Aims

This study aims to investigate the impact of exopolysaccharides (EPS) from Rhizobium tropici on the growth of wheat (Triticum aestivum) seedlings under varying aluminum (Al) concentrations. We explored EPS mitigation of Al toxicity, a major growth-limiting factor in global acidic soils.

Methods

The effects of EPS on wheat were assessed by measuring shoot and root growth, photosynthesis, and lipid peroxidation under different Al concentrations. The study also examined Al uptake and transport within the plant as affected by EPS.

Results

Al exposure was found to substantially decrease shoot and root growth, impede photosynthesis, and cause intense lipid peroxidation in wheat. Application of EPS notably enhanced wheat growth, increasing shoot and root lengths by 86% and 244%, respectively, and dry biomasses of both shoots and roots by 100% and 104%, respectively, compared to the non-EPS treated group. EPS also limited Al absorption and transport in wheat, bolstering antioxidant defense against the oxidative stress. Subcellular analysis revealed that EPS promoted Al accumulation in cell walls and cytosol compartmentalization. Additionally, EPS appeared to regulate phosphorus (P) distribution within subcellular components, mitigating membrane lipid peroxidation and thereby enhancing plant’s Al resistance.

Conclusions

EPS effectively mitigates Al toxicity in wheat seedlings, suggesting its potential application for alleviating Al stress in plants. The study offers new perspectives for potential using EPS in agricultural practices, particularly in acidic soils. Future research should focus on field trials to validate these findings.

中文翻译：

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来自热带根瘤菌的胞外多糖减轻了小麦中的铝植物毒性

 目标

本研究旨在探讨热带根瘤菌胞外多糖 （EPS） 对不同铝 （Al） 浓度下小麦 （Triticum aestivum） 幼苗生长的影响。我们探索了 EPS 减轻 Al 毒性的方法，Al 毒性是全球酸性土壤中的主要生长限制因素。

 方法

通过测量不同 Al 浓度下的地上部和根系生长、光合作用和脂质过氧化来评估 EPS 对小麦的影响。该研究还检查了受 EPS 影响的植物内 Al 吸收和运输。

 结果

发现 Al 暴露会显着降低小麦的芽和根生长，阻碍光合作用，并导致强烈的脂质过氧化。与未 EPS 处理的组相比，EPS 的应用显着促进了小麦生长，芽和根长分别增加了 86% 和 244%，芽和根的干燥生物量分别增加了 100% 和 104%。EPS 还限制了小麦对铝的吸收和运输，增强了对氧化应激的抗氧化防御。亚细胞分析显示，EPS 促进 Al 在细胞壁中的积累和胞质溶胶区室化。此外，EPS 似乎可调节亚细胞成分内的磷 （P） 分布，减轻膜脂质过氧化，从而增强植物的 Al 抗性。

 结论

EPS 可有效减轻小麦幼苗中 Al 的毒性，表明其在缓解植物 Al 胁迫方面的潜在应用。该研究为在农业实践中使用 EPS 的可能性提供了新的视角，尤其是在酸性土壤中。未来的研究应侧重于田间试验以验证这些发现。