Chen Jihui, Li Yanpeng, Wen Shilin, Rosanoff Andrea, Yang Gaowen, Sun Xiao
College of Agro-Grassland Science, Nanjing Agricultural University , Nanjing 210095, People's Republic of China.
Hengyang Red Soil Experimental Station, Chinese Academy of Agricultural Sciences , Hengyang 421001, People's Republic of China.
J Agric Food Chem. 2017 Apr 26;65(16):3253-3258. doi: 10.1021/acs.jafc.6b05764. Epub 2017 Apr 12.
Magnesium (Mg) plays important roles in photosynthesis and protein synthesis; however, latent Mg deficiencies are common phenomena that can influence food quality. Nevertheless, the effects of Mg fertilizer additions on plant carbon (C):nitrogen (N):phosphorus (P) stoichiometry, an important index of food quality, are unclear and the underlying mechanisms unexplored. We conducted a greenhouse experiment using low-Mg in situ soil without and with a gradient of Mg additions to investigate the effect of Mg fertilizer on growth and stoichiometry of maize and soybean and also measure these plants' main symbiotic microorganisms: arbuscular mycorrhizal fungi (AMF) and rhizobium, respectively. Our results showed that Mg addition significantly improved both plant species' growth and also increased N and P concentrations in soybean and maize, respectively, resulting in low C:N ratio and high N:P ratio in soybean and low C:P and N:P ratios in maize. These results presumably stemmed from the increase of nutrients supplied by activation-enhanced plant symbiotic microorganisms, an explanation supported by statistically significant positive correlations between plant stoichiometry and plants' symbiotic microorganisms' increased growth with Mg addition. We conclude that Mg supply can improve plant growth and alter plant stoichiometry via enhanced activity of plant symbiotic microorganisms. Possible mechanisms underlying this positive plant-soil feedback include an enhanced photosynthetic product flow to roots caused by adequate Mg supply.
镁（Mg）在光合作用和蛋白质合成中发挥着重要作用；然而，潜在的镁缺乏是常见现象，会影响食物品质。尽管如此，添加镁肥对植物碳（C）：氮（N）：磷（P）化学计量比（食物品质的一个重要指标）的影响尚不清楚，其潜在机制也未被探索。我们进行了一项温室实验，使用低镁原位土壤，设置不添加镁和添加不同梯度镁的处理，以研究镁肥对玉米和大豆生长及化学计量比的影响，并分别测定这些植物的主要共生微生物：丛枝菌根真菌（AMF）和根瘤菌。我们的结果表明，添加镁显著促进了两种植物的生长，还分别提高了大豆和玉米中的氮和磷浓度，导致大豆中碳氮比降低、氮磷比升高，玉米中碳磷比和氮磷比降低。这些结果可能源于植物共生微生物活化增强所提供养分的增加，植物化学计量比与添加镁后植物共生微生物生长增加之间具有统计学显著正相关，这一结果支持了上述解释。我们得出结论，镁供应可以通过增强植物共生微生物的活性来促进植物生长并改变植物化学计量比。这种积极的植物 - 土壤反馈的潜在机制可能包括充足的镁供应导致光合产物向根系的流动增强。
