钩栗种源间幼苗生长状况和光合特性比较研究

Comparison Study on Seedling Growth and Photosynthetic Characteristics of Castanopsis tibetana Among Different Provenances

以福建建瓯、湖北恩施、湖南浏阳、桑植、永顺等5个不同地理种源的钩栗1a生幼苗为试材,测定了幼苗高、地径和单片叶面积等生长指标;同时以不同种源的钩栗幼苗叶片为试材,动态监测了幼苗叶片的净光合速率、气孔导度、蒸腾速率、胞间CO2浓度、叶绿素含量等光合特性指标,比较分析了不同钩栗种源间生长和光合特性差异,以期为钩栗苗木培育和优良种源的选择和保护提供理论依据。结果表明:5个种源钩栗苗高、地径与单片叶面积存在显著差异,恩施种源地的各指标存在明显优势;钩栗净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)、叶绿素总量(Ct)、叶绿素a/b值(Chl a/b)在不同种源间均存在显著差异;经纬度和年无霜期是制约光合特征参数地理变异的主导因子;钩栗幼苗的净光合速率地理变异为纬度上的南-北变异;综合各方面因素,湖北恩施种源为所选种源中的最优种源。

Taking one-year seedling of Castanopsis tibetana from different geographical provenances of Jian＇ ou in Fujian, Enshi in Hubei, Liuyang in Hunan, Sengzhi in Hunan, Yongshun in Hunan as materials. Seedling height, seedling diameter and monolithic leaf area and other growth indicators were measured. meanwhile taking leaf of Castanopsis tibetana seedling as material, net photosynthetic rate （Pn）, transpiration rate （Tr）, stomatal conductance （Gs）, intercellular CO2 concentration （Ci）, chlorophyll total content （Ct）,the ratio of chlorophyll a to chlorophyll b （Chl a/b） were dynamicly monitored. Growth difference and photosynthetic characters of different provenances were comparatively analyzed ,in order to provide theoretical basis for seedlings cultivation and the selection for excellent seedling source and protection of Castanopsis tibetana. The results showed that there were significant differences between five seedlings in seedling height, seedling diameter and single leaf area, and Enshi provenance was dominated. There was significant difference in net photosynthetic rate （Pn）, transpiration rate （ Tr ）, stomatal conductance （Gs）, intercellular CO2 concentralion （Ci）, chlorophyll total content （Ct）, the ratio of chlorophyll a to chlorophyll b （Chl a/b） between five provenances. I.atitude, longitude and frostless period were the dominant factor restricted geographic variation of photosynthetic parameters. And the geographical variation of net photosynthetic rate was southnorth variation. Considering all the factors,the seedlings in Enshi Hubei was the best provenance among the selecting provenance.