不同中国鹅掌楸种源对镉吸收分配特性研究

Characteristics of Cadmium Absorption and Distribution in different provenances of Liriodendron chinense

【目的】基于鹅掌楸属植物对重金属污染土壤的修复潜力,研究不同中国鹅掌楸种源根系、茎干、叶片对镉的吸收、转运特性,筛选耐镉能力强、吸收累积镉浓度最高的中国鹅掌楸品种,为镉污染土壤的植物修复提供参考。【方法】在水培条件下,比较7个中国鹅掌楸种源(分别来自云南金平YNJP、云南麻栗坡YNMLP、云南河口YNHK、贵州剑河GZJH、贵州松桃GZST、贵州道真GZDZ、浙江遂昌ZJSC)植株对重金属元素镉的受损伤表型,在镉浓度为10 mg/L条件下,取胁迫15 d后测定根、茎、叶中的镉浓度,计算Cd2+的吸收、转运系数。【结果】镉对中国鹅掌楸不同种源植株的伤害存在显著差异,利用镉胁迫指数评价其受伤害的程度由大到小依次为GZDZ、YNJP、YNHK、YNMLP、ZJSC、GZJH和GZST。中国鹅掌楸种源植株中的Cd2+主要富集在根系中,根系中镉浓度范围为87.09~387.54 mg/kg,茎干镉浓度范围为25.60~71.09 mg/kg,叶片镉浓度范围为5.12~55.94 mg/kg,其中,YNHK和YNJP种源植株对镉的吸收富集能力较强,根茎叶中的镉浓度显著高于其他种源。所有种源镉转运系数均小于1,GZST种源转运系数最高(0.58),但同样来源贵州地区的GZDZ(0.28)和GZJH(0.25)等种源转运系数相对较低。【结论】7个中国鹅掌楸种源主要将吸收的镉固定在根系中,向地上部分的转移较少;GZST种源对镉抗性较强,且地上部分转运富集Cd2+能力最大。

[Objective]Based on the phytoremediation potential of Liriodendron on heavy metal contaminated soil,to select the provenances with strong Cd tolerance and highest Cd2+concentration in seedlings,the characteristics of Cd2+absorption and distribution in roots,stems,and leaves in 7 provenances of Liriodendron chinese were investigated,which could provide a basis for phytoremediation of Cd polluted soil.[Method]The damaged phenotypes were assessed,the Cd concentrations in roots,stems,and leaves in 7 provenances of Liri⁃odendron Chinese were detected after 15 d of exposure to 10 mg/L CdCl2 under hydroponic condition,and the contribution rates of cadmium transportation in different tissues were calculated.[Result]The seedlings from different provenances exhibited significant difference in the injured phenotypic characteristics,and the order of the degrees of Cd injured indexes was:GZDZ>YNJP>YNHK>YNMLP>ZJSC>GZJH>GZST.Cd was mainly accumulated in the roots of the seedings with a range from 87.09 mg/kgto 387.54 mg/kg.The Cd concentration in the stems was detected at a range from 25.60 mg/kgto 71.09 mg/kg,and the range of Cd concentration in the leaves was from 5.12 mg/kgto 55.94 mg/kg.The seedings from YNHK and YNJP showed higher cadmium accumulation than those from other provenances.The transport coefficients of Cd2+of all the provenances were less than 1,which indicated that less Cd was transferred from the root to the aboveground parts(stem and leaf).[Conclusion]Cadium was mainly enriched in the roots in the 7 provenances of Liriodendron chinese,and less in leaves.Furthermore,the seedings from GZST provenance had the highest transport coefficient and the lightest phenotypic damaged characteristics,which could be used to reduce the cadmium content and restore Cd polluted soil.