生态环境学报 ›› 2023, Vol. 32 ›› Issue (1): 158-165.DOI: 10.16258/j.cnki.1674-5906.2023.01.017

• 研究论文 • 上一篇    下一篇

镉与聚乙烯微塑料胁迫对小白菜根系的形态特征和分形维数的影响

崔远远1(), 张征云2, 刘鹏1, 张运春1, 张桥英3,*()   

  1. 1.西华师范大学环境科学与工程学院,四川 南充 637009
    2.天津市生态环境科学研究院,天津 300191
    3.西华师范大学地理科学学院,四川 南充 637009
  • 收稿日期:2022-08-18 出版日期:2023-01-18 发布日期:2023-04-06
  • 通讯作者: *张桥英(1976年生),女,教授,主要从事植物生态与生物地理研究。E-mail: qiaoyingzhang@163.com
  • 作者简介:崔远远(1997年生),女,硕士研究生,研究方向为植物对环境污染物的响应机制。E-mail: 2978996593@qq.com
  • 基金资助:
    科技部第二次青藏高原综合科学考察项目(2019QZKK0304);西华师范大学博士科研启动项目(17E037)

Morphological Characteristics and Fractal Dimension of Brassia chinensis Root System under Cadmium and Polyethylene Microplastic Stress

CUI Yuanyuan1(), ZHANG Zhengyun2, LIU Peng1, ZHANG Yunchun1, ZHANG Qiaoying3,*()   

  1. 1. College of Environmental Science and Engineering, China West Normal University, Nanchong 637009, P. R. China
    2. Tianjin Academy of Eco-environmental Sciences, Tianjin 300191, P. R. China
    3. School of Geographical Sciences, China West Normal University, Nanchong 637009, P. R. China
  • Received:2022-08-18 Online:2023-01-18 Published:2023-04-06

摘要:

根系是植物适应环境条件的重要器官,分形维数是快速准确的评估根系形态特征的有效方法,尤其是在胁迫下评估植物根系对水分和养分吸收及植物生长贡献分析具有重要意义。为探讨重金属镉及聚乙烯微塑料对小白菜根系生长的影响,采用盆栽实验,研究了不同添加质量分数下(镉:0、10、20 mg·kg-1;聚乙烯:0、18、36 g·kg-1)两种污染物对小白菜根系形态的影响。运用根系分析仪的图像分析系统来研究受镉和聚乙烯胁迫90 d的小白菜的根系形态。采用分形分析的方法对小白菜根系进行描述,并确定镉和聚乙烯的添加对根系的分形维数的影响。结果表明,镉和聚乙烯添加会促进根系的分生能力,增加根系的分形维数,同时在不同浓度的镉和聚乙烯胁迫下,小白菜会形成不同的根系构型。在低浓度胁迫下,小白菜通过增加根系比表面积,减小根平均直径和根体积,促进细根发育来适应胁迫环境。在高浓度胁迫下,小白菜通过增加根长、根表面积、比表面积和比根长,增加根尖数,减小根平均直径,促进细根发育来适应胁迫环境。镉和聚乙烯胁迫影响小白菜根系的分形能力,使得分形维数介于1.55—1.70之间变化。镉浓度对分形维数有显著影响,而聚乙烯对分形维数的影响差异性不显著。基本根系形态与分形维数的变化呈正相关,且分形维数对根直径和根体积的影响更大。该研究揭示了在重金属和微塑料胁迫下,植物会通过构建不同的根系构型来适应土壤环境;实验结果还间接证明了微塑料对重金属有一定的吸附作用。

关键词: 镉, 聚乙烯, 小白菜, 分形维数, 根系形态, 根系构型

Abstract:

Root system is an important organ for plant adaptation to environmental conditions. Fractal dimension is an effective method for rapid and accurate assessment of morphological characteristics of root system, which is especially important for the assessment of water and nutrient uptake by plant roots and analysis of plant growth contribution under stress. To investigate the effects of heavy metal cadmium and polyethylene microplastic on the growth of Brassia chinensis, a pot experiment was conducted to study the effects of two contaminants (cadmium: 0,10, and 20 mg·kg-1; polyethylene: 0, 18, and 36 g·kg-1) on the root morphology of B. chinensis. In this experiment, the image analysis of the root analyzer was used to study the root morphology of B. chinensis under cadmium and polyethylene stress for 90 days. Fractal analysis was used to describe the root system of B. chinensis, and the effects of cadmium and polyethylene additions on the fractal dimension of the root system were determined. The results showed that the addition of cadmium and polyethylene would promote the fractal capacity of the root system and increase the fractal dimension of the root system, while different root configurations were formed in B. chinensis under different concentrations of cadmium and polyethylene stress. Under low concentration stress, B. chinensis adapted to the stress environment by increasing the root specific surface area, decreasing the mean root diameter and root volume, and promoting fine root development. Under high concentration stress, B. chinensis adapted to the stress environment by increasing root length, root surface area, specific surface area and specific root length, increasing root tip number, decreasing root mean diameter and promoting fine root development. Cadmium and polyethylene stresses affected the fractal capacity of root systems of B. chinensis, causing the fractal dimension to vary between 1.55 and 1.70. Cadmium concentration had a significant effect on the fractal dimension, while polyethylene concentration had a non-significant effect on it. The basic root morphology was positively correlated with the variation of fractal dimension, and the fractal had a greater effect on root diameter and root volume. This study revealed that plants adapt to soil environment by constructing different root architectures under heavy metal and microplastic stress. This experiment also indirectly proved that microplastics have a certain adsorption effect on heavy metals.

Key words: cadmium, polyethylene, Brassia chinensis, fractal dimension, root morphology, root architecture

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