籽粒苋对土壤中镉的耐性和积累特征

Tolerance and Accumulation of Cadmium in Soil by Amaranthus hypochondriacus L.

籽粒苋是一种生物量大、易栽培的镉(Cd)富集植物,具有作为Cd污染土壤修复植物的潜力.比较了两个基因型籽粒苋(K112和R104)的耐Cd性特征,土壤Cd污染浓度范围是0～50mgkg-1,生长60d收获.结果表明,籽粒苋K112(Amaranthus hypochondriacus L. Cv.‘K112’)与R104(A. hypochondriacus L. Cv.‘R104’)生物量随土壤中Cd浓度的增加而逐步下降,在土壤中Cd浓度<16mgkg-1时,其生物量积累没有受到明显的影响.在本试验最高Cd浓度条件(50mgkg-1)下仍可生长,但生物量显著下降.两种籽粒苋叶中Cd含量随土壤中Cd浓度增加而快速上升,在土壤Cd浓度为16mgkg-1时,叶内Cd浓度分别达120.63和109.96mgkg-1(DW),达到超富集植物的临界标准.Cd在植物体内的分布特征为叶>根>茎.籽粒苋两个品种相比,K112吸收Cd的能力大于R104,尤其是在高Cd浓度时,两种籽粒苋对Cd的绝对提取量相似,并随土壤Cd浓度的上升而快速增加.籽粒苋K112和R104对土壤中的Cd具有很强的耐性和积累的能力,可作为Cd污染土壤的修复植物.

Amaranthus hypochondriacus L.is an easily cultivated and high-biomass plant which could uptake and accumulate high level of cadmium（Cd） from polluted soil.Two hybrid clones（A.hypochondriacus L.Cv.＇K112＇ and A.hypochondriacus L.Cv.＇R104＇） were tested for their capability of Cd tolerance and accumulation in a 60 days greenhouse pot experiment.The Cd concentration in the tested soil ranged from 0 to 50 mg kg-1.The results indicated that the biomass of the two clones declined with the increasing of Cd concentration in soil.The soil with Cd concentration lower than 16 mg kg-1 did not restrain the growth of the two tested plants.At the highest Cd concentration（50 mg kg-1） in soil,the both clones were still alive,but produced very low biomass.The Cd concentration in leaves markedly increased at the Cd concentration in soil from 0 to 50 mg kg-1.When growing in the soil with 16 mg kg-1 Cd,the Cd concentrations in the leaves of the two plants were up to 120.63 mg kg-1 and 109.96 mg kg-1,respectively,which were larger than the threshold as Cd hyperaccumulator（100 mg kg-1）.The Cd concentrations in diferent parts of the plants with in the order of leaf root stem.The Cd concentration in the leaves of K112 was higher than that of R104,especially growing in the soil with high Cd concentration.The total quantities of Cd uptake by K112 and R104 were similar,but sharply increased with the increasing of Cd concentration in soil.K112 and R104 are two promising plants for phytoremediation because of their high Cd accumulation capacity and high biomass yield.