蕹菜吸收和积累Cd和Pb能力的品种间差异

摘要

选育和利用在受污染的土壤中可食部位污染物含量达到食品卫生标准的农作物品种,即污染对策品种(pollution-safe cultivar,简称PSC),是降低污染物经食物链危害人类健康的有效手段.该研究以蕹菜为对象,通过盆栽试验研究了Cd、Pb胁迫下不同蕹菜品种对Cd和Pb吸收积累的差异并探讨了筛选镉、铅污染对策品种(Cd+Pb-PSC)的可行性.结果表明:①与对照相比,无论是Cd还是Pb胁迫,均未引起蕹菜茎叶生物量的显著下降,相反促进了大部分品种茎叶生物量的增加,表明蕹菜对土壤Cd和Pb胁迫有一定的耐性,这可能掩盖土壤受Cd和Pb污染的情况而增加蕹菜受Cd和Pb污染的风险;②在Cd、Pb胁迫下,供试蕹菜品种茎叶Cd、Pb含量品种间差异均达到极显著(P<0.01),且第一茬与第二茬的茎叶Cd、Pb含量分别呈显著(P<0.05)和极显著(P<0.01)相关;③在供试品种中,有2个品种既是Cd-PSC又是Pb-PSC,可看作Cd+Pb-PSC.这表明蕹菜茎叶吸收积累Cd和Pb的特性具有可再现性,受遗传基因控制,因而选育Cd+Pb-PSC是可行的.%In order to reduce the risk of pollutants entering the human diet from soils via agricultural products, breeding of pollution-safe cultivars ( PSCs), that is, the cultivars whose edible parts accumulate specific pollutant at a low enough level for safe consumption when grown in contaminated soil, has been investigated as a practical method of minimizing the concentrations of heavy metals in crops. In this study, a pot experiment is conducted to investigate the variations of Cd and Pb accumulation in different water spinach cultivars. The results show that: ① shoot biomasses of water spinach don't significantly decrease but increase both under Cd and Pb exposure compared with the controls. This indicates that water spinach has a certain degree of Cd and Pb tolerance, which will increase the health risk from water spinach contaminated by soil Cd and Pb. ② shoot Cd and Pb concentrations vary significantly among the tested cultivars under Cd or Pb exposure (P ＜0. 01 ) and correlations of Cd and Pb concentrations of all the cultivars between the first and second harvests are significant at P ＜0. 05 level and at P ＜ 0. 01 level, respectively. ③ The two cultivars, YQ and BGJ, are not only Cd-PSC but also Pb-PSC and may be considered as Cd + Pb - PSC. This implies that the characteristics of Cd and Pb accumulations in water spinach are governed by gene (s) and are able to be well reproduced. Therefore, the selection of Cd + Pb-PSC is feasible in Cd and Pb-contaminated soil.