Effects of the Application of Excessive Amounts of Sodium or Potassium on the Growth and Quality of Rapeseed (Brassica napus L.)

Abstract

To investigate whether the application of excessive amounts of cations (Na⁺ or K⁺) can promote plant growth and quality, hydroponically cultivated rapeseed plants were treated with high (100 mM), moderate (20 mM), or standard (6 mM) concentrations of NaCl or KCl. The treated plants were analyzed regarding their fresh weight, photosynthetic parameters, and abundance of selected phytochemicals with potential benefits for human health. Growth and photosynthesis were inhibited by the high cation concentration, while the effects of the moderate cation concentration were similar to those induced by the standard concentration. Additionally, the glucosinolate content increased following the application of 20 mM NaCl or KCl. Meanwhile, the chlorophyll and β-carotene contents increased significantly in response to 20 mM KCl, but not 20 mM NaCl.In summary, rapeseed quality improved, while growth was maintained, following the application of 20 mM NaCl or KCl,but KCl had a greater effect than NaCl.