酸枣的生长及生理特性对盐胁迫的响应

Response of Zizyphus Jujube Growth and Physiological Characteristics to Salt Stress

[目的]探讨酸枣幼苗对盐胁迫的适应机制及耐性机理,为盐碱地栽培品种的选择提供参考。[方法]以1年生酸枣幼苗为材料,采用盆栽控水试验,研究不同浓度0(CK),1.5,3,4.5,6,7.5g/L NaCl处理对酸枣幼苗的生长、叶绿素含量、气体交换参数、抗氧化酶活性等的影响。[结果](1)当Nacl浓度为0~3g/L时,酸枣的存活率和生长状况影响不大。当Nacl浓度>3g/L,酸枣的存活率显著下降,尤其在6~7.5g/L的高浓度胁迫下,其生长受到严重抑制,3g/LNaCl浓度是适生耐盐范围的最大阈值。(2)随着盐浓度和胁迫时间的增加,酸枣幼苗叶片中超氧化物岐化酶(SOD)活性、过氧化物酶(POD)活性、过氧化氢酶(CAT)活性呈先上升后下降的趋势,丙二醛(MDA)含量和脯氨酸(Pro)含量均为增加的趋势;(3)光和色素含量呈下降趋势,净光合速率(Pn)、气孔导度(Gs)以及蒸腾速率(Tr)呈现下降趋势,而胞间二氧化碳浓度(Ci)呈先下降后上升的趋势,其Pn的下降前期是由气孔因素引起,后期是由非气孔限制因素引起。[结论]低浓度(<3g/L)NaCl胁迫对酸枣的存活率和生长状况影响不大,但随着浓度的增加,酸枣幼苗的叶绿素含量、抗氧化酶系统等均受到抑制,植株的生长发育受到严重影响。

[Objective]To investigate the adaptation and tolerance mechanism of Zizyphus jujube seedlings to salt stress in order to provide academic reference for selection of cultivars on saline-alkali land.[Methods]Annual Zizyphus jujube seedlings was taken as research object,pot water control experiments were conducted,to study the influences of different NaCl concentration（CK,1.5,3,4.5,6,7.5 g/L）treatment on Z.jujube seedling growth,chlorophyll content,gas exchange parameters and antioxidant enzyme activity.[Results]（1） When NaCl concentration was between 0~3 g/L,there was no obvious impacts on the survival rate and growth status of Z.jujube.When the concentration of NaCl was greater than 3 g/L,the survival rate of Z.jujube dropped significantly.Especially,when NaCl concentration was 6~7.5 g/L,the growth of Z.jujube was inhibited seriously.As a result,salt tolerance of Z.jujube was 3 g/L.（2） With the increase of salt concentration and stress time,superoxide dismutase（SOD）activity,peroxidase（POD）activity,catalase（CAT）activity of Z.jujube seedling leaf showed a rising trend initially and then decreased.In contrast,the content of malondialdehyde（MDA）and proline（Pro）increased.（3） Photosynthetic pigments content showed a decline trend,similarly,net photosynthetic rate（Pn）,stomatal conductance（Gs）and transpiration rate（Tr）showed a decline trend as well.While intercellular CO2 concentration（Ci）showed a rising trend initially and then decreased.The decline of Pn was caused by stomatal factors at the beginning,and then caused by non-stoma limitation factors.[Conclusion]Low NaCl concentration（〈3 g/L）stress has little influence on the survival rate and growth status of Zizyphus jujube.But with the increase of NaCl concentration,the chlorophyll content,antioxidant enzyme system of Z.jujube seedlings will be suppressed,plant growth and development will be severely affected.