铝、镉胁迫下不同大麦品种根际的铝、镉形态分析

Forms of Aluminum and Cadmium in the Rhizosphere of Two Barley Genotypes with Aluminum Tolerances under Aluminum and Cadmium Stresses

为明确铝(Al)、镉(Cd)单独及复合胁迫下作物根际毒害元素的化学形态及其生物有效性,采用盆栽试验,以耐铝性不同的两个大麦品种(铝敏感品种浙农大9号和耐铝品种Day ten)为试验材料,利用连续提取法和ICP-AES方法分析了拔节期大麦根际的Al、Cd化学形态及其含量。结果表明,所有处理中大麦植株根际溶出Al均主要以毒性较小的酸溶无机Al和腐殖酸Al存在,根际Cd则主要以残留态形式存在。Al、Cd单独胁迫下大麦根际土壤溶液中各形态Al、Cd的溶出量均显著增加,交换态含量占可提取Al、Cd总量的比例增加。其中浙农大9号根际活性Al、Cd含量的增幅均大于Dayton。与单独Al或Cd处理相比,复合胁迫下根际交换态Al和Cd含量增加,其他形态含量下降或变幅不大。

The pot experiment was conducted o identify the chemical forms of aluminum（Al） and cadmium（Cd） and their plant availability in the rhizosphere soil of two barley varieties contrasting in Al tolerance in response to the separate and combined treatments of Al and Cd,sequential extraction and ICP-AES were used as to analyze the contents of Al and Cd in plant rhizosphere soil at jointing stage.The results showed that the major proportions of the extractable Al in rhizosphere of the two varieties were ASI-Al（acid-soluble inorganic） and HA-Al（humic acid）,and the amounts of chemical forms of Al were in the order of ASI-Al HA-Al MH-Al（monomer hydroxyl） Ex（exchangeable）,whereas,Res（residue）-Cd was the most dominant form of extractable Cd in the rhizisphere of both varieties,irrespective of treatments.Al or Cd treatment increased the amounts of all the chemical forms,as well as the proportion of exchangeable forms.Al sensitive variety Zhenongda9 had higher ability to active Al or Cd in rhizosphere than Dayton.Binary metal stress increased the amounts of exchangeable forms of Al and Cd,while did not induce significant changes of other forms as compared with Al or Cd independent treatments.