摘要
为揭示中华金叶榆(Ulmus pumila‘Zhonghua jinye’)生长缓慢的原因,在自然条件下,以中华金叶榆为试材,以正常家榆(Ulmus pumila)为对照,对其光合特性和叶绿素荧光参数日变化进行了比较研究。结果表明:在光合参数方面,金叶榆和正常家榆叶片的净光合速率(Pn)呈典型的双峰曲线,表现出明显的光合"午休"现象,光合效率午间明显降低;二者的蒸腾速率(Tr)、气孔导度(Gs)日变化趋势和Pn相似但并不同步;胞间二氧化碳浓度(Ci)日变化趋势和Pn相反。金叶榆的Pn明显低于家榆;金叶榆的气孔导度(Gs)及蒸腾速率(Tr)均低于家榆,但胞间二氧化碳浓度(Ci)却稍高于对照,分析表明金叶榆较低的净光合速率可能是非气孔限制的结果;对于叶绿素荧光参数,初始荧光(Fo)、最大荧光(Fm)和PSⅡ原初光能转化效率(Fv/Fm)均存在明显的日变化,金叶榆所有参数均低于家榆。综合分析认为:金叶榆光合能力的缺陷可能是造成其低生长势的重要生理生态原因之一。
To reveal the cause for slow growth rate of Ulmus pumila‘Zhonghua jinye＇, the di- urnal variations of the photosynthetic and chlorophyll fluorescence characteristics of the Ulrnus pumila‘Zhonghua jinye＇ and control （Ulrnus purnila） were comparatively studied under nat- ural conditions. The results showed that the curves of diurnal variations in net photosynthetic rate （P.） of U. pumila‘Zhonghua jinye＇ and control leaves were dual-peaked with obvious midday depression of the photosynthesis efficiency. The diurnal variation trend of transpira- tion rate （Tr） and stomata conductance （Gs） were both similar with that of P, but not syn- chronism and their maximums appeared at the different times. The diurnal variation of inter- nal cellular CO2 concentration （Ci） was just opposite to that of P,. The P, of U. pumila ＇ Zhonghua jinye＇ was obviously lower than that of control. Stomatal conductance and transpi-ration rate of U. pumila ‘Zhonghua jinye＇ were generally lower than those of control, but in- tercellular CO2 of U. purnila‘Zhonghua jinye＇ was higher than that of control. Based on the analysis it was concluded that the lower P. of the U. pumila‘Zhonghua jinye＇ was resulted from nonstomata factors. As to chlorophyll fluorescence parameters of the Ulrnus purnila‘Zhonghua jinye＇, such as initial chlorophyll fluorescence （Fo）, maximum chlorophyll fluo- rescence （Fro）, optimal photochemical efficiency （Fv/Fm） of photosnystem Ⅱ all exhibited obvious diurnal variations. All the parameters of U. purnila‘Zhonghua jinye＇ were generally lower than those of the control. In conclusion, the photosynthetic capacity deficiency of U. purnila‘Zhonghua jinye＇ is one of the important physiological and ecological reasons for its lower growth potential.
出处
《河北农业大学学报》
CAS
CSCD
北大核心
2014年第6期50-55,共6页
Journal of Hebei Agricultural University
基金
河北省自然科学基金项目(C2012204085)
国家自然科学基金项目(31370664)
关键词
中华金叶榆
光合特性
叶绿素荧光参数
日变化
Ulmus pumila ‘Zhonghua jinye＇
photosynthesis characteristics
chlorophyll fluo-rescence parameters
diurnal variation
