摘要： 研究不同浓度(50,100,150,200 mmol/L)NaCl胁迫对莴苣幼苗生长和叶片光合特性的影响,结果表明,在盐胁迫下,植株株高和根长生长都受到明显的抑制;叶片中叶绿素(Chl)含量随着处理浓度的增加和时间的延长呈现下降的趋势,但是50 mmol/L NaCl处理中Chl含量却有所增加,盐胁迫对叶绿素a(Chla)的影响大于叶绿素b(Chlb)。在盐胁迫下净光合速率(Pn)呈下降趋势,气孔导度(Gs)和蒸腾速率(Tr)的变化趋势与Pn相一致;50 mmol/L NaCl处理中,随着处理时间的延长,Gs和胞间CO₂浓度(Ci)呈相同的变化趋势,此时Pn的下降主要是气孔限制,而在100-200mmol/L NaCl处理中,随着处理时间的延长,Gs和Ci呈相反的变化趋势,此时Pn的下降主要是非气孔限制。

关键词: 盐胁迫, 光合性能, NaCl, 莴苣

Abstract: Effects of NaCl stress in different concentration on growth and photosynthetic characteristics in leaves of lettuce seedlings were studied.The results showed that the plant height and root length were inhibited obviously.The con- tent of chlorophyll decreased with the NaCl concentration and treated time.However,it increased under 50 mmol/L NaCl. The content of chlorophyll a dropped more rapidly than that of chlorophyll b. The net photosynthetic rate (Pn),stomatal conductance(Gs)and transpiration rate(Tr)changed similarly with increasing salt stress,and all decreased.Stomatal con- ductance and intercellular concentrations of CO₂ (Ci) changed similarly under 50 mmol/L NaCl stress.The changes of stomatal conductance were contrary to intercellular concentrations of CO₂ under 100 - 200 mmol/L NaCl. It was stomatal limitation that leading the photosynthesis declined in the treatments with lower concentrations.On the contrary,non-stom- atal limitation was the dominative causation in the treatments with higher concentrations.

Key words: Salt stress, Photosynthesis, NaCl, Lettuce

中图分类号: 

• S636.2