Physiological mechanism of hypertolerance of cadmium in Kentucky bluegrass and tall fescue: Chemical forms and tissue distribution
Physiological mechanism of hypertolerance of cadmium in Kentucky bluegrass and tall fescue: Chemical forms and tissue distribution
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DOI：
10.1016/j.envexpbot.2013.09.001
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发表时间：
2013-12
影响因子：
5.7
通讯作者：
Peixian Xu;Zhaolong Wang
中科院分区：
文献类型：
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作者：
Peixian Xu;Zhaolong Wang
草地早熟禾和高羊茅是对土壤镉污染高度耐受的牧草。关于它们的耐受机制的信息很少。设计了砂培和水培实验，研究了镉的化学形态变化及其在不同组织中的转移。结果表明，草地早熟禾和高羊茅在不损失地上部生物量的情况下，可耐受土壤Cd胁迫50~200m g/kg−1，地上部Cd累积量分别高达4275和2559m g/kg−1DW。它们对Cd的耐性与两种草种叶片中未溶Cd磷酸盐的增加有关，这是通过连续的溶剂提取程序来确定的。高羊茅对早熟禾较强的耐镉能力与Cd向根中柱的转运和向叶片的转运较少有关。果胶和蛋白质结合形式的Cd可能参与了Cd从皮层到中柱的共生运输，这可能是导致草地早熟禾根部中柱中Cd含量较高，进而导致地上叶中Cd含量较高的原因。
Kentucky bluegrass (Poa pratensis) and tall fescue (Festuca arundinacea) are hypertolerant grasses to soil cadmium contamination. Little information is available on their tolerance mechanism. A sand culture and a hydroponic culture experiment were designed to investigate the Cd chemical form changes and its translocation in different tissues. The results showed that Kentucky bluegrass and tall fescue can tolerate 50–200 mg kg−1of soil Cd stresses and accumulate as high as 4275 and 2559 mg Cd kg−1DW, respectively, in their shoots without the loss of shoot biomass. Their Cd hypertolerance was correlated with an increase of the undissolved Cd phosphates in the leaves in both grass species, as determined by sequential solvent extraction procedures. The superior Cd tolerance of tall fescue to Kentucky bluegrass was associated with less Cd translocation into the stele of roots and less Cd transported to leaves. The pectate- and protein-integrated Cd forms may be involved in the symplastic translocation of Cd from cortex into stele, and this may lead the higher Cd concentrations in the stele of roots and then above ground leaves via long-distance transport in Kentucky bluegrass.