等渗Ca(NO3)2和NaCl胁迫对番茄光合作用的影响

研究了番茄的光合作用对等渗Ca(NO3)2和NaCl处理的响应。在等渗条件下120mmol.LNaCl和80mmol.LCa(NO3)2胁迫后,番茄叶片的叶绿素a、叶绿素b、总叶绿素含量、Chl.a/Chl.b比值、净光合速率(Pn)、气孔导度(Gs)、原初光能转换效率(Fv.Fm)、光合电子传递量子效率(ΦPSII)、Fv.Fo、光化学猝灭系数(qP)均呈下降趋势,以NaCl处理的下降幅度大于Ca(NO3)2处理;而Ca(NO3)2处理的胞间CO2浓度(Ci)呈下降趋势,NaCl处理的Ci呈升高趋势。因此,两种盐处理均对番茄植株光合作用造成了伤害,NaCl造成的伤害较Ca(NO3)2较为严重,Ca(NO3)2胁迫净光合速率下降可能是气孔限制所引起的,而NaCl胁迫净光合速率下降可能是由非气孔因子限制引起的。

Effects of iso-osmotic Ca(NO3)2 and NaCl treatment on photosynthesis in leaves of tomato

The effects of iso-osmotic Ca(NO₃)₂ and NaCl treatment on photosynthesis in leaves of tomato were studied. The results indicated chlorophyll content, net photosynthetic rate(Pn), stomatal conductance(Gs), intrnsic photochemical efficiency(Fv/Fm),quantum yield of PSII (ΦPSII), Fv/Fo and photochemical quenching(qP) were decreased by salt stress. However, the decreased degree of NaCl treatment was bigger than that of Ca(NO₃)₂ treatment. Intercellular CO₂ concentration(Ci) was decreased by Ca(NO₃)₂ treatment, while was increased by NaCl treatment.So both of treatments caused stress to tomato plant, and NaCl stress was heavier than Ca(NO₃)₂ stress. We could conclude that stomatal limitation was a dominating factor of Pn decrease under Ca(NO₃)₂stress and non-stomatal limitation was a dominating factor of Pn reduction under NaCl stress.