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杉木林下多花黄精根际土壤微生物群落结构与功能差异
Differences in Soil Microbial Community Structure and Function in the Rhizosphere of Polygonatum cyrtonema Hua under Cunninghamia lanceolata Plantations
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摘要: 以杉木林下不同生长时期的多花黄精播种苗和根茎苗为研究对象,采用采用宏基因组测序结合土壤理化性质分析,比较根际与非根际土壤微生物群落在结构、功能上的差异,并探讨其与环境因子的关系。结果表明:杉木林下多花黄精土壤微生物群落受生长时期、根际效应和育苗方式共同影响,群落结构存在明显分化。Shannon指数为4.811~5.583,差异不显著;非根际播种苗成熟期丰富度最高(ACE
1868.69 ,Chao11917.66 )。群落组成上,播种苗中期显著富集假单胞菌属(Pseudomonas)、类芽孢杆菌属(Paenibacillus)和硝化螺菌属(Nitrospira);根茎苗中后期则富集链霉菌属(Streptomyces)、节杆菌属(Arthrobacter)和中村菌属(Nakamurella)等耐逆类群。功能上,非根际播种苗成熟期富集碳水化合物代谢、氨基酸代谢和能量代谢等功能(LDA=4.17~5.06),根际播种苗中期富集膜转运和氨基酸代谢(LDA=4.18~4.86),非根际根茎苗成熟期富集蛋白折叠、分选与降解以及辅因子和维生素代谢功能(LDA=4.42~4.88)。NH4+-N是影响功能模块变化的主要环境因子,解释率18.6%,且差异显著。杉木林下多花黄精根际微生物群落在不同育苗方式和生长阶段表现出显著的结构分化与功能重塑,播种苗中后期以养分转化和氮转化功能为主,而根茎苗中后期则体现胁迫适应与生态稳态维持能力。Abstract: This study investigated seedlings and rhizome-propagated seedlings of Polygonatum cyrtonema at different growth stages under a Chinese fir forest, employing metagenomic sequencing combined with soil physicochemical property analysis to compare structural and functional differences in microbial communities between rhizosphere and non-rhizosphere soils, and to explore their relationships with environmental factors. The results showed that rhizosphere and non-rhizosphere microbial communities of P. cyrtonema were jointly influenced by growth stage, rhizosphere effect, and propagation mode, resulting in significant community differentiation(R2=0.487, P=0.001). The Shannon index ranged from 4.811 to 5.583, with no significant differences among treatments; the highest richness was observed in the non-rhizosphere soils of mature seed-propagated plants(ACE=1868.69 , Chao1=1917.66 ). In terms of community composition, at the mid-growth stage, seedlings propagated from seeds showed significant enrichment of Pseudomonas, Paenibacillus, and Nitrospira. In contrast, rhizome-propagated seedlings were enriched in stress-tolerant taxa, including Streptomyces, Arthrobacter, and Nakamurella, during the middle and late growth stages.. Functionally, the non-rhizosphere soils of mature seed-propagated plants were enriched in carbohydrate metabolism, amino acid metabolism, and energy metabolism(LDA=4.17–5.06);the rhizosphere of mid-stage seed-propagated plants was enriched in membrane transport and amino acid metabolism(LDA=4.18–4.86); and the non-rhizosphere soils of mature tuber-propagated plants were enriched in protein folding/sorting/degradation and cofactors and vitamin metabolism (LDA=4.42–4.88). RDA analysis showed that ammonium nitrogen (NH4+-N) was the primary environmental factor influencing changes in microbial functional modules, explaining 18.6% of the variation, with a significant effect. In conclusion, the rhizosphere microbial communities of P. cyrtonema under Cunninghamia plantations showed pronounced structural differentiation and functional remodeling across propagation modes and growth stages. During the middle and late growth stages, seed-propagated seedlings tended to adopt a nutrient- and nitrogen-transformation-oriented strategy, whereas rhizome-propagated seedlings exhibited stronger stress-adaptation and homeostasis-maintenance characteristics. NH4+-N may be a key driving factor underlying these shifts. The study provides a theoretical basis for rhizosphere microecological regulation,cultivation optimization,and disease prevention and control of P. cyrtonema under Chinese fir plantations.
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