Increasing root and leaf growth and yield in Mg‐deficient faba beans (Vicia faba) by MgSO4 foliar fertilization

Abstract Magnesium (Mg) deficiency reduces yield and quality of crops as Mg is involved in carbohydrate and protein anabolism. Foliar application of MgSO 4 represents a means of ameliorating the nutritional status of crops growing under conditions of deficiency. Foliar Mg application has been demonstrated to increase the chlorophyll concentration and vegetative yield of plants. However, in crop plants used for seed production, the limited number of available studies provides only conflicting results in terms of the efficiency of Mg leaf application on yield and quality. We have examined the effect of increasing Mg foliar application rates on differentially developed leaves and leaf stages with regards to Mg concentration, chlorophyll concentration and biomass formation. Our data reveal that in order to obtain significant effects MgSO 4 concentrations in the spraying solution should be higher than 50 mM, as lower concentrations did not lead to significant changes in the vegetative or generative material. Positive effects of the foliar application on chlorophyll concentration and leaf area were only measured in leaves treated with 200 mM foliar MgSO 4 . The application of Mg did not affect the parameters chlorophyll, ion concentration and leaf area in the newly developing leaves, but it had an important influence with regard to yield traits, especially on the formation of pods. The quality of the seeds with regard to the protein concentration was reduced in response to the magnesium deficiency treatment, but the application of foliar magnesium prevented a significant loss of protein.