Changes in growth and magnesium concentration of wheat and coffee plants grown under various magnesium and water stress treatments

Magnesium (Mg) deficiency has become a widespread problem in acidic and sandy agricultural soils, and it is often associated with marginal soil conditions such as drought stress. Impairment in growth and development of sink organs is a common consequence of Mg deficiency. However, mode of action of these impairments is not well understood. This study was conducted to investigate the changes in growth and Mg concentrations of wheat (Triticum aestivum cv. Adana99) and coffee (Coffea arabica cv. Murta) plants that were grown under controlled greenhouse conditions with different Mg supplies and water stress treatments. Growing wheat plants under varied Mg supply showed that foliar application of Mg to low Mg plants improved grain yield by increasing seed weight without affecting seed number per spike. Starch content and Mg concentration of the seeds were increased under foliar application of Mg to Mgdeficient plants. Growth and grain yield of low Mg plants were further reduced when grown under drought stress. An adequate Mg supply was needed to maintain better yield and higher grain Mg concentrations under drought. In experiment with coffee plants, Mg transport within plants was studied after the immersion of the fully expanded young leaves in a solution containing stable Mg isotope (26Mg). Transport of 26Mg from treated leaves was greater in plants with adequate Mg supply than the plants with low Mg. In addition, under low Mg supply 26Mg concentration of roots was found higher when compared to Mg-adequate roots. The results obtained highlighted the importance of Mg in growth and seed formation and accumulation of Mg in sink organs such as seed and young leaves after foliar treatment of Mg.