Study On Flower Color Changes And Physiological Changes During Flowering Of Three Chimonanthus Praecox(L.) Link Cultivars

Chimonanthus praecox(L.)Link was a traditional precious tree native to China,with a rich variety of floral colors,a long history of cultivation and flower culture,and had excellent ornamental characteristics,cultural value,and application prospects.Using the medium and inner petals of three Chimonanthus praecox cultivars(’Jinyan lianjuan’,’Meirenzui’,and’Xiaoye’)at five stages()as the research object,this study comprehensively analyzed the changes in floral colors phenotype data,petal epidermal cell morphology,and physiological and biochemical characteristics during the flowering process of the three cultivars,as well as the differences during the full flowering stage of the three cultivars,using correlation analysis and principal component analysis to explored the of C.praecox floral color changes regularity and the relationship between floral color changes and physiological changes,in order to provide a reference basis for floral color improvement and variety classification of the three C.praecox cultivars.The main research results of this experiment were as follow budding,germination,initial flowering,full blooming and final flowering s:(1)With the changed of floral color,the magnitude of floral colors changed in the three C.praecox cultivars is not consistent.’Jinyanlianjuan’ had a smaller change in floral color than ’Meirenzui’,’Xiaoye’,and the changed in inner petal is more significant than that in medium petal.The medium and inner petals of ’Jinyanlianjuan’ changed from yellow-green to yellow,with chromaticity values decreasing.The medium and inner petals of ’Meirenzui’changed from yellow-green with a red flush to yellow,with inner petal a*significantly decreasing.The medium petal of ’Xiaoye’ changed from yellow-green with a red flush to yellow,with b*significantly decreasing.(2)The petal epidermal cell morphology of the three C.praecox cultivars was flat,and was not directly related to floral color changes,but there were some differences in cell size and epidermal patterns.Buding to final flowering stage,the water content of the epidermal cells was lost with the petals age,causing the center to sink,and the boundaries between cells become clearer.There were wax protuberances and coatings on the epidermal cells of all petals.(3)The medium and inner petal of the three C.praecox cultivars all contained flavonoids,carotenoids,and chlorophyll,and the ’Meirenzui’,’Xiaoye’ with a red flush petals contained anthocyanins,the flower pigments of the three cultivars were mostly flavonoids.The content of flavonoids and carotenoids had a significant effect on the yellow color change,and the content of anthocyanins had a significant effect on the red color change.(4)Soluble protein had a certain promoting effect on the synthesis of flavonoids,carotenoids,and anthocyanins,with a more significant effect on the synthesis of anthocyanins.The soluble sugar and chlorophyll in the medium petals of ’Jinyanlianjuan’ and ’Xiaoye’ were significantly positively correlated with carotenoids.They have a significant impact on the color change of flowers,but have no obvious effect on the synthesis of anthocyanins.SOD had a certain relieving effect on the flower aging of the medium and inner petals of ’Meirenzui’ and ’Xiaoye’,but has no significant effect on ’Jinyanlianjuan’.The inner of ’Meirenzui’,the medium and inner petals of ’Xiaoye’ had the highest content of anthocyanins during the bud stage,and the pH value is the lowest,indicating that the stability and content of anthocyanins are stronger under low pH conditions.The higher the pH of the ’Jinyanlianjuan’,the more obvious the yellow color is.(5)The PAL and CHI activity of the three C.praecox cultivars were higher in the early flowering stage,and the pigment synthesis metabolism was more active,so the pigment content was higher during the bud and germination stages.PAL and CHI activity was significantly positively correlated with the content of flavonoids and anthocyanins,and the higher the activity,the more beneficial it was to the synthesis of pigments,especially for anthocyanins.PAL and CHI activity had an impact on the color change of the three C.praecox cultivars,but the correlation coefficient between CHI activity and chromaticity was higher than that of PAL,indicating that it had a more significant impact on the color change.(6)The comprehensive correlation analysis and principal component analysis indicated that the main pigments that affected the color change of the medium and inner petals of’Jinyanlianjuan’,the medium petal of ’Meirenzui’ and ’Xiaoye’ were flavonoids,carotenoids,and chlorophyll.The main pigments that affected the color change of the inner petal of’Meirenzui’ and Xiaoye’ were anthocyanins,flavonoids,carotenoids,and chlorophyll,but the changing in anthocyanin content had the most direct effect.Soluble protein,soluble sugar,plant pH,SOD,PAL,and CHI also played an important role in the process of color change.Regarding the subsequent flower color improvement and breeding of C.praecox,in addition to directly changing the content of anthocyanins,flavonoids,carotenoids,and chlorophyll,the pigment content in the petal can also be regulated by adjusting the content of proteins and sugars in the petal cells,regulating the pH of the cytoplasm,or changing enzyme activity,to achieved the purpose of flower color improvement.