UV-B辐射增强对滇杨和川杨生长及生理特性的影响

Effects of Enhanced Ultraviolet-B Radiation on Growth and Physiological Characteristics of Populus yunnanensis and Populus szechuanica

在田间利用紫外灯补充紫外线B辐射(UV-B)2.5KJ/(m2·d)和5.0KJ/(m2·d),模拟云贵高原臭氧层被破坏10%、20%后UV-B增加的情况,从形态和生理方面研究不同海拔的滇杨(2 430m)和川杨(3 300m)扦插苗对UV-B增强的响应。结果表明,UV-B增强对滇杨和川杨的芽数量、叶绿素b含量及植株上部的吲哚乙酸(IAA)、玉米核苷(ZR)及脱落酸(ABA)的含量均没有明显影响,显著降低了川杨赤酶素(GA)含量(P<0.05)。2.5KJ/(m2·d)和5.0KJ/(m2·d)UV-B辐射均显著降低了滇杨的植株高度、节间长度、叶绿素a及总叶绿素含量,对过氧化物酶(POD)的活性没有影响;而川杨只在5.0KJ/(m2·d)UV-B辐射下才显著降低了株高和节间长度。可见,对于UV-B辐射增加,来自高海拔的川杨比低海拔的滇杨受的影响小,且通过提高POD活性的方式降低胁迫带来的不利影响,因而表现出了更强的耐性。

In order to understand the effects of enhanced UV-B radiation on the growth and physiological responses of Populus y＇tmnanensis 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 intemodes length were only significantly decreased by 5 KJ m^-2 day^-1UV-B radiations. This study indicated that P. szechuanica originating from high altitude was less affected 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 enhanced UV-B radiation.