两种盐胁迫对苦楝幼苗光合特性的影响

Effects of Two Kinds of Salt Stress on Photosynthetic Characteristics of Melia azedaeach L. Seedlings

以一年生苦楝实生苗为试材,采用温室盆栽方式,用浓度为0%(CK)、0.2%、0.4%与0.6%的Na2SO4和Na2CO3溶液分别对幼苗进行胁迫处理21 d,比较了2种盐胁迫下幼苗光合作用和叶绿素荧光参数的变化和差异。结果表明:0.2%盐浓度对Pn、Tr、Ci、Fv/Fm、Fv/Fo、qP和NPQ没有显著影响,0.6%盐浓度则影响显著。同时,各浓度盐处理对Chl a、Chl b、Chl(a+b)、Chl a/b、Fo和Fm没有显著影响。2种盐处理对苦楝幼苗叶绿素含量没有显著影响;Na2CO3胁迫通过非气孔限制引起Pn下降,而Na2SO4引起Pn下降分别为0.2%处理时是气孔限制,0.4%和0.6%处理时是非气孔限制;幼苗光合作用和光合机构对0.2%浓度胁迫有较强耐性,对0.6%浓度胁迫耐性较弱;同时,碱性盐Na2CO3胁迫对苦楝光合作用的影响整体大于中性盐Na2SO4。

One-year-old seedlings of Melia azedaeach L.were selected as test materials and planted in pots in greenhouses.The seedlings were treated with Na2SO4 and Na2CO3 at concentrations of 0%(CK),0.2%,0.4% and 0.6% for 21 days,and the changes and differences of photosynthesis and chlorophyll fluorescence parameters of seedlings under salt stress were compared.The results showed that there was no significant difference between Pn,Tr,Ci,Fv/Fm,Fv/Fo,qP and NPQ at 0.2% salt concentration,and the difference was significant at 0.6% salt concentration.At the same time,salt treatment with different concentrations had no significant effect on Chl a,Chl b,Chl(a+b),Chl a/b,Fo and Fm.The study found that the chlorophyll content of seedlings had no significant effect under the two kinds of salt treatments;Na2CO3 stress caused a decrease in Pn by non-stomatal restriction,and the decrease of Pn caused by 0.2% Na2SO4 was stomatal limitation,and non-stomatal limitation under 0.4% and 0.6% treatment.The seedling photosynthesis and photosynthetic apparatus were more resistant under 0.2% stress.The tolerance was weak under 0.6% stress.At the same time,the effect of alkaline salt Na2CO3 stress on photosynthesis of Melia azedaeach L.was larger than that of neutral salt Na2SO4.