Abstract
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 JA on alleviating Se toxicity of pak choi exposed to high levels of Se-Toxicity in the Soil.
Methods
Here, subject a model crop, pak choi (Brassica chinensis L.) to high levels of soil Se stress and evaluate the physiological response, variation of Se accumulation and root exudates of plants treated with JA compared to those untreated under soil Se stress.
Results
We found that Se stress severely inhibits pak choi growth and biomass accumulation by reducing their photosynthetic capacity of photosystem II and inducing a heavy lipid peroxidation. When we sprayed plants with JA, we found lower levels of lipid peroxidation, but enhanced photochemical reactions of PSII, catalase activity, and shoot biomass, as well as higher Se content in the shoots. We found 53 metabolic compounds were altered by JA application compared to Se group (21 upgraded and 32 downgraded). Of those, JA application induced increased in secondary metabolites of root secretions, including organoheterocyclic compounds, lipids and lipid-like molecules, organic acids and derivatives, and benzenoids, which may be crucial for defense against Se stress defense and Se accumulation.
Conclusions
This study provides us novel insights to understand the potential for JA to enhance Se tolerance and accumulation in pak choi, as well as its underlying mechanisms.