NaCl对泌盐红树和非泌盐红树Cd吸收和积累的影响  

Effects of NaCl on cadmium uptake,accumulate in secretor and non-secretor mangrove species

作　　者：向敏[1] 孙会敏[2] 王少杰[2] 郎涛[2] 马旭君[2] 李妮亚[1] 陈少良[2] 

机构地区：[1]海南师范大学生命科学学院 [2]北京林业大学生物科学与技术学院

出　　处：《北京林业大学学报》2016年第8期10-17,共8页Journal of Beijing Forestry University

基　　金：国家自然科学基金项目(31270654;31160150;31570587);教育部科学技术研究(科学技术类)项目(113013A);教育部创新团队发展计划项目(IRT13047);人事部留学人员科技活动项目(2012001);高等学校学科创新引智计划项目(111 Project;B13007)

摘　　要：为研究Na Cl对红树植物Cd吸收和转运的影响,本文以非泌盐红树秋茄和泌盐红树桐花树幼苗为实验材料,研究了不同浓度Na Cl和Cd Cl2处理下地上和地下各器官中Na+、Ca2+、Cd^(2+)离子浓度的变化,并利用非损伤微测技术测定植物根尖在不同处理下对Cd^(2+)和Ca2+的动态吸收。结果表明,随着Cd Cl2处理浓度的增加,2种红树的根、胚轴、茎和叶4器官中的Cd^(2+)含量均明显增加。而泌盐红树桐花树各器官中Cd^(2+)含量均高于非泌盐红树秋茄,分别达到65%(根)、19%(胚轴)、203%(茎)和96%(叶)。利用非损伤微测技术测定Cd^(2+)流,发现Cd^(2+)内流能被Ca2+通道抑制剂La Cl3抑制,表明Cd^(2+)主要通过Ca2+通道实现内流。在Na Cl对Cd^(2+)吸收的影响方面,低浓度Na Cl(100~200 mmol/L)能促进秋茄对Cd^(2+)的积累,但高浓度Na Cl(400 mmol/L)抑制了桐花树和秋茄对Cd^(2+)的吸收。这是由于:1)红树根系对Na+吸收增加,而Na+能与Cd^(2+)竞争膜上转运蛋白上的金属离子结合位点从而减少Cd^(2+)的吸收,2)Na Cl促进了植物根尖对Ca2+的吸收,从而竞争性的抑制了Cd^(2+)通过Ca2+通道的内流,最终减少了2种红树根系对Cd^(2+)的吸收和积累。泌盐红树桐花树Cd^(2+)含量高于非泌盐红树秋茄,表明桐花树根细胞质膜上的转运蛋白与Ca2+通道对Cd^(2+)的吸收能力高于秋茄。To explore the Na Cl effects on Cd2＋uptake and transport in mangrove plants,Na＋,Ca2 ＋,Cd2＋accumulation in shoot and roots,and root Ca2 ＋and Cd2＋dynamic flux were examined in 3-month-old seedlings of the secretor mangrove Aegiceras corniculatum and non-secretor mangrove Kandelia obovate under Na Cl and Cd Cl2 stress. The results show that Cd2＋content in roots,hypocotyl,stems,and leaves significantly increased with the increase of Cd Cl2 concentrations,in the two mangrove species. The Cd content in different organs of the secretor mangrove A. corniculatum was higher than in that of the nonsecretor mangrove K. obovate,reaching 65%（ root）,19%（ hycopotyl）,203%（ stem）,and 96%（ leaf） respectively. Using the non-invasive micro-test technique,the Cd2＋influx in roots upon Cd Cl2 stress was observed in two mangroves. Furthermore,the Cd Cl2-elicited Cd2＋influx was strongly inhibited by lanthanum chloride（ La Cl3）,a specific inhibitor of calcium channels. This indicates that Cd2＋enters root mainly through the calcium plasma membrane（ PM） channels. We also examined the influence of Na Cl on Cd2＋uptake. Low Na Cl（ 100- 200 mmol / L） was found to increase the Cd2＋uptake and accumulation,but a high Na Cl（ 400 mmol / L） reduced the Cd2＋uptake in the two mangrove species.The possible explanations are： 1） Under Na Cl treatment,the uptake of Na＋was increased by the root ofmangrove. Thus,Na＋competed for metal-binding sites with Cd2＋in the PM transporters. As a result,the Cd2＋uptake was reduced in the two mangrove species. 2） Na Cl increased Ca2 ＋influx under Na Cl stress. This would inhibit the entry of Cd2＋through calcium channels,leading to a declined Cd2＋entry and accumulation in mangrove roots. Cd2＋accumulation in the secretor mangrove A. corniculatum was higher than the non-secretor mangrove K. obovate,indicating that the PM transporters and Ca2 ＋channels in A. corniculatum roots had a high capacity for Cd2＋uptake under Na Cl and cadmium stress.

关 键 词：秋茄 桐花树 离子流 钙离子通道 盐胁迫 镉胁迫 

分 类 号：S718.43[农业科学—林学]