续断菊与玉米间作系统不同植物部位Cd、Pb分配特征

Distribution Characteristics of Pb and Cd in Different Parts of Sonchus asper and Zea mays in An Intercropping System

采用植物修复的方法对会泽铅锌矿周围受Cd、Pb污染的农用地进行修复,将超富集植物续断菊和农作物玉米在污染农用地间作种植,以减少农用地重金属含量,并获得合格的农产品。通过田间小区直接种植的方式,测定植物生物量及各器官重金属含量,研究续断菊(Sonchus asper L.Hill)与玉米(Zea mays L.)间作系统植物不同器官Cd、Pb分配特征。结果表明,(1)间作续断菊生物量相比单作增加了31.55%,间作玉米生物量相比单作增加了29.02%。(2)从拔节期到成熟期,间、单作玉米各器官Cd质量分数呈下降趋势。成熟期与拔节期相比,间作玉米根、茎、叶Cd质量分数分别降低了24.51%、29.06%、55.32%,单作玉米根、茎、叶Cd质量分数分别降低了22.05%、7.20%、45.02%。在不同时期,间作玉米根、叶Cd质量分数都低于单作玉米根、叶Cd质量分数。根部Cd质量分数在抽穗期和成熟期差异显著;叶部Cd质量分数在成熟期差异性显著;茎部Cd质量分数在抽穗期和成熟期呈现出单作大于间作,在成熟期差异显著。玉米各部位Pb质量分数呈现出先增加后下降趋势,且成熟期根、茎Pb质量分数小于拔节期,而该期叶Pb质量分数则大于拔节期。不同时期,间作玉米根、叶Pb质量分数小于单作玉米根、叶,根在抽穗期和成熟期Pb质量分数差异性显著;间作玉米籽粒Cd、Pb质量分数显著小于单作。(3)续断菊根部及地上部Cd质量分数随时间推移而呈现逐渐增加趋势,间作续断菊根部及地上部Cd质量分数分别增加16.88、15.45 mg·kg-1,单作续断菊根部及地上部Cd质量分数分别增加5.5、10.09 mg·kg-1,间作续断菊地上部Cd质量分数显著大于单作,间作根部大于单作根部,在抽穗期和成熟期出现显著差异。(4)间作、单作种植模式下土壤Cd、Pb质量分数均有下降,土壤Cd质量分数在间作模式下降25.99%,单作续断菊模式下降23.19%,单作玉米模式下降14.78%;土壤Pb质量分数在间作模式下降6.78%,单作续断菊模式下降7.53%,单作玉米模式下降7.23%。结果表明,续断菊和玉米间作促进了续断菊各部位对镉的积累量,同时抑制了玉米各部位镉的积累量。

This experiment was to use the method of phytoremediation to repair the polluted farmland by Cd and Pb around lead-zinc mine area in Huize. Hyperaccumulator compositae （Sonchus asper L.Hill） and maize （Zea maysL.） were intercropped in polluted farmland, expecting to not only reduce the heavy metal pollution in soil but also obtain qualified agricultural products. By field plot experiments , plant biomass and heavy metal contents in different organs were determined and we studied the plants on Pb, Cd distribution characteristics in different organs under intercropping system of maize and compositae. The results indicated that： （1） The biomass of intercropping compositae was increased by 31.55% than the monoculture and the biomass of intercropping maize was increased by 29.02% than the monoculture. （2） From jointing stage to maturity stage, the mass fraction of Cd in all organs of maize was decreased by monoculture or intercropping. The Cd mass fraction in roots, stems and leaves by intercropping maize was decreased by 24.51%,29.06%,55.32%. The Cd mass fraction in roots, stems and leaves by monoculture maize was decreased by 22.05%,7.20%,45.02%. In different periods, the Cd contents of roots and leaves by intercropping maize were lower than the monoculture. The Cd content of roots showed significant difference at heading stage and maturity stage. The Cd content of leaves was significant difference at maturity stage. The Cd content of stems at heading stage and maturity stage in monoculture was higher than the intercropping and had significant difference at maturity stage. The Pb mass fraction in all organs of maize increased firstly, and then decreased and the Pb mass fraction in roots and stems at maturity stage was lower than the jointing stage and the Pb mass fraction of leaves at the maturity stage was higher than the jointing stage. In different periods, the Pb contents of roots and leaves by intercropping maize were lower than the monoculture. The Pb content of roots at heading stage and maturity stage had significant difference. The Cd and Pb contents of maize grain were significantly lower than that of monoculture. （3） The Cd mass fraction of the compositae increased with the time passing and the Cd content of overground plant part by intercropping was significantly higher than the monoculture. At heading stage and maturity stage, the Cd content of roots by intercropping was significantly higher than the monoculture. The Cd mass fraction of roots and overground plant part by intercropping increased by 16.88, 15.45 mg·kg^-1, respectively. The Cd mass fraction of roots and overground part under monoculture increased by 5.5, 10.09 mg·kg^-1,respectively. （4） The Cd and Pb mass fraction in soil was decreased, both monoculture and intercropping. It decreased by 25.99% under intercropping. It decreased by 23.19% under monoculture compositae and 14.78% under monoculture maize. The Pb mass fraction in soil decreased by 6.78% under intercropping, and 7.53% under monoculture compositae and 7.23% under monoculture maize. The results showed that compositae and maize intercropping systems not only promoted Cd accumulation of all organs of compositae but also inhibited Cd accumulation of all organs of maize.