| Selenium is an essential element for human body,which plays a better role in enhancing immunity and preventing diseases.At present,the way to supplement selenium in human body utilization rate is low,and there are side effects.Microbial nano-selenium is a hot spot of new selenium supplement with high safety,strong biological activity and high efficiency of transformation and absorption.Therefore,it is important to study the effect of nano-selenium as a kind of nutrient fertilizer by microbial reduction on plant nutrient elements.In this study,a strain with reducing disodium selenite was selected from se-enriched soil,and the culture conditions of the strain were explored.The compound use of Nano Se and foliar fertilizer was obtained by reducing disodium selenite,to observe the effect of nano-selenium on the nutritional substance of tomato,the main results are as follows:A strain resistant to 100 mmol·L-1sodium selenite was isolated from soil samples collected from fields and forests in the selenium-rich area of Hailun,Heilongjiang,China.It was identified as Serratia Marcescens after gene sequencing.The growth and disodium selenite tolerance of Serratia marcescens T24 were studied.The results showed that the optimum growth pH of Serratia Marcescens T24 was 6.0 and the optimum temperature was 30℃.The addition of disodium selenite prolonged the growth cycle of the bacteria,and with the increase of disodium selenite concentration,the content of the bacteria significantly decreased and the colony became smaller.The results showed that disodium selenite had certain toxic and side effects on the growth of the bacteria.The structure of the synthesized nano-selenium is stable and is not easy to be transformed.The effects of nano-selenium on the quality of tomato were studied by spraying different concentrations of nano-selenium foliar fertilizer at regular intervals after stabilization of tomato seedlings.The results showed that the ripening process of tomatoes treated with nano-selenium fertilizer was advanced,the yield of 3(10μmmol·L-1nano-Se)in treatment group was more significant than that of Control Group.The selenium content of 4(20μmmol·L-1nano-Se)in treatment group was 1.104 mg·kg-1,and the effect of Vc content in Treatment Group 4 was 18.50 mg·100mg-1.The best effect of Soluble Sugar Treatment Group 3 was 9.33 mg·g-1.Compared with other treatments,the results showed that treatment 3,namely the concentration of nano-selenium was 10μmmol·L-1,had the best effect.Herefore,it is of great significance to prove that nano-selenium synthesized by microbial transformation can be applied to plant se-enrichment and improve the production of edible plant se-enrichment products. |
