玉米对铅胁迫的响应及体内铅化学形态研究

通过砂培试验,研究了铅(Pb)胁迫下不同品种玉米根、茎叶中Pb的化学形态变化,进一步探讨玉米耐Pb机制.结果表明,本试验中对Pb胁迫耐性最强的玉米品种为郑单958和隆平206,耐性最差的为联创5号.不同浓度Pb胁迫下玉米根、茎叶中Pb主要以无毒的醋酸提取态和盐酸提取态为主,比例高达60%~87%,这一比例根部略高于茎叶;而活性较强的乙醇提取态和水提取态Pb含量两者合计所占比例为6%~20%.100 mg·L-1Pb胁迫下隆平206茎叶中Pb的乙醇和水提取态合计值最低(0.52 mg·kg-1),其次是郑单958(0.93 mg·kg-1),最高的为联创5号(2.78 mg·kg-1);800 mg·L-1Pb胁迫下,郑单958茎叶中Pb的乙醇提取态和水提取态合计值最低,为2.41 mg·kg-1,因此郑单958耐Pb,可能与体内有毒形态Pb向无毒形态Pb的转换有关.

Response of Maize to Lead Stress and Relevant Chemical Forms of Lead

A sand-culture experiment was carried out to research the differences in lead (Pb) chemical-form among different maize varieties for roots and shoots under Pb stress, and further investigate into the mechanism of maize endurance to resist Pb. The results showed that the wheat varieties of Zhengdan 958 and Longping 206 have the maximum Pb tolerance, whereas Lianchuang 5's tolerance of Pb was the minimum. Pb form in roots and shoots were mainly harmfulness HAc-extractable and HCl-extractable, accounting for a high proportion of 60%-87%. Moreover, these values in roots were slightly higher than those in shoots. And concentrations of alcohol-extractable and water-extractable Pb accounted for the proportion of 6%-20%. Under 100 mg ·L^-1 Pb stress, the alcohol-extractable together with water-extractable Pb content in shoots of Longping 206 was the lowest (0.52 mg ·kg^-1), and that of in Zhengdan 958 shoots was 0.93 mg ·kg^-1 which was also very low. However, for Lianchuang 5, the content could reach 2.78 mg ·kg^-1. Under the stress of 800 mg ·L^-1 Pb, content of alcohol-extractable together with water-extractable Pb in Zhengdan 958 shoots was 2.41 mg ·kg^-1, which was still the lowest. These were probable reasons why Zhengdan 958 was more resistant to Pb stress than other varieties. Tolerance of Zhengdan 958 to Pb stress was related to it's strong ability to convert toxic Pb into non-toxic Pb.