NaCl胁迫对桑树种子萌发和Na^+/H^+逆向转运蛋白基因表达的影响  

Effect of NaCl Stress on Seed Germination and Na^+/ H^+ Antiporter Protein Gene Expression in Mulberry( Morus L. )

作　　者：刘岩 张薇 计东风 林天宝 朱燕 孟智启 吕志强 

机构地区：[1]浙江省农业科学研究院蚕桑研究所,杭州310021

出　　处：《蚕业科学》2013年第5期851-857,共7页ACTA SERICOLOGICA SINICA

基　　金：浙江省重大科技专项(No.2012C12910);浙江省蚕桑产业科技创新团队项目(No.2011R50028)

摘　　要：研究不同桑树品种种子的耐盐性及其分子机制,对桑树耐盐性品种选育以及盐碱地发展桑树产业具有重要意义。用不同浓度NaCl溶液胁迫处理几个实用杂交桑品种的种子,调查桑种子的萌发性能和Na+/H+逆向转运蛋白基因的表达水平。25 mmol/L NaCl溶液胁迫对桑种子的萌发无明显影响,仅萌发幼苗的根长、苗长稍有下降;50 mmol/L NaCl溶液胁迫后,桑种子的发芽势、含水率显著下降;150 mmol/L NaCl溶液胁迫之后桑种子的发芽率显著降低。以相对发芽势、发芽率、发芽指数计算隶属函数值综合评价供试桑品种的种子耐盐性能强弱依次为桂桑12号>桂桑62号>特优2号>特优1号。盐敏感桑品种特优1号的种子经100 mmol/L NaCl胁迫24 h后,萌发幼苗的根、茎、叶中Na+/H+逆向转运蛋白基因的表达量显著上调。研究结果显示,随着盐分胁迫浓度的升高,桑种子的萌发能力呈明显下降趋势,尤以发芽势的下降最为明显,且不同桑品种种子的耐盐能力存在差异;为应对环境中骤增的Na+,萌发幼苗体内Na+/H+逆向转运蛋白基因被诱导高水平表达。To understand seed salt tolerance of different mulberry varieties and its molecular mechanism is of great sig- nificance in breeding salt resistant mulberry varieties and developing mulberry industry in saline and alkaline land. In present study, hybrid seeds of several practical mulberry varieties were treated with NaCI solutions of different concentra- tions to investigate mulberry seed germination and expression level of Na^＋/H^＋ antiporter protein gene. The results showed that 25 mmol/L NaCI stress had no obvious influence on mulberry seed germination, except slight decreases in root length and shoot length of the germinated seedlings. Under 50 mmol/L NaCI stress, germination vigor and moisture content of the mulberry seeds decreased significantly. Under 150 mmol/L NaCI stress, germination rate of the mulberry seeds decreased significantly. According to relative germination vigor, germination rate and germination index, the membership function value was calculated to comprehensively evaluate salt tolerance of mulberry varieties. The salt toler- ance of tested mulberry varieties was in the order of Guisang 12 〉Guisang 62 〉Teyou 2 〉Teyou 1. After being treatedwith 100 mmol/L NaCI for 24 h, the expression level of Na^＋/H^＋ antiporter protein gene in root, stem and leaf of germinated seedlings of salt-sensitive mulberry variety Teyou 1 was significantly up-regulated. The above results indicated that germination ability of mulberry seeds showed a clear downward trend with the increase of salt concentration. Especially, the decrease of germinationvigor was the most obvious. Also, the salt tolerance of different mulberry varieties was different. High expression level of Na ＋/H ＋ antiporter protein gene was induced in the germinated seedlings to adapt abrupt rise of Na ＋.

关 键 词：盐胁迫 桑种子 萌发 Na+/H+逆向转运蛋白基因 

分 类 号：S888.2[农业科学—特种经济动物饲养]