Physiological Change And Analysis Of Differential Metabolites Of Mother Bulb During The Growing Periodof Lilium Davidii Var. Unicolor

Lilium davidii var.unicolor,an important genus of lilies(Lilium spp.),has very high economic value,ornamental value and medicinal value.It is the only sweet lily among the four strains of edible lily.However,there are relatively few systematic studies on the physiological changes during the growth and development of L.davidii var.unicolor.Therefore,this study researched the physiological changes of bulbs,roots,stalks and leaves during the development of L.davidii var.unicolor.At the same time,we analyzed thechange of differential metabolites in mother bulbsduring the development of L.davidii var.unicolor by non-target metabolomics,so as to provide a theoretical basis for clarifying the growth and development rules of lily and the relationship between the change of metabolites in lily and the development of bulbs.The main results and conclusions are as follows:1.In August,the photosynthesis of L.davidii var.unicolor was the strongest,and the accumulation rate of photosynthetic products was faster,so the chlorophyll content,maximal photochemical efficiency of PS II(Fv/Fm),actual photochemical efficiency of PS II(YII),fresh weight of leaves and stalks and total weight of plant in L.davidii var.unicolor all reached the maximum.Before August,the fresh weight of mother bulbs increased quickly,while the daughter bulbs mainly increased in number.After August,the daughter bulbs began to absorb nutrition for swelling and getting weight.2.The contents of soluble sugar and starch in mother bulbs and daughter bulbs were significantly higher than those in roots,stalks and leaves.The contents of sucrose and soluble sugar in L.davidii var.unicolor all showed a serrated change.From June to August,sucrose and soluble sugar in mother bulbswere mainly consumed.The starch in the leaves was decomposed into other carbohydrates firstly,which were used for the growth of leaves,stalks,roots and bulbs and then used for the accumulation of carbohydrates in the leaves.Carbohydrates in the stalk began to accumulate to promote the growth of itself.The consumption of sucrose and starch in the root was converted into soluble sugar for the growth of itself,stalks,leaves and bulbs.The content of starch in mother bulbs and stalks,soluble sugar in roots,stalks and leaves were the highest due to the highest photosynthesisrate in August.From August to October,the contents of starch,sucrose and soluble sugar in mother bulbs changed significantly,starch in the mother bulbs began to be consumed and converted into sucrose and soluble sugar.The content of soluble sugar and starch in the stalk decreased,the reason of which was that the soluble sugar and starch may be used for the growth of bulbs,or their synthesis rates decreased due to the wilting.There was a mutual conversion among starch,sucrose and soluble sugar in roots.From August to September,sucrose and soluble sugar in leaves may be used for the synthesis of starch.The contents of fructose,glucose and maltose in mother bulbs,roots,stalks and leaves of L.davidii var.unicolor all showed a serrated change.The contents of fructose in mother bulbs,roots,stalks and leaves varied significantly in different months.The content of glucose in mother bulbs increased significantly in August,September and October.August was the turning point of physiological changes of L.davidii var.unicolor.There was a significant period of physiological changes from August to October in L.davidii var.unicolor.3.493 metabolites were identified and 141 different metabolites were screened in August,September and October.There were 45 common differential metabolites in the differential metabolites of mother bulbs between August,October and September,October.There were 25 common differential metabolites in the differential metabolites of mother bulbs between August,September and August,October.There were 17 common differential metabolites in the differential metabolites of mother bulbs between August,September and September,October.There were 5 common differential metabolites in the differential metabolites of mother bulbs among August and September,September and October,August and October.The above-mentioned differential metabolites played a very important role in promoting energy synthesis and material metabolism in L.davidii var.unicolor bulbs at different development stages.4?There were 8 common metabolic pathways in differential metabolites of mother bulbs between August,October and September,October.There were 18 common metabolic pathways in differential metabolites of mother bulbs between August,October and August,September.There were 5 common metabolic pathways in differential metabolites of mother bulbs between August,September and September,October,including Biosynthesis of secondary metabolites,Stilbene compounds,biosynthesis of diarylheptane and gingerol,Flavonoid biosynthesis,Starch and Sucrose metabolism,Phenylpropanoid biosynthesis.There was 1 common metabolic pathway in differential metabolites of mother bulbs among August and September,September and October,August and October,which was phenylpropane biosynthesis pathway.These metabolic pathways and the enriched differential metabolites played an important role in the development of L.davidii var.unicolor bulbs,and provided important information for us to study the changes of metabolites in bulbs during the development of L.davidii var.unicolor.5?15 differential metabolites including chlorogenic acid,camptothecin,coumarin,vitamin C,riboflavin,homogentisic acid,salicylic acid,L-valine,L-aspartic acid,sarcosine,serotonin,indole-3-acetamide,guanine,arbutin,trehalose,were enriched in several metabolic pathways during the development of mother bulbs.These differential metabolites played an important role in improving plant resistance,resisting environmental stress,forming proteins,promoting bulb swelling,delaying plant senescence,regulating sucrose and starch metabolism,etc.