【摘要】 以糠椴(Tilia amurensis)幼苗为材料,运用光合测定系统和叶绿素荧光技术,从光合参数角度探究糠椴幼苗对夏季遮光环境的生态适应性。结果表明,遮光后幼苗的株高、叶面积和叶片生长量均显著增加,生长性状表现良好。在轻度遮光下幼苗的生长更加旺盛,其净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)和水分利用效率(WUE)均呈上升趋势;幼苗的初始荧光(Fo)降低,最大荧光(Fm)、最大光化学效率(Fv/Fm)和PSⅡ量子效率(Fv/Fo)均显著增加;能量分配比率参数φDo降低,其余均显著增加;反应中心活性参数DIO/RC降低趋势明显,其余参数均有所增加,遮光提高了幼苗PSⅡ反应中心活性。各参数在处理第21天或第28天变化最明显。结合隶属函数认为糠椴幼苗对轻度遮光环境有良好的生态适应性,适宜的遮光环境可以缓解高光高温对幼苗的胁迫作用,提高幼苗光合能力,并且处于旺盛生长期的幼苗对遮光响应更强烈。更多还原

【Abstract】 In this study,the Tilia amurensis seedlings were used as test materials,and the photosynthesis system and chlorophyll fluorescence technique were used to explore the ecological adaptability of alfalfa seedlings to summer shading environment from the perspective of photosynthetic parameters.The results showed that the plant height,leaf area and leaf growth of the seedlings after shading increased significantly,and the growth traits performed well. The seedlings grew more vigorously under light shading. The net photosynthetic rate(Pn),stomatal conductance(Gs),transpiration rate(Tr) and water use efficiency(WUE) all showed an upward trend. The initial fluorescence(Fo) of the seedlings decreased,the maximum fluorescence(Fm),maximum photochemical efficiency(Fv/Fm) and PSⅡ quantum efficiency(Fv/Fo) increased significantly,the energy distribution ratio parameter φDo decreased,and the rest increased significantly; The activity parameters of DIO/RC decreased significantly,and other parameters increased. Shading increased the activity of PSⅡ reaction center in seedlings.The parameters changed most significantly on the 21 st or 28 th day of treatment. Combined with the membership function,it is considered that the seedlings have good ecological adaptability to the light shading environment. The suitable shading environment can alleviate the stress of high light and high temperature on the seedlings,improve the photosynthetic capacity of the seedlings,and the seedlings in the vigorous growth period respond more strongly to the shading.更多还原