growth and physiological responses to drought and elevated ultraviolet-ag贵宾会

one of the most important aspects of global change is that of stratospheric ozone depletion resulting from air pollution and the resulting increase in ultraviolet (uv) radiation reaching the surface of the earth (blumthaler and ambach 1990, erickson et al. 2000, gleason et al. 1993). photosynthetic organisms need sunligh and are thus, inevitably, exposed to uv-b radiation (jansen et al. 1998). a wealth of research efforts during the past decades were directed towards quantifying potential adverse effects of towards quantifying potential adverse effects of above-ambient uv-b fluxes on plant growth parameters (stratmann 2003). uv-b radiation along latitudinal or altitudinal gradients has resulted in plant species, popu;ations and varieties from diverse uv-b habitats developing contrasting sensitivities to uv-b radiation (bornman and teramura 1993 hofmann et al. 2001, sullivan et al. 1992, tevini and teramura 1989). earlier studies demonstrated that species and populations originating from naturally high uv-b backgrounds (e.g. high altitude and low latitude) have more pronounced adaptive mechanisms than those from low uv-b locations (e.g. low altitude and high latitude), and thus, are less sensitive to enhanced levels of uv-b (larson et al. 1990, robberecht and caldwell 1980, sullivan et al. 1992).