Influences of earthworm activity and mucus on Cd phytoremediation based on harvesting different leaf types of tall fescue (Festuca arundinacea)

TL;DR

This study explores how earthworms and their mucus help plants clean up cadmium from soil, with a focus on harvesting specific leaves for better efficiency.

Contribution

The study introduces selective leaf harvesting as a sustainable and cost-effective phytoremediation strategy enhanced by earthworm activity.

Findings

Earthworm activity increased leaf dry weight by 13.5% and boosted Cd accumulation in senescent leaves by over 85%.

Earthworm mucus had a less pronounced effect on Cd redistribution compared to live earthworms.

Selective harvesting of senescent leaves supported by earthworm activity improves phytoremediation efficiency.

Abstract

To explore cost-effective and efficient phytoremediation strategies, this study investigated the distinct roles of earthworm activity and mucus in enhancing Cd phytoextraction from soils contaminated by Festuca arundinacea, focusing on the comparative advantages of selective leaf harvesting versus traditional whole-plant harvesting methods. Our study employed a horticultural trial to explore how earthworm activity and mucus affect Festuca arundinacea’ s Cd phytoremediation in soils using control, earthworm, and mucus treatments to examine their respective effects on plant growth and Cd distribution. Earthworm activity increased the dry weight of leaves by 13.5% and significantly increased the dry weights of declining and senescent leaves, surpassing that of the control by more than 40%. Earthworm mucus had a similar, albeit less pronounced, effect on plant growth than earthworm activity. This study not only validated the significant role of earthworm activity in enhancing Cd phytoextraction by Festuca arundinacea, with earthworm activity leading to over 85% of Cd being allocated to senescent tissues that comprise only approximately 20% of the plant biomass, but also highlighted a sustainable and cost-effective approach to phytoremediation by emphasizing selective leaf harvesting supported by earthworm activity. By demonstrating that earthworm mucus alone can redistribute Cd with less efficiency compared to live earthworms, our findings offer practical insights into optimizing phytoremediation strategies and underscore the need for further research into the synergistic effects of biological agents in soil remediation processes.

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