Abstract:

In order to study the differences in character and photosynthetic among the different clones, and then develop excellent clone, the 3 years grafted seedlings of different clones selected and developed from the generation of Golden Ulmus pumila were used as materials and female parent Ulmus pumila cv. ‘Zhonghua jinye’ as control. The morphologyical characteristics and the diurnal variations of photosynthetic and fluorescence paramaters were studied. The results showed that there were significant differences on morphologyical characteristics among different clones and control. The diurnal variation of net photosynthetic rate (Pn), transpiration rate (Tr), stomata conductance (Gs) and internal cellular CO2 concentration (Ci) were different. The mean net photosynthetic rate of one day from big to small was clone C (12.35μmol/m2·s） > control（11.99μmol/m2·s）> clone B（11.98μmol/m2·s）> clone A（1080 μmol/m2·s）,which explained that the clone C developed quickly and clone A slowly on theory. There were differences on diurnal variation of Fo, Fm and Fv/Fm among different clones and control. The values of both Fm and Fv/Fm drop first and then rose again, indicating that photosynthetic activity was only temporarily inhibited while the photosynthetic organs were not damaged.  The ability of tolerant to photoinhibition of the different clones was different. Clone A was strongest inhibited and clone C was inhibited most lightly.

Key words: Ulmus pumila cv. ‘Zhonghua jinye’, clone, photosynthesis characteristics, chlorophyll fluorescence parameters, diurnal variation

摘要：

为了研究中华金叶榆不同无性系间的性状及光合特性的差异，选育优良无性系，以从中华金叶榆子一代中选择并培育的三个性状不同无性系（A、B和C）的嫁接苗为试材，以中华金叶榆母本嫁接苗为对照，对其形态特征、光合特性和叶绿素荧光参数日变化进行了研究。结果表明：各无性系和对照间的形态特征存在明显不同；净光合速率（Pn）、蒸腾速率（Tr）、气孔导度（Gs）、胞间二氧化碳（Ci）日变化均存在差异。净光合速率日均值从大到小依次为：无性系C（12.35 μmol/m2·s）>对照（11.99 μmol/m2·s）>无性系B（11.98 μmol/m2·s）>无性系A（10.80 μmol/m2·s），从理论上解释了无性系C生长速率较快，而无性系A生长速率较低原因。各无性系和对照的Fo、Fm以及Fv/Fm的日变化规律均存在明显差异。Fm和Fv/Fm都表现出下降后又上升的趋势，表明光合作用受到暂时抑制，但光合机构并没有受到损伤。不同无性的耐光抑制能力不同，无性系A受到的光抑制最强，无性系C受到光抑制最弱。

关键词: 中华金叶榆；无性系；光合特性；叶绿素荧光参数；日变化