3种鲜食枣品种光合作用日变化及光响应特征

Diurnal variation and light response of photosynthesis in three types of fresh jujube

对3种鲜食枣品种的光合作用日变化和光响应特征进行了观测。结果表明,3种鲜食枣的净光合速率日变化曲线均为"双峰"型,其中鲁北冬枣的日平均光合速率和蒸腾速率最高;午间光合速率降低而气孔限制值升高,表明光合速率午间降低主要是受气孔限制因素影响。光补偿点在16.0～49.1μmol·m-2.s-1之间,光饱和点在1427.8～1 642.9μmol·m-2.s-1之间,表观量子效率在0.040～0.058之间,说明这3种鲜食种均属阳性植物。在鲜食枣栽培中,应根据光合速率、水分利用率、蒸腾速率等不同光合特性来选择品种和采取相应的管理措施。

Using the GFS-3000 portable photosynthesis system, diurnal variations and light response of photosynthesis in leaves of three species of fresh jujube were investigated in this paper. The results indicated that the diurnal variation of net photosynthetic rate （Pn） exhibited dual-peak curves because of midday depression. Pn and transpiration rate （Tr） of Zizyphus Jujuba Var. inermis Lubei-dongzao cultivar were significantly higher than those of fresh jujube. The light increase in stomatal limitation （Ls） accompanied a reduction of Pn at noon indicated that the depression of photosynthetic rate was mainly due to the stomatal limitations. The light compensation point （LCP） and saturation point （LSP） were 16.0-49.1 umol.m-2.s-1 and 1 427.8- 1 642.9 umol.m-2.s-1, respectively in these cultivars, and the apparent quantum yield （AQY） were 0.040-0.058. Thus, it is suggested that the three types of fresh jujube are heliophilous plants, and that appropriate cultivars and managing methods should be chosen by different photosynthetic traits such as Pn, WUE and Tr during the production of fresh iujube.