NO介导的Ca^(2+)信号在干旱胁迫下紫花苜蓿种子萌发及抗氧化酶中的传导作用研究  

Investigation into the mechanism of Mo-mediated Ca^(2+) signaling during seed germination and antioxidation in Medicago sativa under drought stress

作　　者：弋钦 魏小红[1] 强旭 赵颖[1] 丁春发 

机构地区：[1]甘肃农业大学生命科学技术学院,甘肃兰州730070

出　　处：《草业学报》2016年第11期57-65,共9页Acta Prataculturae Sinica

基　　金：国家自然基金项目(31560663);甘肃省自然基金项目(145RJZA196)资助

摘　　要：本试验以紫花苜蓿种子为试验材料,添加外源一氧化氮供体硝普钠(SNP)、CaCl_2及抑制剂亚甲基蓝(methylene blue,MB)和LaCl_3,对种子进行浸种处理,以研究NO介导的Ca^(2+)信号在干旱胁迫下紫花苜蓿种子萌发及抗氧化酶中的传导作用。结果表明,15%PEG胁迫下紫花苜蓿种子萌发受到明显抑制,当外源添加NO或Ca^(2+)处理后萌发指标均有上升,外施0.1mmol/L SNP或10mmol/L CaCl_2都能有效缓解PEG对紫花苜蓿种子的胁迫伤害。干旱胁迫下NO+Ca^(2+)共处理时效果最为显著,萌发率较SNP处理提高了8.96%,较CaCl_2处理提高了19.67%。共处理时比SNP、CaCl_2处理时提高了种子淀粉酶活性、淀粉含量、可溶性糖、可溶性蛋白及脯氨酸含量,降低了MDA含量和超氧阴离子产生速率,显著提高了SOD,POD,CAT活性。其中淀粉酶活性、淀粉含量、可溶性蛋白、可溶性糖、脯氨酸含量以及POD活性的变化中,均表现出:NO和Ca^(2+)共处理下各指标变化要慢于单一处理。当添加外源NO的同时添加Ca^(2+)通道抑制剂La^(3+),NO的促进效果受到抑制,而添加外源Ca^(2+)的同时添加NO抑制剂亚甲基蓝,Ca^(2+)的促进效果受到抑制,表明NO经由Ca^(2+)信号通路调控干旱胁迫下紫花苜蓿的信号传导。The Ca^2＋transduction pathways have been implicated in mediating stress response and tolerance in plants.In order to investigate the mechanism of Ca^2＋signaling mediated by nitric oxide（NO）during seed germination and antioxidation in Medicago sativa under drought stress,sodium nitroprusside（SNP,nitric oxide donor）,CaCl2,and methylene blue（NO blockers）and LaCl3（Ca^2＋channel blockers）were used in this study,and alfalfa seeds were pre-soaked with these solutions.An index of germination was markedly decreased under drought stress induced by 15% polyethylene glycol treatment,but this effect was reversed after treatments with SNP and Ca^2＋.Moreover,0.1mmol/L SNP or 10mmol/L CaCl2 alleviated drought stress damage.Compared to SNP or CaCl2 treatment alone,germination rate significantly increased by 8.96% and 19.67%respectively when the seeds were treated with both SNP and Ca^2＋.Furthermore,both SNP and CaCl2 treatments increased content of starch,soluble sugar,soluble protein and proline,and activities of amylase,superoxide dismutase,peroxidase and catalase,whereas malondialdehyde content decreased compared to that under SNP or CaCl2 treatment alone.The changes were slower for seeds receiving both NO and Ca^2＋treatments than for NO or Ca^2＋treatment alone.Interestingly,with added exogenous Ca^2＋and methylene blue,the promotional effect of Ca^2＋was inhibited.In addition,the promotional effect of NO was inhibited by La^3＋.This indicates that NO mediated protein modifications in alfalfa seeds under drought stress through the Ca^2＋signaling pathway.

关 键 词：一氧化氮 钙离子 紫花苜蓿 干旱胁迫 种子萌发 抗氧化酶 

分 类 号：S541.9[农业科学—作物学]