Abstract

Aims

Soil lead contamination has become increasingly serious and phytoremediation can provide an effective way to reclaim the contaminated soils. This study aims to examine the growth, lead resistance and lead accumulation of mulberry (Morus alba L.) seedlings at four levels of soil lead contamination with or without biochar addition under normal or alternative partial root-zone irrigation (APRI).

Methods

We conducted a three-factor greenhouse experiment with biochar (with vs. without biochar addition), irrigation method (APRI vs. normal irrigation) and four levels of soil lead (0, 50, 200 and 800 mg·kg⁻¹). The performance of the seedlings under different treatments was evaluated by measuring growth traits, osmotic substances, antioxidant enzymes and lead accumulation and translocation.

Important Findings

The results reveal that mulberry had a strong ability to acclimate to soil lead contamination, and that biochar and APRI synergistically increased the biomass and surface area of absorption root across all levels of soil lead. The seedlings were able to resist the severe soil lead contamination (800 mg·kg⁻¹ Pb) by adjusting glutathione metabolism, and enhancing the osmotic and oxidative regulating capacity via increasing proline content and the peroxidase activity. Lead ions in the seedlings were primarily concentrated in roots and exhibited a dose–effect associated with the lead concentration in the soil. Pb, biochar and ARPI interactively affected Pb concentrations in leaves and roots, translocation factor and bioconcentration. Our results suggest that planting mulberry trees in combination with biochar addition and APRI can be used to effectively remediate lead-contaminated soils.

中文翻译：

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生物炭和部分根区交替灌溉大大提高了桑树在修复铅污染土壤中的有效性

摘要

目的

土壤铅污染已经变得越来越严重，而植物修复可以提供一种有效的方法来回收受污染的土壤。这项研究的目的是在正常或替代部分根区灌溉（APRI）下，在有或没有添加生物炭的情况下，在四种土壤铅污染水平下研究桑树（Morus alba L.）幼苗的生长，铅抗性和铅积累。

方法

我们进行了一个三因素温室试验，包括生物炭（添加或不添加生物炭），灌溉方法（APRI与正常灌溉）和四种土壤铅水平（0、50、200和800 mg·kg ^-1）。通过测量生长性状，渗透物质，抗氧化酶以及铅的积累和转运来评估不同处理条件下幼苗的性能。

重要发现

结果表明，桑树具有很强的适应土壤铅污染的能力，并且生物炭和APRI协同增加了土壤铅在所有水平上的生物量和吸收根的表面积。幼苗能够抵抗严重的土壤铅污染（800 mg·kg ^-1Pb）通过调节谷胱甘肽的代谢，并通过增加脯氨酸含量和过氧化物酶活性来增强渗透和氧化调节能力。幼苗中的铅离子主要集中在根部，并表现出与土壤中铅浓度相关的剂量效应。铅，生物碳和ARPI交互影响叶和根中的铅浓度，转运因子和生物浓度。我们的结果表明，结合生物炭和APRI种植桑树可以有效地修复铅污染的土壤。