Effects of Enhanced Ultraviolet-B Radiation on Growth and Physiological Characteristics of Populus yunnanensis and Populus szechuanica
In order to understand the effects of enhanced UV-B radiation on the growth and physiological responses of Populus yunnanensis and P. szechuanica at different altitudes of 2 430 m~3 300 m, the 10% and 20% ozone depletion in Yunnan-Guizhou Plateau were simulated by using the UV-B radiation with ultraviolet lamp supplement of 2. 5 KJm-2 day-1 and 5 KJ m-2 day-1 in the field. The results showed that enhanced UV-B radiation had little effect on bud number, chlorophyll b concentration, and IAA, ZR and ABA concentration in upper plants of two tested species whereas GA concentration was significantly reduced ( P<0. 05 ) . Plant height, internode length, and chlorophyll a and total chlorophyll concentration of P. yunnanensis were significantly reduced by both 2. 5 KJ m-2 day-1 and 5 KJ m-2 day-1 treatments, whereas little effect was observed in the Peroxidase activity ( POD) . In contrast, for P. szechuanica, plant height and internodes length were only significantly decreased by 5 KJ m-2 day-1 UV-B radiations. This study indicated that P. szechuanica originating from high altitude was less af-fected by enhanced UV-B radiation than P. yunnanensis from low altitude; moreover, stress could be reduced through increase of POD activity in P. szechuanica. Therefore, P. szechuanica showed a greater tolerance to en-hanced UV-B radiation.
Populus yunnanensisP. szechuanicaUV-B radiationGAPODchlorophyll content
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NSTL
万方数据
维普
