高子平+王龙+尹洁+崔冠男+王景安+刘仲齐

摘    要：以红樱桃萝卜（Raphanus sativus L.var.radculus pers）为材料，对根际环境中和叶片中的镉（Cd）浓度与Cd在萝卜体内转运积累的关系进行了研究。结果表明：萝卜根部组织中的Cd含量随根际环境中Cd浓度的增加而增加，根部次生韧皮部对Cd的积累量明显大于次生木质部。在高Cd环境中次生木质部中的Cd吸收量与次生韧皮部中的Cd含量呈极显著正相关。萝卜根系次生木质部中Cd积累量与叶柄和叶片中的Cd含量高度正相关，根系中的Cd主要通过次生木质部转运到叶柄和叶片中。叶片中的Cd主要通过次生木质部向根系转运，到达根系向外扩散到次生韧皮部，向内扩散到初生木质部。

关键词：萝卜;镉;木质部;韧皮部;转运

中图分类号：X53               文献标识码：A         DOI 编码：10.3969/j.issn.1006-6500.2015.11.010

Effects of Cadmium Pollutant Sources on the Accumulation Characteristics of Radish

GAO Zi-ping1，2， WANG Long2， YIN Jie1，2， CUI Guan-nan1，2， WANG Jing-an1， LIU Zhong-qi1，2

（1.Tianjin Key Laboratory of Animal and Plant Resistance， College of Life Science， Tianjin Normal University， Tianjin 300387， China; 2.Centre for Research in Eco-toxicology and Environmental Remediation， Agro-Environmental Protection Institute， Ministry of Agriculture， Tianjin 300191， China）

Abstract： Red Cherry Belle Radish（Raphanus sativus L.var.radculus pers）was used to study the relationship between the transport and accumulation of cadmium （Cd）inside radish and Cd content in the rhizosphere environment as well as in leaves. The results showed that the content of Cd in root tissue was increased with the increasing of Cd concentration in rhizosphere environment and Cd content in the secondary phloem was apparently higher than that in the secondary xylem. Cd accumulation in the secondary xylem was significantly and positively correlated with the Cd content in the secondary phloem when radish was planted in high Cd concentration environment. Cd accumulation in the secondary xylem of root tissues was significantly and positively correlated with the Cd content in lamina and petiole organs. Cd in lamina and petiole organs was transferred from root mainly by the secondary xylem. Cd in lamina can also be transferred to root by the secondary xylem， and then diffused to the secondary phloem and primary xylem.

Key words：radish; cadmium; xylem; phloem; transport

镉（Cadmium，Cd）作为一种生物非必需的重金属元素，在环境中的化学活性强，移动性大，毒性持久，被认为是最重要的重金属污染物之一。近年来，工业生产、开矿、汽车排放尾气等使水体、土壤、空气受到严重污染，大量Cd进入土壤-植物生态系统，并通过食物链危及人类健康[1-2]。樱桃萝卜是中国四季萝卜中的一种，是春夏之交广受欢迎的新兴蔬菜之一，具有营养价值高、适应性强等优点。萝卜的主要食用部位是肉质根，而根作为全方位接触土壤环境的器官，能优先吸收并积累土壤中的各种重金属元素和其它离子[3-4]。大气沉降是土壤中Cd积累的重要途径之一，大气中的Cd经自然沉降和雨淋沉降进入土壤，并积累在相应的区域内[5]，也可以被植物吸收并向土壤中传输[6]。……