Tuesday, January 6, 2009

Know the Thermoregulation in Plants

Regulation of temperature is known as thermoregulation. It is almost as important as osmoregulation. Biochemical reactions of the cells are taking place under an optimal temperature. Therefore, the stability of the optimal body temperature is very essential for the normal functioning of all biological reactions. The variations in the body temperature can affect the functioning of the organisms in a very lethal way. Depending on the influence of the environmental temperature on the body temperature the animals can be of two types: ectotherms and endotherms organisms.

Ectotherms: use the external environment and behavioral mechanisms to maintain a thermal balance as much as possible. But their metabolic machinery must be generalized. The enzymes and metabolic reactions have to be functional in a wide temperature ranges. Their enzymes have the ability to work in a wide range of temperatures. For example, insects tend to be maxitherms when given the choice (fish, to digest, move down to cooler temperatures to digest food, while feeding in warm surface waters). Many ectotherms show behavioral and structural adaptations, which help them to adjust to temperature changes. For example, amphibians undergo hibernation during the hot summer. Another example, marine iguanas, feed in cold ocean waters, where they lose heat quickly. They try to gain heat by orienting their black-colored body parts directly to the radiant heat of sun. They also try to get heat by pressing their belly against the rocks that have been warmed by the sun.

Endotherms: are organisms that have a constant body temperature and use a variety of physiological mechanisms to maintain a constant internal temperature. The basic mechanism is to have a constantly active metabolic machine. Endotherms such as mammals and birds have very effective temperature control methods. They have a very high respiratory rate, which generates metabolic heat. They also conserve heat by minimizing the heat loss. The heat loss can be minimized by decreasing conductivity or by increasing insulation, or by vasoconstriction or vasodilatation, or by changing the color of insulation. For example, feathers. Air trapped in fur or feathers acts as an insulator, which prevents the loss of heat.

Panting by birds and mammals and sweating in mammals are effective methods for cooling the system. In certain organisms minimized respiration prevents the loss of excess heat from the body. In mammals there is the mechanism of thermogenesis by shivering, a type of active thermoregulation controlled by the hypothalamus of the brain through a negative feedback thermostat.

There are some leaves with a shiny leaf surface to cut down the radiant heat by reflection. Certain desert plants are provided with folded ridges on the trunks, so that sunlight falls only at shallow angles resulting in reduced absorption of radiant heat.

All living organisms are provided with different structural and physiological modifications and adaptations to maintain homeostasis.

Key words: Bio Genetics, Bio Technology

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