Abstract: Studies on the effects of enhanced solar UV radiation on the growth and physiology of soybean and wheat show that under natural conditions,the increase of UV radiation can inhibit the net photosyntetic rate and the growth of leaves,stems and roots of both tested crops.The decrease of biomass and yield is caused by the decline of transpiration and stomatal conductance of leaves.Estination of the crop response on the enhanced UV radiation shows that the mean error between fitting value and observed one is 0.30～8.56%.

Key words: Ultraviolet radiation, Soybean, Wheat, Growth, Biological response, stable isotope, photosynthesis, respiration, environmental factors