Homeostasis In Plants

Maintaining balance state within the body of an organism is called homeostasis. Excretion means to get rid of toxic substances such as carbon dioxide, nitrogen wastes, shirts and excess of water. It is very important for the normal functions of the cell. Excretion is a process of homeostasis.

The average body temperature is 37°C. The enzymes of the body work best at this temperature. The maintenance of temperature of 37°C degree centigrade is called thermoregulation. The body due to changes in internal or external conditions may lose or gain heat. But the body will keep its normal temperature of 37°C by thermoregulation, a process of homeostasis.

Main toxic substance that must be removed from human body:

Human have three main excretory substance:

Carbon dioxide:

This is made by all the cells in respiration. It is transported by blood to the lungs, where it is excreted out in exhalation (breathing out).

2) Bile pigment:

These are made from Hemoglobin in liver from old red blood cells. They are carried by bile and are excreted in the form of feces.

3) Urea:

It is made in the liver from excess protein. It is carried by blood plasma to Kidneys where it is excreted in the form of urine. It contains nitrogenous excretory products, excess water, uric acid, drugs etc.

Important functions of homeostasis in an organism

There are three aspects of homeostasis. They are:

1) osmoregulation

2) excretion

3) thermoregulation

(1) Osmoregulation:

The maintenance of a balanced amount of water and dissolved salts in the body fluids (blood) are called osmoregulation. Osmosis and diffusion are essential to regulate water level in the cell.

(2)Excretion:

The removal of metabolic waste products from the body is called excretion. The harmful substance should be removed from the body through excretion. It allows the body to work normally.

(3)Thermoregulation:

The maintenance of internal body temperature to a tolerable range is called thermoregulation The enzymes of the body work best at 37°C,the optimum temperature. Mammals and birds are homoeothermic. It means they are capable of keeping their body temperature constant.

Osmoregulation in plant

Osmoregulation in plants:

The maintenance of a balanced amount of water and dissolved salts in the plants is called osmoregulation in plants. On the availability of water and salt, plants are of three main groups.

a) Hydrophytes

b) Mesophytes

c) Xerophytes

(a) Hydrophytes:

(Hydro mean water, Python-plant)

Those plants which live in water are called hydrophytes. e.g. hydrilla and water lily. Hydrophytes absorb more water than they need. Thus they have developed mechanisms to remove this extra water.

i)They have a weak root system.

ii)Large number of stomata to promote loss of water.

iii)Large surface area (broad leaves) to transpire extra water.

b) Mesophiles:

(Meso-middle, python-plant)

Mesophytes are land plants that grow in moderate condition of water. Example Brassica, rose, mango, cereal, crop etc.

i) In these plants, stomata are kept open to transfer water rapidly in a rainy season.

ii)They close stomata during limited supply of water.

c) Xerophytes:

Xerophytes are desert plants. Where there is a shortage of water. These plants grow in dry, hot and sandy places. Acacia, Aloe, cactus, opuntia are Xerophytes. They show the following adaptations to reduce the rate of transpiration.

i) long roots to absorb water

ii) steam contains water storage tissues. Stem stores water in the rainy season and uses it in dry conditions.

iii) leaves are small sticks and modified into spines to reduce transpiration.

iv) leaves are covered with thick, waxy and Leather cuticles.

v) stomata are sunken and few in number.

vi) In some Xerophytes. leaves are absent and the green stem performs the process of photosynthesis.

Excretion occurs in plants

Excretion in plants:

Excretion means the removal of waste products as a result of metabolism. Waste products are toxic and can damage the cells therefore must be removed from the body. Plants do not have special organs for excretion. The wastes that excrete by plants are CO2 produced during respiration oxygen and water during photosynthesis. It also includes some metabolic products like latex, resins and gums.

1. CO2, O2 and water are excreted through stomata. CO2 is excreted at night and O2 during day time.

2. Extra water is excreted from the margins of the leaves called hydathodes. This process is known as guttation.

3. Some waste products are stored in leaves and sepals of the flower. These parts gradually become yellow dry and eventually fall off, taking away the waste products.

4. Certain plants secret (i) gums ( Pines and keekers) (ii)latex by rubber plant and (iii) resins by glands in the plant. This material comes out by cutting or damaging some parts of the plants.