Jezek Mareike, Geilfus Christoph-Martin, Bayer Anne, Mühling Karl-Hermann
Faculty of Agricultural and Nutritional Sciences, Institute of Plant Nutrition and Soil Science, Kiel University Kiel, Germany.
Front Plant Sci. 2015 Jan 9;5:781. doi: 10.3389/fpls.2014.00781. eCollection 2014.
The major plant nutrient magnesium (Mg) is involved in numerous physiological processes and its deficiency can severely reduce the yield and quality of crops. Since Mg availability in soil and uptake into the plant is often limited by unfavorable soil or climatic conditions, application of Mg onto leaves, the site with highest physiological Mg demand, might be a reasonable alternative fertilization strategy. This study aimed to investigate, if MgSO4 leaf-application in practically relevant amounts can efficiently alleviate the effects of Mg starvation in maize, namely reduced photosynthesis capacity, disturbed ion homeostasis and growth depression. Results clearly demonstrated that Mg deficiency could be mitigated by MgSO4 leaf-application as efficiently as by resupply of MgSO4 via the roots in vegetative maize plants. Significant increases in SPAD values and net rate of CO2-assimilation as well as enhanced shoot biomass have been achieved. Ion analysis furthermore revealed an improvement of the nutrient status of Mg-deficient plants with regard to [Mg], [K], and [Mn] in distinct organs, thereby reducing the risk of Mn-toxicity at the rootside, which often occurs together with Mg deficiency on acid soils. In conclusion, foliar fertilization with Mg proved to be an efficient strategy to adequately supply maize plants with Mg and might hence be of practical relevance to correct nutrient deficiencies during the growing season.
主要植物养分镁（Mg）参与众多生理过程，其缺乏会严重降低作物产量和品质。由于土壤中镁的有效性以及植物对镁的吸收常常受到不利土壤或气候条件的限制，向叶片（生理需镁量最高的部位）施用镁可能是一种合理的替代施肥策略。本研究旨在调查，以实际相关用量叶面喷施硫酸镁是否能有效缓解玉米缺镁的影响，即光合能力降低、离子稳态紊乱和生长受抑。结果清楚地表明，在营养生长期的玉米植株中，叶面喷施硫酸镁缓解缺镁的效果与通过根系供应硫酸镁一样有效。实现了叶绿素含量（SPAD值）和二氧化碳同化净速率的显著增加以及地上部生物量的提高。离子分析还显示，缺镁植株不同器官中镁、钾和锰的养分状况得到改善，从而降低了根际锰中毒的风险，锰中毒在酸性土壤上常与缺镁同时发生。总之，叶面喷施镁被证明是向玉米植株充分供应镁的有效策略，因此可能对在生长季节纠正养分缺乏具有实际意义。
