EFFECTS OF POTASSIUM SUPPLY ON PHYSIOLOGICAL PROPERTIES IN PEANUT UNDER ENHANCED ULTRAVIOLET-B RADIATION

摘要

A field experiment was conducted to investigate the influence of potassium fertilization on net photosynthetic rate (Pn), transpiration rate (Tr), stomatal conductance (Gs) and water use efficiency (WUE) of peanut at different growth stages under enhanced ultraviolet-B (UV-B) radiation. The experiment was designed with three levels of UV-B radiation, i.e. ambient UV-B radiation (CK, natural light, 1.5kJ/m(2)), enhanced UV-B by 20% (El, 1.8kJ/m(2)), enhanced UV-B by 40% (E2, 2.1kJ/m(2)) and two levels of potassium fertilization, i.e. low (K1, 75 kg K2O/hm(2)) and high (K2, 200kg K2O/hm(2)). The results showed that, compared with control, enhanced UV-B radiation decreased the net photosynthetic rate, transpiration rate, stomatal conductance, and leaf water use efficiency, and with increasing intensity of UV-B radiation, the above decreasing tendency was enhanced. Potassium supply could increase the net photosynthetic rate, transpiration rate, stomatal conductance and leaf water use efficiency, and with increasing potassium supply the above parameters were also increased. This indicated that potassium supply could mitigate the depressive effects of enhanced UV-B on photosynthesis and transpiration in peanut to some degree. This finding is helpful in further investigating the effect of potassium fertilization on yield and quality in peanut under enhanced UV-B radiation.