Effect Of Potassum Application On The Growth Characteristics And Polysaccharides Of Lilium Davidii Var.unicolor

Lilium davidii var.unicolor,as a sweet lily in China’s edible lily strains,is the first batch of plants approved by the Ministry of Health for both medicinal and edible purposes.Its economic value and medicinal value are very considerable.As the main edible part,bulbs are rich in active ingredients such as polysaccharides,and have important functional properties,which can participate in the immune regulation function and antioxidant of organisms.Therefore,improving the agronomic indicators of Lilium davidii var.unicolor and increasing its polysaccharide content are the main ways to increase its yield and improve its edible and medicinal qualities.In this study,Lilium davidii var.unicolor was used as the experimental material,a single-factor random design was adopted.Through Hoagland nutrient solution irrigation technology,under the condition of controlling nitrogen and phosphorus concentration,four K concentration levels were set to study the growth and development of potted Lilium davidii var.unicolor in greenhouse and the polysaccharide content of its different organs,aiming to provide theoretical guidance for improving its quality in production of high-quality and high-yield Lilium davidii var.The results of the study are as follows:1.From 30 to 75 days after fertilizer application,K application amount significantly promoted the growth of above-ground parts during the bud-appearance and flowering stages.The number of leaves,plant height,chlorophyll content and stem diameter of Lilium davidii var.unicolor grew best under K2（671.4 mg/L）treatment.From 120 days to 135 days after fertilization,the growth of Lilium davidii var.unicolor entered the half-withered period,and the bulb circumference and bulb weight increased significantly compared with the previous period.The K2（671.4 mg/L）treatment had the best effect on it,and was reached the peak during the whole growth period.K2（671.4 mg/L）treatment had the best effect on the agronomic traits.At the same time,the excessive K concentration in the late growth stage of Lilium davidii var.unicolor was not conducive to the accumulation of bulb nutrients.2.The application of potassium fertilizer increased the polysaccharide content of different organs of Lilium davidii var.unicolor to varying degrees.The content of polysaccharides in different sampling periods showed a certain difference with the increase of potassium application.The effect of K concentration on the polysaccharides of Lilium davidii var.unicolor bulbs showed the best effect was at the level of K2（671.4 mg/L）treatment,and the most accumulation was at the K3（895.2 mg/L）treatment in the late growth stage from 120 days to 135 days after fertilization.The peak of stems polysaccharide content appeared at the budding stage 45 days after fertilization,while the lowest content was found at the half-withered stage 135 days after fertilization.The content of polysaccharide in leaves was significantly higher at flowering stage than that in budding stage.The polysaccharide content in stem roots peaked at 120 to 135 days after fertilization when lily reached the half-withered stage,and accumulated the most under K2（671.4 mg/L）treatment.Correlation analysis showed that the bulb polysaccharide content was significantly and positively correlated with K concentration from 120 days to 135 days after fertilization.3.Metabolomic analysis of the bulb under K0 and K3 treatment at 45 days and at 135 days after fertilizer application detected 37 polysaccharide-related differential metabolites.After potassium application,there were 3 unique differential metabolites between K0₅ and K3₅,and 7 unique differential metabolites between K0₈ and K3₈,and the above metabolites were involved in 6 metabolic pathways.At 45 days after fertilization,the metabolites with higher relative content were Maltotriose,Maltohexaose,and 1-Kestose.At 135 days after fertilization,the metabolites with higher relative content were Maltopentaose,Maltotriose,1-Kestose,3-Fucose and Maltohexaose.