2种淫羊藿的光合日变化比较

Two Epimedium Species: Diurnal Variation of Photosynthesis

拟巫山淫羊藿是首个实现人工栽培的淫羊藿属植物,箭叶淫羊藿的种植生产技术仍很不成熟。为了进一步研究2种淫羊藿需光特性,为实际生产提供理论依据。本研究用CI-340型光合测定系统原位测定自然生长条件下的拟巫山淫羊藿和箭叶淫羊藿光合作用的日变化,测定光合速率(Pn)、气孔导度(C)、胞间CO_2浓度(Ci)、光合有效辐射(PAR)、相对湿度(RH)、气温(Ta)、表观叶肉导度(ALMC)、蒸腾速率(E)、叶温(Tl)、水分利用效率(WUE)等光合生理因子和环境因子,且采用相关分析、通径分析和多元逐步回归分析探讨净光合速率和生理因子的关系。结果表明:(1)拟巫山淫羊藿叶片净光合速率、表观叶肉导度和气孔导度均呈现"双峰型"变化,其净光合速率的日变化存在典型的"光合午休"现象;(2)箭叶淫羊藿的净光合速率和表观叶肉导度均高于拟巫山淫羊藿;(3)相关分析、通径分析和多元逐步回归分析表明,表观叶肉导度和胞间CO_2浓度是影响2种淫羊藿光合速率的主要因子,其中表观叶肉导度是最主要的影响因素。在实际生产中,应对2种淫羊藿采用不同的栽培策略。

Epirnedium pseudowushannense is the first cultivated species of Epimedium, but the cultivation technology of Epimediurn sagittatum is not mature yet. To further study the two kinds of Epimediurn, and provide basis for actual production, the diurnal variation of photosynthetic and eco-physiological characteristics of these two species was studied by the CI-340 Portable Photosynthesis System under natural conditions. The net photosynthetic rate （Pn）, stomatal conductance （C）, intercellular CO2 concentration （Ci）, photosynthetically active radiation （PAR）, relative humidity （RH）, air temperature （Ta）, apparent mesophyll conductance （ALMC）, transpiration rate （E）, leaf temperature （Tl）, water use efficiency （WUE） and other photosynthetic physiological factors and environmental factors were measured. The obtained data were analyzed by correlation analysis, path analysis and stepwise multiple-regression analysis to explore the relationship between the net photosynthetic rate and physiological factors. The results showed that： （1） the daily variation of Pn, E, ALMC, C of E. pseudowushanense had a ＇two peak type＇, Pn had an obviously midday depression phenomenon; （2） Pn and ALMC of E. sagittatum were significantly higher than those of E. pseudowushanense; （3） the correlation analysis, path analysis and stenwise regression analysis showed that ALMC, Ci played an important role in Pn and ranked as ALMC〉 Ci in two species. In actual production, the two kinds of Epimedium should adopt different cultivation strategies.