Foliar magnesium application enhanced growth and root exudation from wheat in acid soil
Soil acidity is one of the most important soil constraints for wheat growth, and magnesium (Mg) can play a critical role in mitigating the adverse effects of soil acidity on plants. There is, however, the limited information available about the influence of Mg nutrition, especially foliar application, on wheat growth in acidic soil. In a series of glasshouse experiments, the growth of two wheat genotypes differing in aluminium (Al) resistance was investigated with or without foliar Mg application. Applying Mg to foliage at the optimum rate (200 mg Mg/L) was associated with a significant increase in shoot and root dry biomass accumulation, root length and leaf chlorophyll content by 50%, 38%, and 10%, respectively compared to the treatment with no foliar Mg applied. This increase was higher in the Al-resistant wheat genotype compared with Al-sensitive one. Foliar Mg application at an optimum rate resulted in a significant increase in root exudation (malate and citrate), which contributes to enhancing wheat growth in acidic soil. The root exudation was higher in the Al-resistant wheat genotype compared to Al-sensitive one. It appears that growing Al-resistant genotype coupled with foliar Mg application at the optimum rate might be helpful to minimize the adverse effect of soil acidity on wheat growth.