提高供磷可缓解砷对番茄的胁迫作用  

EFFECT OF HIGHER PHOSPHATE SUPPLY LESSENING As STRESS ON TOMATO

作　　者：王萍[1] 胡江[1] 冉炜[1] 徐国华[1] 

机构地区：[1]南京农业大学资源与环境科学学院,南京210095

出　　处：《土壤学报》2008年第3期503-509,共7页Acta Pedologica Sinica

基　　金：国家自然科学基金项目(批准号30471037);江苏省基础研究计划(批准号BK2005089);高等学校博士学科点专项科研基金(20040307037)资助

摘　　要：环境和食品中砷标准提高后，砷污染及其有关的食品安全问题更加受到广泛的关注。磷对植物吸收和累积砷的影响及其作用机制仍有很大争论。本文利用水培试验，研究了0．025～1．0mmol L^-1范围内7个供磷水平下50μmol L^-1 AsO4^3-胁迫对微型番茄生长、砷和磷的吸收及两个磷酸盐转运体基因（LePTl和LePT2）表达的影响。在0．025～0．4mmol L^-1的缺磷条件下，砷对番茄的生长有明显抑制作用。在缺磷状态下，增加磷供应能显著减少番茄体内砷的浓度。约58％的砷累积在番茄根部，根部砷的浓度较地上部高10倍以上。砷抑制番茄对磷的吸收只出现在严重缺磷（0．025～0．05mmol L^-1）条件下。此外，外界砷的存在对LePT1、LePT2基因的表达影响不显著。从本文的结果来看，番茄吸收过程中的磷砷相互作用在缺磷条件下更明显，提高供磷水平可降低番茄体内砷含量，缓解砷对番茄的胁迫作用。Following the promulgation of the standards for arsenic （As） in environment and food people are getting more and more concerned about As pollution and the issue of food safety. It is still controversial over effect of phosphorus （P） supply on uptake and accumulation of As in plant and its mechanism. A hydroponic experiment of tomato （ Lycopersicon esculentum, cv. Micro-tom） was conducted to verify the effect of P mitigating As stress on plant growth. Addition of 50 μmol L^-1 arsenate （AsO4^3- ） significantly decreased the growth of both root and shoot of the tomato plant with P supply ranging from 0.025 to 0.4 mmol L^-1, however, both As concentration in the plant and its inhibitory effect were reduced as P supply rose in level. The roots contained much more As than the shoots. Inhibitory effect of As on P uptake was observed also .only at low P supply levels （0.025 and/or 0.05 mmol L^-1 of P） . In addition, As had little influence on the expression of the two phosphate transporter genes （ LePT1 and LePT2 ） in tomato. In conclusion, increase in P supply could decrease concentration of As in the plant, thus mitigating the adverse effects of As stress on tomato growth.

关 键 词：磷酸盐 磷转运体基因 砷酸盐 吸收 胁迫 番茄 

分 类 号：S181[农业科学—农业基础科学]