Background and aims

Enhancing selenium (Se) accumulation in crops is an important way to overcome human Se deficiency. However, increasing the Se content in the soil can produce toxic effects in crops. This study aimed to clarify the role of exogenous foliar jasmonic acid (JA) on alleviating Se toxicity of pak choi exposed to high levels of Se-toxicity in the soil.

Methods

Pak choi were exposed to high levels of soil Se stress and evaluate the physiological response, variation of Se accumulation and metabolites in the rhizosphere of plants treated with JA compared to those untreated under soil Se stress.

Results

Se stress severely inhibited pak choi growth and biomass accumulation by reducing their photosynthetic capacity of photosystem II and inducing a heavy lipid peroxidation. When plants were sprayed with JA, 23.7% lower levels of lipid peroxidation was found, but higher levels of Fv/Fm (1.6%), Fvꞌ/Fmꞌ (11.8%), qP (40.0%), ETR (56.4%), catalase activity (82.8%), shoot biomass (38.1%) and Se content in the shoots (17.8%). Fifty-three metabolic compounds were altered in response to JA application compared to the Se group. Of those, JA application induced increased secondary metabolites of the rhizosphere, including organoheterocyclic compounds, lipids and lipid-like molecules, organic acids and derivatives, and benzenoids, which may be crucial for defense against Se stress and Se accumulation.

Conclusions

Foliar spraying with JA is an effective measure to alleviate the adverse effects of Se stress and enhance Se accumulation for optimizing crop Se biofortification in high Se soil.

中文翻译：

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施用外源茉莉酸增强了白菜 （Brassica chinensis L.） 对土壤中高水平硒毒性的抵抗力

 背景和目标

增强作物中硒 （Se） 的积累是克服人类 Se 缺乏症的重要方法。然而，增加土壤中的 Se 含量会对作物产生毒性作用。本研究旨在阐明外源叶面茉莉酸 （JA） 对减轻土壤中高水平硒毒性的白菜硒毒性的作用。

 方法

白菜暴露于高水平的土壤硒胁迫下，并评估了与未在土壤硒胁迫下处理的植物相比，JA处理的植物根际硒积累和代谢物的生理响应、硒积累和代谢物的变化。

 结果

硒胁迫通过降低白菜的光合能力 II 并诱导严重的脂质过氧化，严重抑制白菜的生长和生物量积累。当植物喷施 JA 时，脂质过氧化水平降低了 23.7%，但 Fv/Fm （1.6%） 、Fvꞌ/Fmꞌ （11.8%）、qP （40.0%）、ETR （56.4%）、过氧化氢酶活性 （82.8%）、地上部生物量 （38.1%） 和地上部的 Se 含量 （17.8%） 水平较高。与 Se 组相比，JA 应用改变了 53 种代谢化合物。其中，JA 应用诱导了根际次生代谢物的增加，包括有机杂环化合物、脂质和脂质样分子、有机酸和衍生物以及苯类化合物，这可能对防御 Se 应激和 Se 积累至关重要。

 结论

叶面喷施 JA 是减轻硒胁迫不利影响和增强硒积累的有效措施，有助于优化高硒土壤中作物硒的生物强化。