Background and aims

Vermicompost is a valuable amendment for phytomanagement of heavy metals contaminated areas but its impact on plant physiology remains poorly documented. It is available in liquid or solid forms, but these forms were never compared for their influence on pollutant accumulation by the plant in relation to soil heavy metals bioavailabilities.

Methods

Solid vermicompost (SV) and liquid vermicompost leachate (LVL) were tested on spiked soils in the absence (control) or in the presence of either 10 mg.Kg⁻¹ Cd, 250 mg.Kg⁻¹ Zn or 500 mg.Kg⁻¹ Pb and cultivated with Zygophyllum fabago L. in a column device allowing leachate recovery and analysis. Plant physiological parameters were determined during 10 weeks of culture.

Results

SV reduced soil heavy metals bioavailability, improved plant growth and photosynthesis and reduced heavy metals concentrations in all organs. In contrast, LVL increased heavy metal bioavailability and root growth but inhibited shoot growth. LVL decreased root heavy metals concentrations but increased them in the shoots. Both types of amendments increased the total amount of heavy metal removed by the plant. Among the removed Cd and Zn less than 5% were removed by leaching and SV contributed to reduce percolation. SV contributed to stress avoidance by reducing pollutant uptake while LVL contributed to stress tolerance through reinforcement of endogenous protecting mechanisms.

Conclusions

Both SV and LVL are beneficial amendments for phytostabilization and phytoextraction of heavy metals by Z. fabago but act through distinct mechanisms on the plant in relation to mineral nutrition, oxidative stress and osmotic adjustment.

中文翻译：

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固体蚯蚓堆肥和液体蚯蚓堆肥渗滤液对叙利亚豆螨 Zygophyllum fabago L 提取镉、铅和锌植物的影响截然不同。

 背景和目标

蚯蚓堆肥是重金属污染区植物管理的宝贵修正剂，但其对植物生理学的影响仍然鲜有记录。它以液体或固体形式存在，但从未比较过这些形式对植物污染物积累与土壤重金属生物利用度的关系。

 方法

固体蚯蚓粪 （SV） 和液体蚯蚓堆肥渗滤液 （LVL） 在没有（对照）或存在 10 毫克的加标土壤上进行了测试。公斤^-1 镉，250 毫克。^Kg-1 Zn 或 500 mg。^Kg-1 Pb 并在柱装置中与 Zygophyllum fabago L. 一起培养，允许渗滤液回收和分析。在培养 10 周期间测定植物生理参数。

 结果

SV 降低了土壤重金属的生物利用度，改善了植物生长和光合作用，并降低了所有器官中的重金属浓度。相比之下，LVL 增加了重金属生物利用度和根系生长，但抑制了芽的生长。LVL 降低了根系重金属浓度，但增加了芽中的重金属浓度。这两种类型的修正都增加了工厂去除的重金属总量。在去除的 Cd 和 Zn 中，只有不到 5% 被浸出去除，SV 有助于减少渗流。SV 通过减少污染物吸收来促进压力避免，而 LVL 通过加强内源性保护机制促进压力耐受性。

 结论

SV 和 LVL 都是 Z. fabago 对植物稳定和植物提取重金属的有益修正剂，但通过与矿物质营养、氧化应激和渗透调节相关的不同机制作用于植物。