3种鼠尾草属植物光合作用-光响应特性研究

研究丹参、宝兴鼠尾草和短唇鼠尾草光合作用-光响应特性,阐明其对环境光合特性的适应和生理响应,为丹参田间高产栽培技术、鼠尾草属野生植物资源的引种和保护提供理论依据。测定丹参、宝兴鼠尾草和短唇鼠尾草叶绿素含量,并利用LI-6400便携式光合仪研究其光合特性,同时运用直角双曲线模型、非直角双曲线模型和C₃植物光响应新模型对光响应曲线进行拟合比较研究。结果显示,3种鼠尾草属植物的叶绿素含量存在明显差异。其光响应曲线均符合C₃植物光响应新模型。丹参表观量子效率(AQY)、最大净光合速率(Pn_max)、光补偿点(LCP)均最低,分别为0.040 3,13.32 μmol/(m²·s),24.37 μmol/(m²·s);宝兴鼠尾草为最高;短唇鼠尾草居中。3种植物的净光合速率(Pn)、胞间CO₂浓度(Ci)、气孔导度(Gs)及蒸腾速率(Tr)对不同光合有效辐射(PAR)的响应均有一定程度的差异。C₃植物光响应新模型拟合的结果最好。丹参和宝兴鼠尾草不属于典型的阳性植物,短唇鼠尾草则更为耐荫。可以采取与玉米等高竿作物间作或套作,缓和蒸腾作用,以达到提高丹参净光合速率的目的。

A study on photosynthesis and photo-response characteristics of three Salvia species

To provide basic data for wild plant resources protection and cultivation of three Salvia species,the photosynthetic characteristics of adaptation and physiological response are reported in this paper.Plant chlorophyll concentrations were determined by colorimetry.Photosynthesis characteristics were evaluated using a LI-6400 portable photosynthetic system and data were fitted with different models to investigate the photosynthesis-light response curves using SPSS 18.0.Chlorophyll contents of the three Salvia species were significantly different.Photosynthesis-light response curves of all 3 plants fitted the new photosynthetic light-response model.The apparent quantum efficiency(AQY),Pnmax and LCP of S.miltiorrhiza were 0.040 3,13.32 μmol/(m2·s) and 24.37 μmol/(m2·s),respectively,and were the lowest of the three plants while those of S.paohsingensis were the highest.The light radiation net photosynthetic rate(Pn),intercellular CO2 concentration(Ci),stomatal conductance(Gs) and transpiration rate(Tr) of the three species of Salvia showed different responses to the photosynthetically available radiation flux density(PAR).The new photosynthetic light-response model gave accurate values for the physiological parameters of S.miltiorrhiza,S.paohsingensis and S.brevilabra.Neither S.miltiorrhiza nor S.paohsingensis were typical positive plants,and the shadow resistance of S.brevilabra was good.Intercropping with tall crops such as corn was good for increasing the net photosynthesis rate of S.miltiorrhiza and for retarding transpiration.