外源锌对铬胁迫下烤烟锌、铬积累和多酚类物质的影响

【目的】探究不同锌（Zn）浓度对铬（Cr）胁迫下烤烟Cr和Zn积累及烟叶多酚类物质的影响，为烤烟种植过程中重金属污染的防治及修复提供理论依据。【方法】采用盆栽试验，以不添加Zn和Cr为对照，设不同浓度单一Zn（20、60和100 mg/kg）及Zn+C（rCr为15、30和90 mg/kg）复合处理。在烟苗移栽后50和80 d，取7～11叶位的烟叶用于测定烟叶的绿原酸、莨菪亭和芦丁含量；80 d时另取根、茎、叶3个部位测定烟株生物量、Cr和Zn的吸收量，所得数据进行差异显著性检验、双因素方差分析和Pearson相关分析。【结果】单一Zn处理下，烟株生物量随Zn浓度增加呈先升后降的变化趋势，其中60 mg/kg处理的生物量最高，根、茎、叶分别比对照增加28.1%、14.5%和7.4%。Zn和Cr复合作用下，15 mg/kg Cr与Zn复合处理的烟株生物量与对照相差较小，而90 mg/kg Cr浓度下的烟株生物量均低于对照。单一Zn处理对烟株根部的Cr吸收具有低促高抑效应，且降低烟叶Cr富集、促进烟叶Zn积累。Zn和Cr复合处理增加烟株根部Cr积累、降低Zn积累，同时烟叶Cr含量均低于对照，降幅范围为41.9%～72.7%，而烟叶Zn含量除15 mg/kg Cr与Zn复合处理外均低于对照。外源添加Zn能降低烟叶Cr的生物累积系数（BAF），除0、15 mg/kg Cr和100 mg/kg Zn复合处理外，其余处理茎叶/根的位移系数（TF）均低于对照。单一Zn处理能促进烟叶绿原酸、芦丁和莨菪亭积累。Cr和Zn复合处理下，土壤Zn/Cr添加比例为20/15、60/15和100/15时能促进烟叶绿原酸和芦丁的积累。【结论】添加外源Zn能降低Cr在烟叶中的积累，土壤Zn/Cr添加比例高时能促进烟叶中Zn、绿原酸和芦丁的积累，抑制根中Cr积累。可考虑通过添加Zn元素调节土壤中Cr、Zn比例以降低烟叶中Cr含量和调控烟叶中多酚物质积累。

Effects of exogenous zinc on the accumulation of zinc and chromium and polyphenols in flue-cured tobacco under chromium stress

【Objective】This study was to explore the effects of different zinc(Zn) concentrations on the accumulation of chromium(Cr), Zn and polyphenols in flue-cured tobacco under Cr stress, so as to provide theoretical basis for the prevention and remediation of heavy metal pollution in flue-cured tobacco planting.【Method】Employing the pot experiment to simulate the single Zn(20, 60 and 100 mg/kg) pollution and the contamination treatment of Znand Cr(Cr was 15, 30 and 90 mg/kg), the treatment without adding Zn and Cr was selected as the control.On the 50th day and 80th day after transplanting, tobacco leaves of the 7 to 11 leaf positions were taken to determine the contents of chlorogenic acid, scopoletin and rutin;on the 80th day after transplanting, the biomass, Cr and Zn absorption of tobacco plants were determined from three parts of tobacco(root, stem, leaf), the data were analyzed by significance test, two-way ANOVA and Pearson correlation analysis.【Result】Under single Zn stress, the biomass of tobacco plants increased firstly and then decreased with the increase of Zn concentration.The biomass of 60 mg/kg Zn treatment was the highest, and the roots, stems and leaves biomass increased by 28.1%, 14.5% and 7.4% respectively compared with the control.Under the Zn and Cr combined pollution, the biomass of tobacco plants treated with 15 mg/kg Cr was not greatly different from that of the control, while the biomass of 90 mg/kg Cr treatments was lower than that of the control.Single Zn had obvious effect of low concentration promoting and high chromium inhibiting the absorption of Cr in the roots of tobacco plants, and reduced Cr contents and promoted Zn accumulation in leaves.Under the combined treatment of Zn and Cr, the accumulations of Cr in tobacco roots was increased and that of Zn was decreased.At the same time, the Cr contents of compound treatments in tobacco leaves were decreased by 41.9%-72.7% compared to control, while the Zn content of tobacco leaves was lower than that of the control except for 15 mg/kg Cr combined with Zn.Exogenous addition of Zn could reduce the tobacco leaf Cr bioaccumulation factor(BAF).Except for the combined treatment of 0 and 15 mg/kg Cr and 100 mg/kg Zn, the stemand leaf/root translocation factor(TF) of the other treatments were lower than the control.Single Zn could promote the accumulation of chlorogenic acid, rutin and scopoletin in tobacco leaves.The soil Zn/Cr addition ratios at 20/15, 60/15, and 100/15 were beneficial to the accumulation of chlorogenic acid and rutin in tobacco leaves under Cr and Zn combined stress.【Conclusion】Adding exogenous Zn can reduce the Cr accumulation in tobacco leaves.The high soil Zn/Cr addition ratios can promote the accumulation of Zn, chlorogenic acid and rutin in the tobacco leaves, and inhibit the accumulation of Cr in the roots.It can be considered to adjust the ratio of Cr and Zn in the soil by adding Zn element to reduce the content of Cr in tobacco leaves and regulate the accumulation of polyphenols in tobacco leaves.