Comparison And Identification Of Quality And Flower Color Difference Between Edible Chrysanthemum ’Pink Candy’ And Bud Sport ’Yellow Candy’

Chrysanthemum,as one of the top ten famous flowers in China and one of the world four cut flowers,.not only has ornamental value but also has certain edible and medicinal value.However,at present,the edible chrysanthemums in China are homogeneous on color and application.In order to innovate and increase germplasm resources of edible chrysanthemums,we intruduced several new edible varities of chrysanthemums from China Agricultral Univeristy.During the cultivation,a natural bud sport of ‘Pink Candy’(short for PC)was found by accident.After separation and propagation,we obtained the natural color-changed bud mutant material and named as ‘Yellow Candy’(short for YC).In our study,we compared and indentified the differences of edibleness and color between PC and YC.The details are as follows:1.The edible differences between PC and YC: the content of soluble sugars,polyphenol and soluble proteins in the petals of YC were significantly increased by 35.27%,53.08% and26.07%,respectively,compared to PC.The secondary metabolites,such as naringin,luteolin and coprinin in YC were 58.05%,98.73% and 93.24% higher than those of PC,respectively.The catalase activity(CAT)in the petals of YC was 26.50% higher than that of PC,with a significant difference.Aroma components determination showed that PC contained high special aroma components 2-hexenal and corsalone,the content was 505.98 ng/g and 428.54ng/g,respectively.The principal component analysis(PCA)and membership function analysis(MFA)showed that four nutritional value indexes,namely soluble proteins,chlorogenic acid,apigenin and amino acid,could be used as main indexes for evaluating the edible value of chrysanthemums and the high composite score of principal component of YC and the consistent composite membership function score proved its high edible value.2.Exploration of the cause of color differences between PC and YC: chemical reagent color reaction assays were performed to determine the kind of pigments preliminarily.Then several main pigments in the petals of PC and YC were measured.The result showed total flavone and anthocyanins in PC were about four-and six-fold of those in YC,while the content of total carotenoids and lutein in petals of YC were about increased by 150.89% and 61.45%,respectively,as compared to PC.Furthermore,the q PCR test of carotenoid and anthocyanin biosynthesis genes showed the relative exprssion of Cm PAL in YC was significantly increased,but the expression of anthocyanin biosynthesis genes Cm F3 H,Cm FLS and Cm DFR were decreased,in comparison with PC.While,the relative exprssion of Cm LCYE and Cm ECH were significantly increased in YC,and the expression of Cm NXS and Cm CCD4 were decreased sharply in YC,compared to PC.To some extent,the distinct differences of the expression of these genes resulted into the color difference between PC and YC.The relative analysis of the tested components showed that the expression of Cm LCYE was negatively correlated to terpenes and aldehydes in aroma,as well as the content of flavonoids,but was positively related to the content of Lutein.There was a certain connection between aroma compounds like terpenes,alcohols and flavonoids in petal.The expressions of genes related to pigment biosynthesis were a certain extent affecting the content of nutrients and aroma substances in petals.Taken together,the bud sport YC was much more nourishing,with a higer edible value than its parent PC.The differences of the content of pigments,as well as the distinct expressions of pigment biosynthesis genes were the main cause of the color change of YC.