重金属胁迫对小麦生长的影响及阈值研究

摘要

以当前农业研究的热点领域-重金属污染为切入点,研究大田环境下Cd、Pb、As、Hg、Cr这5种重金属对郑麦9023、小偃22的株高、穗长及产量等生长因子的影响.结果表明,Cd、Pb、As、Hg、Cr胁迫对郑麦9023的穗长及As、Cd、Cr胁迫对小偃22的穗长均表现出抑制效应；而Hg、Pb胁迫对小偃22的穗长表现为促进效应.与对照相比,5种重金属对小偃22的株高均表现为抑制作用；而As、Hg胁迫对郑麦9023的株高则表现为促进作用,Cd、Pb胁迫则表现为“高促低抑”的特点,Cr胁迫表现为“低促高抑”趋势.此外,5种重金属胁迫下,只有重金属Cr胁迫显著降低了2个小麦品种的籽粒产量,而Cd、Hg、Pb、As胁迫则没有表现出抑制现象.通过对重金属胁迫浓度与产量的拟合分析,得出As、Cd、Cr、Hg、Pb这5种重金属对郑麦9023的产量阈值分别为53.42,1.31,749.73,7.43,555.57 mg/kg,对小偃22的产量阈值分别为42.58,1.80,828.18,10.30,437.01 mg/kg.表明郑麦9023抗As、Pb胁迫能力较强,而小偃22抗Cd、Cr、Hg胁迫的能力相对较强.%The plant height, spike length and grain yield of wheat varieties Zhengmai 9023 and Xiaoyan 22 were analyzed under the stress of heavy metals Cd.Pb, As, Hg,and Cr in field conditions. The results showed that the spike length of Zhengmai 9023 decreased under the stress of Cd.Pb,As,Hg and Cr,and the similar results in Xiaoyan 22 were also found under the stress of Cd, As and Cr. The plant height of Xiaoyan 22 reduced under the stress of Cd,Pb,As,Hg and Cr,but it increased in Zhengmai 9023 under the stress of As and Hg. The plant height increased with the higher dose of Cd and/or Pb and decreased with the lower dose of Cd and/or Pb, but showed a reverse trend under Cr stress. In addition,the grain yield of the two varieties was significantly lower under Cr stress than CK,but was higher under Cd,Pb,As and Hg stress. The yield threshold value of As,Cd,Cr,Hg and Pb was 53.42,1.31,749.73,7.43,555.57 mg/kg for Zhengmai 9023 respectively, and 42.58,1. 80,828. 18,10. 30, 437. 01 mg/kg for Xiaoyan 22 respectively.