Abstract

Global change will definitely introduce changes in agricultural ecosystems that will affect plant productivity. However, the effects on plants will be different for each region depending on the pre-existing climatic conditions and the adaptation potential of local cultivated species. The solar energy from the sun is essential to support the life on our plant, via the process of photosynthesis. However a small proportion of solar spectrum contains short-wavelength ultraviolet-B light (280 to 320 nm), which is deleterious to life. The depletion of stratospheric ozone layer by manmade pollution has substantially increased UV-B light impinging on the earth surface. UV-B affects living organisms by damaging cellular metabolism in several ways, such as dimmers formation in the genetic material DNA, disruption of membrane structure, inactivation of enzymes and generation of highly reactive free radicals. Elevated UV exposure also causes temporary or irreversible damage to the process of photosynthesis. Therefore, increased UV-B radiation would affect the stability of ecosystems and genetic health of living organisms. Many species of plants have evolved mechanisms for protection against deleterious effects of UV-B radiation. Accumulation of the UV-B absorbing pigments such as flavonoids is one of the ways by which plants alleviate the harmful effects of UV-B light.

Key words: Global change, agriculture, UV radiation, absorbing compounds.