准噶尔盆地荒漠区短命植物--狭果鹤虱光合与蒸腾特性研究

PHOTOSYNTHESIS AND TRANSPIRATION OF LAPPULA SEMIGLABRA IN THE DZUNGARIA DESERT

运用LI-6400便携式光合测定系统,对准噶尔盆地荒漠区典型短命植物---狭果鹤虱(Lappulasemiglabra)净光合速率、蒸腾速率和水分利用效率特征以及光强和CO2响应曲线进行了研究,结果表明:狭果鹤虱的净光合速率日变化在生长中后期均是双峰型,而蒸腾速率日变化则是单峰型,属于非蒸腾午休型,生长中期净光合速率为生长后期的2倍;表观量子效率为0.0691,羧化效率为0.0541,与暖温带其他植物相比,狭果鹤虱对低光强和低摩尔分数的CO2有较高的利用率.

Desert spring ephemerals as pioneer plants play important roles in commumty succession, biodiversity maintenance, dune stabilization in desert ecosystems. Net photosynthetic rate, transpiration rate, water use efficiency, and photosynthetic response to photosynthesis-active radiation and COe concentration in Lappula semigabra in The Dzungaria Desert were studied with a LI-6400 portable photosynthetic system. Data showed that net photosynthetic rate in Lappula semiglabra had two daily peaks in the middle and later growing seasons, but transpiration rate had only one peak, therefore Lappula semigabra had no transpiration midday depression. Net photosynthesis rate in middle growing season was twice that in late growing season. Apparent quantum yield and carboxylation efficiency in leaves were 0. 0691 and 0. 054 1, respectively. Such values are higher than found in other plants in warm temperate zone, therefore Lappula semigabra showed higher utilization rate at lower light radiation and lower CO2 concentration.