EFFECTS OF DIFFERENT SUBSTRATE ADDITIONS ON GROWTH STATUS OF SUBMERGED PLANTS AND RHIZOSPHERE MICROORGANISMS IN SEDIMENTS

Sediment is an important factor affecting the growth of aquatic plants.The effects of sediment substrate application on aquatic plants and rhizosphere microorganisms are poorly understood.This study examined the effects of four substrates (maifanite, vermiculite, ceramsite, and volcanic rock gravels) on the growth and rhizosphere microorganisms of Vallisneria natans (Lour.)Hara using Illumina highthroughput sequencing technology.The results showed that the root activity of V. natans in the four treatment groups was higher than that in control group (CK) during the whole experimental period.Catalase activity in leaves in the same treatment groups, except the maifanite group, was significantly different during different periods (P < 0.05).All four treatment groups exhibited faster reduction in malondialdehyde content in leaves than the CK group, indicating that substrate addition could rapidly enhance plant stress adaptation.Redundancy analysis showed that root vitality positively correlated with biomass, plant height, and root length, and that different substrates had different effects on the growth of V. natans.Relative abundance of Desulfobacterota and Nitrospirota was higher in the treatment groups than in the CK group.Our results indicated that substrate addition, especially maifanite, into lake sediments could promote the growth of submerged plants and improve the rhizosphere microbial community structure.