevent the loss of water eg. Brassica, rose, mango etc.

Xerophytes:

The plants living in the severely dry terrestrial environment are called xerophytes. They have following adaptation to reduce the rate of transpiration.

(i). Many xerophytes posses small thick leaves It reduces the surface are  to volume of the plants. Thus it reduces the loss of water by transpiration.

(ii). They have thick, waxy and leathery cuticle.

(iii).The stomata are on the lower surface of the leaves. These stomata are present in depressions.

 (iv). Some plants like cacti shed their leaves during the dry seasons. Therefore, the transpiration is stopped completely, They have stem as their photosynthetic organ. Their stem store water in the rainy season and use it in dry condition.

              Osmoreguiation in Animals 

The animal cells require more critical  balance of water and solutes in the body. They cannot survive without water gain or water loss. Water continuously enter or leave the cell. However, the quantity of water and the solute is kept in balance. There are two approaches in maintaining this balance:

1. Osmoconformers:

The animals which do not require to actively adjusting their internal osmotic state are called osmocoformers. These animals keep their body fluid isotonic to the external environment They even keep their body fliiid isotonic to marine and salt water environment

2. Osmoregulators:

The animals which actively adjust their internal osmotic state according to external environment are called osmoregulator. Their body fluid concentration differs greatly with outside environment. They discharge excess water in hypotonic environment and excrete salt in hypertonic environment.The animals living in diferent habitats have distinct adaptation to regulate balance.These habitats may be freshwater and terestrial environment.