蚯蚓粪对柑橘幼苗抗草甘膦胁迫的影响

草甘膦在柑橘园除草中得到大量使用，对农作物生长、果实品质、产量和质量造成影响。如何降低草甘膦对柑橘树的生物可利用性，从而降低其对农作物造成的药害、提高果实品质和食品安全将至关重要。本文在前期研究的基础上通过施用蚯蚓粪，表征蚯蚓粪作用下土壤中残留草甘膦对柑橘幼苗的生物有效性和生物毒性效应。结果显示，蚯蚓粪能够显著增强其生物有效性（BCF值显著增大）；显著降低草甘膦在土壤中的残留量到草甘膦单独处理组的55.15%，从而减少草甘膦在柑橘幼苗植株中的积累。同时，蚯蚓粪的施用能促进植物的茁壮生长，使抗氧化酶活力较对照组显著提高，从而具有更强的抗逆能力。在这两方面的共同作用下，蚯蚓粪显著减轻了土壤中残留草甘膦对柑橘幼苗的胁迫，使其株高、根长和相应的干重较草甘膦单独施用时增长了26.23%-140.11%，甚至成为对照组的1.03倍和1.13倍。此研究对兼顾化肥有机替代的草甘膦污染土壤的修复和高效利用具有重要意义。

Effect of Earthworm Casts on Resistance of Citrus Seedlings to Glyphosate Stress

The extensive use of glyphosate in weeding of citrus garden, owing to its excellent weed control efficacy, has caused damage on the plant growth, the fruit yield and quality. Thus, how to reduce the bioavailability of glyphosate to the citrus trees, thereby alleviating its phytotoxicity would be be of the utmost importance. In this paper, on the basis of our previous study, we characterized the bioavailability and phytotoxicity of soil glyphosate to citrus plants with and/or without earthworm casts. The results exhibited that, on the one hand, application of earthworm casts could significantly enhance the bioavailability of soil glyphosate (the increased BCF values); on the other hand, earthworm casts coud largely decrease the amount fo glyphosate residue in the soil by 55.15% in compare with the treatment with glyphosate alone, thus reducing rather than increasing the accumulative level of glyphosate in citrus seedlings. At the same time, earthworm casts can promote the plants thrive, with more active antioxidant enzymes, thus possess much stronger resistance to adversity. Consequently, involvement of earthworm casts notebly mitigated the glyphosate-induced stress on citrus seedlings, increasing their plant height, root length and dry weight of the corresponding parts by 26.23% to 140.11% when compared to the treatment with glyphosate alone, even up to 1.03 times and 1.13 times of the blank control. Our findings would be of great significance for the remediation and efficient utilization of glyphosate contaminated soil.