不同生境对赤皮青冈光合特性的影响

【目的】分析赤皮青冈Cyclobalanopsis gilva的光合作用对不同生境条件的适应特征,为赤皮青冈的良种选育和科学栽培提供理论和数据支撑。【方法】以3种不同生境条件下的赤皮青冈天然居群为研究对象,用LI-6400便携式光合仪测定天然状态下赤皮青冈的光合生理指标日变化,并得出其光响应曲线的变化规律。【结果】不同生境条件下,赤皮青冈的净光合速率与蒸腾速率变化趋势基本一致,都在10:00和14:00出现峰值,13:00出现谷值;叶片温度、光合有效辐射、气孔导度与光合速率日变化均有很强的正相关关系。光响应曲线表明:赤皮青冈利用光能的能力受不同生境条件的影响(山间平地山地阳坡山地阴坡),3种生境条件下的光补偿点(Lcp)都比较低,山地阴坡条件下Lcp最低(2.257 mol·m~(-2)·s~(-1)),山间平地和山地阳坡条件下Lcp较接近(51 mol·m~(-2)·s~(-1)左右);光饱和点(Lsp)表现为山间平地山地阳坡山地阴坡。【结论】3种生境下的赤皮青冈均具有较强的环境适应能力,赤皮青冈适应了山间平地和山地阳坡生境下光照时间长、强度大的特点,具有较强的光合能力和强光利用能力;而山地阴坡生境下的赤皮青冈提高了弱光利用能力。对不同生境条件的长期适应是赤皮青冈的光合能力产生差异的主要原因。

Effects of habitats on photosynthesis characteristics of Cyclobalanopsis gilva

Objective] To analyze the photosynthetic adaptations of Cyclobalanopsis gilva to different habitats, and provide theoretical and data supports for scientific breeding and cultivation.Method]Three natural populations of C.gilva in different habitats were studied.Diurnal changes in photosynthetic parameters of C.gilva under natural condition were measured using LI-6400 portable photosynthesis system.The light response curves were obtained.Result]Under different habitats, net photosynthetic rate(Pn) and transpiration rate(Tr) of C.gilva had similar changing patterns, both reached peak at 10:00 and 14:00, and were lowest at 13:00.Leaf temperature (θL), photosynthetically active radiation(PAR), and stomatal conductance(Gs) were all strongly positively correlated with Pn.The ability of using light for C.gilva was influenced by habitat as shown by the light response curves;C.gilva grown on flat between mountains had the best ability of using light, followed by C.gilva grown on southern slope of mountain, and then northern slope of mountain.Light compensation points (Lcp) were low in all three habitats.Lcp was the lowest (2.257 mol·m-2·s-1) for C.gilva grown on northern slope of mountain, and around 51 mol·m-2·s-1 for C.gilva grown on flat between mountains and southern slope of mountain.Light saturation point (Lsp) was the highest for C.gilva grown on flat between mountains, followed by C.gilva grown on southern slope of mountain, and then northern slope of mountain.Conclusion]C.gilva had strong adaptability to all three habitats.C.gilva grown on flat between mountains and southern slope of mountain have adapted to longer light duration and higher light intensity, and have strong photosynthetic capacity and ability of using hight light intensity.C.gilva grown on southern slope of mountain have the ability of using weak light intensity.Long adaptation to different habitats was the main cause of photosynthetic capacity differences of C.gilva.