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作 者 ：李志萍，张文辉*

期 刊 ：西北植物学报 2013年 8期 页码：1630~1637

关键词：栓皮栎；幼苗；保护酶；脯氨酸；耐盐性；

Keywords:Quercus variabilis, seedling, protective enzyme, proline, salt tolerance,

摘 要 ：为了研究栓皮栎幼苗期对盐胁迫的生理耐受特性，选择2年生栓皮栎实生幼苗为材料，在盆栽条件下，设置NaCl盐分梯度（0%、0.4%、0.6%、0.8%），系统测定分析栓皮栎幼苗在不同盐胁迫梯度和胁迫时间下的形态生长指标以及保护酶活性、脯氨酸含量、根系活力等各项生理指标。结果显示：（1）随着盐胁迫程度的加剧，栓皮栎幼苗各部分器官鲜重和干重以及株高、基径和一级侧根长均先升高后降低，而主根长度逐渐增加，叶片数逐渐减少，并在重度胁迫下达到显著水平。（2）随着盐胁迫时间的延长，栓皮栎幼苗的超氧化物歧化酶（SOD）、过氧化物酶（POD）、过氧化氢酶（CAT）活性均呈先升高后降低的趋势，但变化时间和幅度不同；丙二醛（MDA）含量则日益增加，且胁迫度越大增加越显著。（3）栓皮栎幼苗叶片的渗透调节物质脯氨酸和可溶性蛋白含量在低盐胁迫下不断升高，高盐胁迫下先升高后降低；而可溶性糖的含量则随时间延长和胁迫加剧显著增加。（4）随NaCl浓度的提高，幼苗根系活力值先增后减，叶绿素a和叶绿素b含量均呈下降趋势。研究表明，在轻、中度NaCl胁迫下，栓皮栎幼苗通过提高保护酶活性、增加渗透调节物质等策略缓解盐胁迫伤害，表现出一定的耐盐潜力；而在高浓度盐分胁迫下幼苗受到伤害，自我调节能力降低，导致保护酶活性、可溶性蛋白含量和根系活力等下降。

Abstract:To study the resistant potential of Quercus variabilis seedlings under NaCl stress,we examined the biennial cork oak seedlings grown on containers with four soil NaCl concentrations (0%,0.4%,0.6% and 0.8%).Growth index and protective enzyme activities,proline content,root activity and other physiological indexes were systematically measured and analyzed under different stress conditions and at different stress time.Results showed that:(1)With NaCl stress increasing,fresh weight and dry weight of each organ,plant height and secondary root length all increased then decreased.But the mainroot length increased and the leaf number showed a gradual reduction.（2）With the extension of stress time,three protective enzyme (SOD,POD,CAT) activities were increased before decreasing,but the variation ranges were different.Malondialdehyde (MDA) content was increased,and it grew faster at higher stress level.(3)The organic substances for osmotic adjustment such as proline and soluble protein increased at the lower stress and then decreased at the higher stress;While the content of soluble sugar was continuously increased.(4)With the NaCl concentration rising,root activity increased and then decreased;Chlorophyll a and b both showed a downward trend.It was resulted that Q.variabilis seedlings improved the characteristic of resistance to soil salt stress by increasing the activities of protective enzymes and organic substances for osmotic adjustment in low and medium NaCl stress;Under severe NaCl stress,the metabolism in vivo and self regulation ability were in disorder and deprived,causing the protective enzyme activites,soluble protein content and root activity decreasing.

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