林下菌肥对五指毛桃根系生长的差异代谢响应OA

[Purpose]This study compared the effects of microbial fertilization on root phenotypes and root metabolites of Ficus hir-ta cultivated under different stands,aiming to provide a reference for improving the quality of F.hirta and enhancing understory planting efficiency.[Method]F.hirta was planted under Camellia oleifera and Cunninghamia lanceolata forests.Root morphology measurement and non-targeted metabolomics were employed to systematically investigate the effects of understory microbial fertiliza-tion on the root growth and metabolic regulation mechanisms of F.hirta,through root phenotype analysis,differential metabolite screening,and KEGG pathway enrichment analysis.[Result](1)After microbial fertilization,the root length and root area of Fi-cus hirta under the Camellia oleifera forest reached 45.8 cm and 110.5 cm2,respectively,which were 46.3%and 14.0%higher than those(31.3 cm and 96.9 cm2,respectively)under the Cunninghamia lanceolata forest.(2)Metabolomics analysis identified a total of 7 983 metabolites.Compared with the control without microbial fertilization,the F.hirta with microbial fertilization under Cun-ninghamia lanceolata and Camellia oleifera forests showed 4 454 and 3 188 differential metabolites,respectively.Among them,the number of terpenoids and fatty acids was generally downregulated.Under the Camellia oleifera forest,the number of upregulated al-kaloids in F.hirtaroots was higher,whereas under the Cunninghamia lanceolata forest,the number of downregulated alkaloids was higher.A total of 3 436 differential metabolites were identified in F.hirta roots under the Camellia oleifera forest in comparison with that under the Cunninghamia lanceolata forest,with significantly more upregulated terpenoids than downregulated ones.Venn analy-sis showed that 2 372 common differential metabolites were shared between the two forest types after microbial fertilization,mainly including terpenoids,fatty acids,shikimic acid,and phenylpropionic acids,more of which were downregulated than upregulated.KEGG enrichment analysis further revealed that these differential metabolites were mainly enriched in significant pathways such as alanine,aspartate and glutamate metabolism,flavonoid and flavonol biosynthesis,isoquinoline alkaloid biosynthesis,galactose me-tabolism,the pentose phosphate pathway,and starch and sucrose metabolism.(3)The average fresh weight per plant of F.hirta treated with microbial fertilizer under Camellia oleifera and Cunninghamia lanceolata forests was 67.103 g and 49.427 g higher than that of their respective non-fertilized controls.[Conclusion]Microbial fertilizer promotes the root morphological development of F.hirta by reconstructing the root carbon allocation pattern,regulating energy metabolism and cell wall synthesis pathways.Moreover,the plant growth-promoting effect is more pronounced under the Camellia oleifera forest than under the Cunninghamia lanceolata forest.