Question

State one atmospheric conditions used by plants to evolve under increasing co2 concentrations and where each carbon cycle pathway give benefit to the plant?

Answer 1

Atmospheric concentrations of CO₂ have been steadily rising, from approximately 315 ppm(parts per million) in 1959 to a current atmospheric average of approximately 385 ppm today. While great a deal of media and public attention has focused on the effects that such higher concentration of CO₂ are likely to have on Global climate , rising CO₂ concentrations are also likely to have profound direct effects on the growth, physiology and chemistry of plants, independent of any effects on climate . These effects result from the central importance of CO₂ to plant metabolism. As photosynthetic organisms, plant take up atmospheric CO₂ chemically reducing the carbon. This represents not only an acquisition of stored chemical energy , for the plant but also provides the carbon skeletons for the organic molecules that make up a plants' structure. Overall the Carbon, Hydrogen, and Oxygen assimilated into organic molecules by photosynthesis make up 96% of the total dry mass of a typical plant. Photosynthesis is therefore at the heart of the nutritional metabolism of plants, and increasing the availability of CO₂ for photo synthesis can have profound effects on plants growth and many aspect s of plant physiology.

One of the most consistent effects of elevated atmospheric CO₂ on plants is an increase in the rate of photosynthetic carbon fixation by leaves. CO₂ concentrations are also important regulating the openings of stomata, pres through which plants exchange gases , with the external environment. Open stomata allow CO₂ to diffuse into leaves for photosynthesis , but also provide a pathway for water to diffuse out of leaves. Plants therefore regulate the degree of stomatal opening as a compromise between the goals of maintaining high rate of photosynthesis and low rates of water loss. As CO₂ concentrations increase, plants can maintain high photosynthetic rates with relatively low stomatal conductance. This would be expected to decrease overall plant water use, although the magnitude of the overall effect of CO2 will depend on , how it affects other determinants of plant water use, such as plant size, morphology and leaf temperature. This in turn have consequences for the hydrological cycle of entire ecosystems,with soil moisture levels and run off both increasing under elevated CO2.

Elevated CO2 also leads to changes in the chemical composition of plant tissues.Leaf Nitrogen concentrations in plant tissues typically decrease . Protein concentrations in plant tissue are closely tied to plant Nitrogen status. Changes in plant tissue Nitrogen are therefore likely to have important effects on species at higher trophic levels.

Benefits

If CO2 is not there in the atmosphere plants will not be able to make their food and greenery will die from the earth. Oxygen is also released by the plants using the process of photosynthesis. Other living organisms can respire by using only this Oxygen released by plants. Also plants release some amount of water in the form of Transpiration. Also carbon cycle produces fuels for the human life.

From this we can conclude that life is impossible in the earth if carbon cycle is absent .