Question

a. what is meant by the electromagnetic spectrum of the solar radiation? which part is used by plants?

b.what is alternative to pest control measure to spraying of insecticide?

c. is there a difference between high response of plants and the plant adaption to environmental changes in the atmosphere?

Answer 1

a

The electromagnetic spectrum consists of the radiation of different wavelengths. Radiation is the energy that travels and spreads wherever it goes. To understand wavelength, let us imagine the ocean waves. The top of the waves is crest and the distance between two crests is called as wavelength. The electromagnetic spectrum has radiations that differ in the wavelength. The energy of the radiations can be derived from the wavelength by using the equation given in the figure. There is an inverse correlation between wavelength and energy. As shown in the figure, the wavelength of the electromagnetic radiations decreases from left to right, and hence energy increases.

The region of visible light shown in the figure is used by the plant for photosynthesis and hence it is called photosynthetically active radiation. And out of visible light only red and blue end will be used for photosynthesis. the middle part of green color is reflected by the plant and hence appeared as green.

b. Using transgenic plants that produce toxins proteins or molecules. This toxin will enter the body of pests and kills them when pests feed on plants. The best example is the transgenic Bt-cotton. This transgenic plant will secret the toxin (gene for the toxin is taken from bacterium Bacillus thuringiensis). When pest feeds on the plant leaves, toxins enter the pest gut and kill the organism.

c. Change in the environmental conditions results in the change in the plant response to adopt accordingly to conditions. These responses are governed by the plant hormonal. Plant detects the change in environmental and produces the hormone which induces the process in the plant to adopt in the changed conditions. For e.g., abscisic acid is the plant hormone involved in the transpiration process. Transpiration is the adaptive response to the increase of environmental heat. Response in the plant and plant adaption to the environment are related and not different.