Studies On The Improvement Of Saline-alkali Soil And Rice Growth Promotion By Wild Rice Rhizosphere Bacteria

Saline-alkali soil is an important land resource.With the increasing demand for food and the declining of cultivated land resources,comprehensive management,development and utilization of saline-alkali land resources have become urgent issues for environmental governance and future agricultural development.In this paper,salt tolerant bacteria were screened from the in-situ soil of Guangdong wild rice and Jiangxi wild rice,as well as from the rhizosphere soil samples of Northeast China black soil with long-term controlled cultivation,and then were inoculated to the root of rice and alkali soil for testing their improving effects on rice growth and alkali soil.In addition,the effects of wild rice cultivars and soil types on the tendency and diversity of salt-tolerant bacteria were analyzed at the same saline-alkali level.This study will provide certain references value and research direction for the utilization of wild rice resources in Northeast China,the effects of microorganisms on saline-alkali tolerance of rice and alkali land improvements.The findings are as follows:Firstly,40 strains of saline-alkali-resistant bacteria that can grow normally in a medium with a Na Cl concentration of 60 g/L and p H 8 were screened from the rhizosphere soil of wild rice.14 strains of bacteria were screened from soil sample 1,8 strains from soil sample 2,15strains from soil sample 3,and 3 strains from soil sample 4.Then,the functions of catalase production,starch hydrolase production,cellulose degradation,insoluble organic phosphorus degradation,insoluble organic phosphorus degradation and chitinase production were identified in the strains.Among them,2 strains with good salt and alkali tolerance and function were named by GDW1-8 and DXB3-4.Secondly,at the salt alkali level of 60 g/L Na Cl and p H 8,the diversity of functional saline-alkali-resistant bacteria in situ soil of wild rice was higher than that in black soil;the diversity of saline-alkali-resistant bacteria in situ soil of Jiangxi wild rice was lower than that in situ soil of Guangdong wild rice.In the black soil of Northeast China,the functional saline-alkali-resistant bacteria are more inclined to the root system of Jiangxi wild rice.Thirdly,strain GDW1-8 was identified as Bacillus Megaterium,GDW1-8 can dissolve insoluble Ca₃?PO₄?₂,and the amount of phosphorus is 547.48 mg/L.The mechanism of dissolving phosphorus is to transform insoluble phosphate into soluble phosphate by releasing organic acid and aohe Ca²⁺.Furthermore,GDW1-8 had a high growth promotion effect on rice seedlings in saline-alkali environment.At last,strain DXB3-4 was identified as Serratia Proteamaculans,DXB3-4 has the function of decomposing chitin/chitosan and insoluble Ca₃?PO₄?₂.Due to chitin is the main component of fungal cell wall,DXB3-4 exerts inhibitory effects on the pathogenic fungi of rice blast,black spot,black rot,grey mould,stem rot and sickle disease.In addition,DXB3-4 has displaying significant improvement effect on saline-alkali soil.