生态环境学报 ›› 2022, Vol. 31 ›› Issue (8): 1657-1666.DOI: 10.16258/j.cnki.1674-5906.2022.08.018

• 研究论文 • 上一篇    下一篇

湿地植物根系泌氧能力和根表铁膜与根系吸收重金属的关系

李莹(), 张洲, 杨高明, 祖艳群, 李博, 陈建军*()   

  1. 云南农业大学资源与环境学院,云南 昆明 650201
  • 收稿日期:2022-03-22 出版日期:2022-08-18 发布日期:2022-10-10
  • 通讯作者: * 陈建军(1970年生),男,教授,博士,主要研究方向为土壤重金属污染的植物修复。E-mail: chenjianjun94@126.com
  • 作者简介:李莹(1999年生),女,硕士研究生,主要研究方向重金属修复工作。E-mail: liying990125@163.com
  • 基金资助:
    国家重点研发计划重点专项(2018YFC1802603);云南省重点研发计划项目(2019BC001-04)

The Relationship between the Radial Oxygen Loss and the Iron Plaque on Root Surfaces to Wetland Plants Absorb Heavy Metals

LI Ying(), ZHANG Zhou, YANG Gaoming, ZU Yanqun, LI Bo, CHEN Jianjun*()   

  1. College of Resources and Environment, Yunnan Agricultural University, Kunming 650201, P. R. China
  • Received:2022-03-22 Online:2022-08-18 Published:2022-10-10

摘要:

以纸莎草(Cyperus papyrus L.)、鸢尾(Iris tectorum Maxim.)、美人蕉(Canna indica Linn)、香蒲(Typha orientalis Presl)、再力花(Thalia dealbata Fraser)作为供试植物,矿渣土作为底泥进行植物培养试验,研究5种植物根系泌氧(ROL)和根表铁膜对植物吸收重金属的影响及差异,为湿地植物修复重金属污染提供理论。结果表明,5种供试植物在高浓度Cd、Pb、As复合污染下,香蒲的根部特征都表现为促进生长状态,其他4种植物生长均受到抑制作用;5种供试植物的ROL速率均是呈现先增加后降低的趋势,在第40天时香蒲ROL显著高于其他4种植物,因其在Cd、Pb、As复合污染下孔隙度和通气组织的增大使其具有较高的ROL速率;5种供试植物铁膜中Fe含量都呈现为先增加后降低的趋势,在试验第20天,供试植物根表铁膜中Fe质量分数达到最大,美人蕉和香蒲分别为15.63 mg∙kg-1和13.72 mg∙kg-1,显著高于其他3种供试植物;5种供试植物铁膜中Cd、Pb含量都在第10—20天显著上升,后趋于稳定,而As含量则呈持续上升趋势,特别是香蒲和美人蕉根表铁膜中Cd、Pb、As含量显著高于其他3种供试植物;5种供试植物地上部和地下部Cd、Pb、As含量总体都为逐渐上升,其中纸莎草地下部重金属含量较其他4种植物多。通过相关性分析和回归性分析发现,ROL对植物吸收Cd、Pb、As的系数绝对值远大于根表铁膜抑制Cd、Pb、As吸收的系数绝对值,说明ROL对植物吸收Cd、Pb、As促进作用强于根表铁膜对Cd、Pb、As的抑制作用,ROL是作为湿地植物根部吸收重金属最主要的影响因素。

关键词: 湿地植物, 根系泌氧, 根表铁膜, 重金属, 根系孔隙度, 通气组织

Abstract:

Investigation of the effects and differences of plant radial oxygen loss (ROL) and iron plaque on root surfaces on plant uptake of heavy metals provides a theoretical basis for wetland phytoremediation of heavy metal pollution. In this study, five wetland plants (Cyperus papyrus L., Iris tectorum Maxim., Canna indica Linn, Typha orientalis Presl and Thalia dealbata Fraser) and slag soil were used to establish hydroponic experiment. The results showed that the growth of T. orientalis were promoted while the growth of the other four plants was inhibited under the combined pollution of high concentrations of Cd, Pb and As. The ROL rate of the five tested plants increased first and then decreased. On the 40th day of incubation, the ROL of T. orientalis was significantly higher than that of the other 4 plants. Because of the increase in porosity of root and root aerenchyma under the composite pollution of Cd, Pb, and As, T. orientalis had a higher ROL rate. The content of iron plaque on root surfaces of five tested plants showed a trend of increasing first and then decreasing. On the 20th day of incubation, the content of iron plaque on root surfaces of the tested plants reached the maximum. The contents of iron plaque on root surfaces of C. indica and T. orientalis were 15.63 mg∙g-1 and 13.72 mg∙g-1 respectively, which were significantly higher than those of the other three tested plants. The content of Cd and Pb in the iron plaque on root surfaces of the five tested plants increased significantly from 10th to 20th days, and then stabilized. While the content of As in the iron plaque on root surfaces has been increasing, the contents of Cd, Pb and As in the iron plaque on root surfaces of T. orientalis and C. indica were significantly higher than those of the other three tested plants. The content of Cd, Pb and As in the shoot and root of the five tested plants increased gradually, among which the amount of heavy metals in the root of C. papyrus was more than that of the other four plants. The correlation and regression analyses showed that the absolute value of the coefficient of ROL for plant uptake of Cd, Pb, and As was much greater than the absolute value of the iron plaque on root surfaces inhibiting the absorption of Cd, Pb, and As. it suggested that the promoting effect of ROL on plant absorption of Cd, Pb and As was stronger than the inhibitory effect of iron plaque on root surfaces on Cd, Pb and As. ROL might be the most important influencing factor for the absorption of heavy metals by the roots of wetland plants.

Key words: wetland plants, radial oxygen loss, iron plaque on root surfaces, heavy metal, porosity of root, root aerenchyma

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