Study On The Mechanism Of Promoting Growth Of Peanut By Spraying Sorbitol Chelated Calciu

The nutrients in inorganic fertilizers are easily lost by soil fixation,adsorption and leaching,resulting in low fertilizer utilization rate,which accelerates soil acidification,compaction and eutrophication of water bodies,and causes waste of resources and energy.As an environment-friendly fertilizer,sugar alcohol chelated fertilizers have carried out a parcel of investigate on economic crops,and its application effect is by and large way better than that of inorganic fertilizers.However,the current research on sugar alcohol chelate fertilizers is less involved in food crops with a wide range of planting areas.In addition,the sugar alcohol chelated fertilizers applied in previous studies did not indicate the chelation rate,and usually existed in the form of mixtures,and even some were simply blended with sugar alcohols and inorganic fertilizers without chelation reaction.At the same time,our previous research found that the effects of different production processes of sugar alcohol chelated fertilizers are significantly different.A large number of studies have shown that sugar alcohol mixtures without chelation reaction also have better application effects in promoting crop growth,so it is difficult to determine whether sugar alcohol chelates play a more critical part in advancing crop development and improvement,which leads to the mechanism of the growth-promoting action of sugar alcohol chelates is unclear.In order to solve the above problems,this study first prepared a sorbitol chelated calcium with a chelation rate close to 100% by hydrothermal synthesis,and set up five groups of treatments according to its main synthetic components,which composed of(1)pure water(CK);(2)sorbitol(T1);(3)calcium nitrate(T2);(4)mixture of sorbitol and calcium nitrate(T3);(5)sorbitol chelated calcium(T4).Through Fourier transform infrared spectroscopy,elemental analysis,transmission electron microscopy and other technical means,the effects of spraying sorbitol chelated calcium on carbon and nitrogen metabolism,calcium absorption and subcellular distribution in peanut leaves were investigated under field test conditions.Combined with the changes in the phyllosphere microbial community structure,the mechanism of the growth-promoting effect of spraying sorbitol chelated calcium was analyzed to promote its application in food crops,and to quicken its advancement in agriculture in our nation.The main results are as follows:1、Foliar fertilization could improve the yield and quality of peanuts by promoting the growth of peanuts and increasing the number of fruits per plant,but the 100-pods weight and 100-kernels weight was reduced.Compared with other treatments,spraying sorbitol chelated calcium could significantly promote the development of reproductive and vegetative organs,thereby increasing the dry matter content of the plant.Compared with CK treatment,the average yield of T1,T2,T3 and T4 treatments increased by 3.16%,6.05%,8.48%,and 14.54%,respectively.The results of correlation analysis showed that the increase in yield was mainly due to the significant increase in the number of peanuts per plant.In terms of peanut kernel quality,foliar fertilization had little effect on the crude fat content of the seed kernels,but significantly increased the crude protein content,of which sorbitol chelated calcium played a prominent role.A principal component comprehensive assessment of peanut yield,quality,and growth parameters was performed,and the results showed that foliar manure applied on the basis of the application of basal manure was beneficial for economic benefit improvement of peanut,and the rank order of the composite score was T4,T3,T2,T1 and CK treatment.2、The carbon and nitrogen metabolism processes of peanut leaves were closely related and promoted each other.Foliar fertilization improved the carbon and nitrogen metabolism of peanut leaves,but the effects of different spraying treatments were different.Compared with other treatments,spraying sorbitol chelated calcium significantly increased the content of total carbon and total nitrogen in peanut leaves at each growth stage,and increased the content of metabolites such as soluble sugar,soluble protein and free amino acids.Foliar fertilization on nitrogen metabolism was more prominent than that of carbon metabolism,especially sorbitol chelated calcium treatment.Meanwhile,the correlation analysis results showed that the stronger the carbon and nitrogen metabolism,the higher the economic benefit,which could effectively promote the growth of peanuts and increase yield and high quality.The results of Fourier transform infrared spectroscopy advance demonstrated that the addition of sorbitol chelated calcium on the basis of conventional fertilization was beneficial to improve the carbon and nitrogen metabolism of leaves,and promoted the accumulation of carbohydrates and esters,proteins and nucleic acids in leaves,which could lay a physiological foundation for peanut dry matter accumulation,yield and kernel quality improvement.3、Foliar fertilization could promote the absorption of calcium by peanut plants and change the subcellular distribution of calcium in leaves.Since the wetting effect of sorbitol could reduce the contact angle between fertilizer spray and peanut leaves,foliar fertilization could significantly increase the calcium content of peanut plants.Compared with the conventional fertilization treatment,the leaf calcium content of sorbitol chelated calcium treatment was significantly increased by 19.32% and13.12%,and the calcium content of kernel was increased by 6.49% and 10.82%,respectively.Compared with the basal nutrient content before fertilization,the sorbitol chelated calcium treatment could effectively maintain the soil available calcium content.Foliar fertilization increased the calcium content of each fraction,but the proportion of cell wall fractions decreased compared with CK treatment,especially the sorbitol chelated calcium treatment.The results of transmission electron microscope showed that the distribution of calcium in cell wall treated with sorbitol chelated calcium was more continuous and uniform.The results of correlation examination appeared that foliar fertilization could significantly affect the yield,quality and growth of peanut by affecting calcium absorption of peanut.4、Foliar fertilization had little effect on the Alpha diversity of peanut phyllosphere microbial community,but significantly changed its community structure.Proteobacteria,Actinobacteria and Firmicutes were the phyla that constituted the peanut phyllosphere microbial community,and at the genus level,15 species with relative abundance greater than 1% were identified.Both ANOSIM and Adonis analysis results showed significant differences between treatments and PLS-DA analysis further found that there may be a certain succession relationship in the microbial community structure.Leaf total carbon content,calcium content and organelle calcium content were the main biochemical characteristics driving the phyllosphere bacterial community composition.Quadrisphaera,Pseudomonas,Thauera and Klebsiella were significantly different among the dominant species at the genus level.The correlation heat map showed that the dominant species at the genus level were closely related to peanut growth traits,carbon and nitrogen metabolism and calcium absorption.Sorbitol chelated calcium could promote the proliferation of Quadrisphaera in the phyllosphere,significantly changed the phyllosphere microbial abundance and community composition,which could directly or indirectly lead to changes in the phyllosphere microbial community structure,and ultimately affect leaf metabolism,nutrient absorption and yield.In conclusion,spraying foliar fertilizer on the basis of customary basal fertilizer could viably advance the development of peanuts and influence the yield and quality.Compared with other treatments,since sorbitol chelated calcium not only changed the calcium form,but also included the carbon source(sorbitol)and nitrogen source(nitrate nitrogen),and the wetting effect of sorbitol decreased its contact angle with peanut leaves.Therefore,it could significantly promote the absorption of calcium in leaves,change the distribution of calcium in mesophyll cells,and enhance the ability of carbon and nitrogen metabolism.This also directly or indirectly changed the phyllosphere microbial community structure and affected the plant-microbe interaction,which promoted the growth of peanut plants,accelerated the accumulation of dry matter,and finally improved peanut yield and quality.