| 摘要: |
| 在自然条件下,利用CI-340便携式光合系统,对分枝期WL-232、WL-323和WL-525 3个紫花苜蓿品种(3龄1茬)的净光合速率、蒸腾速率及相关的生理因子(叶温、气孔导度、胞间CO2浓度)和生态因子(光合有效辐射、大气CO2浓度、气温、大气相对湿度)的日变化进行了测定,通过相关性及通径分析,探讨了分枝期各生理、生态因子对3个紫花苜蓿品种光合蒸腾日变化的影响。结果表明,WL-232是高光合、高水分利用和低蒸腾品种;3个紫花苜蓿品种的净光合速率(Pn)日变化均呈双峰曲线(光合“午休”现象),这是由非气孔因素所致;影响紫花苜蓿光合蒸腾的主要生态因子为大气温度,大气相对湿度为Pn的主要限制因子,大气CO2浓度为品种WL-232蒸腾速率(Tr)的主要限制因子,光合有效辐射为品种WL-323和WL-525Tr的主要限制因子;胞间CO2浓度是影响紫花苜蓿品种叶片Pn的主要生理因子,气孔导度是限制因子;叶温为影响紫花苜蓿叶片Tr的主要生理因子。 |
| 关键词: 紫花苜蓿 光合速率 蒸腾速率 分枝期 生理因子 生态因子 |
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| 基金项目:教育部重点项目（105167）；陕西省重大科技专项（STXY-01-2）；西北农林科技大学校青年基金（08080266） |
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| Analysis on relationship between diurnal changes of photosynthetic and transpiration rate of three alfalfa varieties and related factors during the branching stage |
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| Abstract: |
| Under natural conditions,the diurnal changes of photosynthetic and transpiration rate of three alfalfa varieties(WL-232,WL-323,WL-525) and related physiological and ecological factors during the branching stage of the first harvest in the third year were measured by using CI-340 portable photosynthesis system.The ecological factors included photosynthetic available radiation(PAR),air temperature(Ta),CO2 concentration in field(Ca),temperature and relative humidity(RH).The physiological factors included leaf temperature(Tl),stomatal conductance(Cs) and internal CO2 concentration.Relative analysis and path coefficient analysis were used to discuss how related factors influenced diurnal changes of photosynthetic and transpiration rate.The results showed that WL-232 was high photosynthetic,high water using and low transpiration variety.The net photosynthetic rate of the three varieties appeared to vary in a double-peak curve,and the midday depression mainly resulted from non-stomatal factors.Path coefficient analysis showed that Ta was the primary ecological determining factor for the characteristics of photosynthesis and transpiration;RH was the main limiting factor for the characteristic of photosynthesis;Ca was the main limiting factor for the characteristic of transpiration of WL-232,and PAR was the main limiting factor for the characteristic of transpiration of WL-323 and WL-525.The main physiological factor affecting the characteristic of photosynthesis of alfalfa was Ci,Cs was the main limiting factor,and Tl was the main physiological factor affecting the characteristic of transpiration of alfalfa. |
| Key words: Medicago Sativa,net photosynthetic rate,transpiration rate,branching stage,physiological factors,ecological factors |
