盐胁迫对3种黄瓜砧木幼苗光合特性的影响

 研究不同浓度（0、50、100、150 mmol·L^-1）NaCl胁迫处理对3个黄瓜砧木（超级拳王南瓜、黑籽南瓜、超丰8848瓠瓜）幼苗生长、光合作用和叶绿素荧光参数的影响。结果表明，随着NaCl浓度增加，3个黄瓜砧木幼苗的地上部干鲜质量、株高、叶片数、叶片净光合速率、气孔导度、蒸腾速率逐渐降低。高盐（150 mmol·L^-1 NaCl）胁迫下，超级拳王的初始荧光（Fo）和黑籽南瓜的光化学猝灭系数（qP）显著降低，而超丰8848瓠瓜的qP显著升高。与对照相比，盐胁迫下3个砧木幼苗叶片的PSⅡ最大光化学效率(Fv/Fm)没有降低，PSⅡ电子传递量子效率（ΦPSⅡ）无显著差异。盐胁迫下超级拳王和黑籽南瓜的叶绿素a/b比值不变，超丰8848瓠瓜的叶绿素a/b比值显著下降。

Effects of NaCl Stress on Photosynthetic Characteristics of Three Cucumber Rootstock Seedlings

The effects of NaCl stress (0, 50, 100 and 150 mmol·L^-1) on the growth, photosynthesis and chlorophyll fluorescence parameters of three cucumber rootstock seedlings (Cucurbita moschata Duch. 'Chaoji Quanwang', Cucurbita ficifolia 'Heizi Nangua', Lagenaria siceraria Standl. var. clavata Makino 'Chaofeng 8848') were investigated. The results showed that the dry and fresh mass of shoot, plant height, leaf number, net photosynthetic rate, stomatal conductance and transpiration rate of three cucumber rootstock seedlings decreased gradually with increasing of NaCl concentrations. The initial fluorescence yield (Fo) of 'Chaoji Quanwang' and the photochemical quenching (qP) of 'Heizi Nangua' decreased significantly, whereas qP of 'Chaofeng 8848' increased significantly under higher salt stress (150 mmol·L^-1 NaCl). The maximal photochemical efficiency of PSⅡ (Fv/Fm) did not decrease and there was no significant difference in the quantum efficiency of PSⅡ photochemistry (ΦPSⅡ) under NaCl stress. The chlorophyll a/b ratio of 'Chaoji Quanwang' and 'Heizi Nangua' seedlings did not change significantly under NaCl salt stress, whereas that of 'Chaofeng 8848' decreased significantly.