摘要： 研究了保护地品种津优35号、戴多星和露地品种园丰元6号黄瓜幼苗在30 μmol/(m2 · s)光照条件下,光合特性对弱光的响应.试验结果表明,弱光下黄瓜幼苗的净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)、水分利用效率(WUE)、光补偿点(LCP)、饱和光照强度(SL)、最大光合速率(Pmax)和暗呼吸速率(Rd)下降,表观量子效率升高(AQY).津优35号和戴多星胞间CO2浓度(Ci)降低、气孔限制值(Ls)升高,园丰元6号Ci上升、Ls降低.弱光导致黄瓜净光合速率下降的主要原因,保护地品种为气孔因素,露地品种为叶肉光合活性下降.RuBPCase活性的下降是黄瓜最大光合速率下降的重要原因.3个供试品种中,津优35号在弱光处理后具有相对较低的LCP和Rd,AQY上升幅度较大,表明该品种对弱光的适应能力较强.

关键词: 黄瓜, 弱光, 光合特性, RuBPCase

Abstract: Photosynthesis characteristics in seedlings of three cucumber cultivars，i.e. Jinyou No. 35，Deltasta and Yuanfengyuan No.6，under and 30 μmol / (m²·s) light density were studied. The results showed that under the weak light condition photosynthetic rate (Pn) ，conductance to H2O(Gs)，transpiration rate (Tr) ，water utility efficiency (WUE) ，light compensation point (LCP) ，saturation light intensity (SL) ，maximum photosynthetic rate (Pmax) and dark respiration rate (Rd) of cucumber seedlings decreased，but apparent quantum yield (AQY) increased. Intercellular CO2 concentration(Ci) of Jinyou No. 35 and Deltasta decreased and stomatal limitation value(Ls) increased. But Ci of Yuanfengyuan No. 6 increased and Ls decreased. The decrease in Pn of protected field cultivar was the result of stomatal limitation，that in open field cultivar was the result of photosynthetic activity decreasing. The important reason of Pmax decreasing was the decline in RuBPCase activity. Among three cucumber cultivars，Jinyou No. 35 with lower LCP and Rd，AQY increase by a bigger margin under weak light was a cultivar with weak-light adaptability.

Key words: Cucumber, Weak light, Photosynthetic characteristics, RuBPCase

中图分类号: 

• S62.22.+1