水分和铅胁迫对槐树幼苗渗透调节物质的影响

Effects of water and lead stress on organic osmotic adjustment substance in the seedlings of two types of pagoda trees

【目的】比较西北干旱、半干旱地区常见造林树种刺槐(Robinia pseudoacacia)和紫穗槐(Amorphafruticosa)对重金属铅的耐受性,为干旱半干旱地区重金属铅污染土壤的修复提供依据。【方法】采用盆栽试验,对1年生刺槐和紫穗槐幼苗进行水分胁迫(土壤相对含水率分别为100%,80%,60%,40%)和铅胁迫(土壤铅含量分别为0,300,500,1 000,2 000,3 000mg/kg)处理,分析在水分和铅单一及交互胁迫条件下,2种植物叶片有机渗透调节物质含量的变化。【结果】刺槐和紫穗槐叶片脯氨酸、可溶性糖、可溶性蛋白含量随水分和铅胁迫程度的加剧而呈现复杂的变化规律。单一水分胁迫下,刺槐叶片脯氨酸含量的变化幅度高于单一铅胁迫,当土壤铅含量相同时,土壤相对含水率为40%的处理脯氨酸含量显著高于其他水分胁迫处理;在铅或水分单一胁迫及二者的交互胁迫中,当土壤铅含量相同时(土壤铅含量为3 000mg/kg处理除外),各水分胁迫处理的刺槐叶片可溶性糖含量差异不显著(P>0.05)。在单一水分或铅胁迫条件下,刺槐、紫穗槐叶片可溶性蛋白含量均未随胁迫程度的加剧而降低。【结论】水分和铅交互胁迫条件下,脯氨酸对提高刺槐和紫穗槐抗旱性的贡献大于抗铅性;刺槐积累脯氨酸提高自身抗逆性的能力强于紫穗槐,而紫穗槐合成可溶性蛋白和可溶性糖提高自身抗逆性的能力强于刺槐。

【Objective】 The study was conducted with the purpose of comparing the tolerance of lead to two common drought-enduring trees in northwest China,Robinia pseudoacacia and Amorpha fruticosa,and provided a basis for phytoremediation of soil contaminated by lead in arid and semi-arid regions.【Method】 One-year old seedlings were planted in containers under 6 different lead treatments（soil Pb content 0,300,500,1 000,2 000,3 000 mg/kg,respectively） and 4 water treatments（relative soil water content 100%,80%,60%,40%,respectively）.The contents of organic osmotic adjustment substances in the leaves were determined under water,Pb stress and water and Pb interaction stress.【Result】 With the increase of stress level,the changes of Pro,soluble sugar（SS） and soluble protein（SP） content of the two types of trees were complicated.The Pro content in the leaves of R.pseudoacaciawere under water stress was larger than under Pb stress,and when the relative soil water content was 40%,at the same soil Pb content level,the Pro contents in the leaves of R.pseudoacacia were significantly higher than under other relative soil water contents.Under Pb or water stress or interaction,at the same soil Pb content（except for 3 000 mg/kg）,the SS contents in the leaves of R.pseudoacacia under different water stress treatments had no significant difference（P0.05）.Under water or Pb stress,as the stress level increased,the SP contents in the leaves of R.pseudoacacia did not decrease,so did A.fruticosa.【Conclusion】 The contribution of Pro to raise the resistance to water was stronger than to Pb.R.pseudoacacia＇s accumulation ability of Pro to raise the resistance to water and Pb stress was stronger than A.fruticosa＇,vice vercer.A.fruticosa＇s production of SS and SP to raise the resistance to water and Pb stress was stronger than R.pseudoacacia＇.