不同磷肥背景下糖原对红壤细菌群落结构的影响

Influence of glycogen on bacterial community structure of the red soil under different scenarios of phosphate fertilizers

前期研究表明糖原能提高缺磷土壤中微生物的代谢活性,但缺磷土壤中不同磷肥条件下微生物群落对糖原的响应机制目前尚不清楚.以红壤为研究对象,采用温室盆栽方式研究在不施磷肥、施用磷酸二氢钾、施用钙镁磷肥背景下添加糖原对生菜(Lactuca sativa L.)地上生物量、土壤速效磷及土壤细菌群落的影响.结果表明,无磷肥背景下,添加糖原使生菜地上生物量增加了140%、土壤有效磷含量增加了20%,并显著提高了土壤细菌群落的多样性;在施用磷肥条件下,糖原均降低地上生物量以及细菌群落多样性,且在钙镁磷肥背景下差异达到显著.在细菌群落组成及预测功能上,无磷肥时加入糖原显著增加土壤中变形菌门中Rhodanobacter和Bradyrhizobium的比例,提高了能量代谢及氨基酸代谢基因的相对丰度;在钙镁磷肥背景下,添加糖原显著降低了放线菌门中Conexibacte和Acidothermus比例,以及氮代谢基因的相对丰度;在磷酸二氢钾背景下,糖原对细菌群落组成和多样性的影响不显著.本研究表明不施磷肥时糖原对植物生长及细菌群落多样性具有促进作用,可提升土壤质量;在磷肥特别是枸溶性磷肥存在时,糖原会对植物生长及微生物群落多样性产生负面影响.

Previous studies have shown that glycogen can increase microbial metabolic activity in phosphorusdeficient soils.However,the response of soil microbial communities to the addition of glycogen under different phosphate fertilization levels in phosphorus-deficient soil is still unclear.In this study,a pot experiment was conducted to investigate the effect of glycogen addition on the growth of lettuce(Lactuca sativa L.),soil available phosphorus content,and bacterial community in red soil under different phosphate fertilizer scenarios,i.e.,no phosphate fertilizer treatment,monopotassium phosphate(KH_(2)PO_(4))treatment and calcium magnesium phosphate fertilizer treatment.Our results showed that glycogen addition markedly increased the aboveground biomass of lettuce by 140%and phosphorus content available in the by 20%under the no phosphate fertilizer scenario.However,these parameters decreased under the phosphate fertilizer treatments,with a substantial effect observed under the scenario of calcium magnesium phosphate fertilization.In the soil bacterial community,glycogen addition increased the relative abundance of Rhodanobacter and Bradyrhizobium affiliated with Proteobacteria as well as the energy metabolism and amino acid metabolism genes in the no-phosphate fertilizer treatment.In the calcium magnesium phosphate fertilizer treatment,glycogen decreased the relative abundance of Conexibacte and Acidothermus,which belong to the family of Actinobacteria,and nitrogen metabolism genes.In contrast,no substantial differences in bacterial diversity were induced by glycogen in the KH_(2)PO_(4)nhi condition.Collectively,without phosphate fertilizer input,glycogen positively influenced the plant growth and diversity of the soil bacterial community,thus improving soil quality.Whereas,under the conditions of phosphate fertilizers,especially under the calcium magnesium phosphate fertilizer treatment,glycogen addition negatively influenced the plant growth and bacterial community diversity.