Physiological Characteristics And Aroma Components Analysis Of An Aromatic Paeonia Lactiflora

Paeonia lactiflora Pall.is a famous flower in China.It has a long history of cultivation,and has many kinds of varieties and colors.Its roots are crisp and juicy which can be used as medicine.Paeonia lactiflora is a natural antioxidant resource,and its floral essential oils can be used in medicine,food processing,cosmetics and other industries.It has high medicinal value and economic value.The ordinary peony species has a light aroma.We found a strong aromatic peony in Qin Ling,so whether this is a new peony varieties?Therefore,we study its morphological indicators,photosynthetic characteristics,aroma components,aroma-related genes,etc.,in order to provide basic data for identification of new varieties.The results are as follows:?1?We compared the photosynthetic characteristics of aromatic peony and ordinary peony.The net photosynthetic rate of two Paeonia lactiflora varieties are bimodal,with a lunch break.The non-right-angle hyperbolic model fits the light response curve of two Paeonia lactiflora varieties well,and the coefficient of determination is the largest of the four models.Paeonia lactiflora has a light saturation point greater than 2200?mol·m-2s-1 and belongs to the plants that need a lot of sunlight.In terms of chlorophyll fluorescence,Fm?dark adaptation maximum fluorescence?,Fv/Fm?dark adaptation maximum PSII?,Fv?dark adaptation variable fluorescence?,Fo'?minimum fluorescence yield under light?,and Fs?Steady-state fluorescence intensity?is significantly greater than that of ordinary peony,and Fo?dark adaptation minimum initial fluorescence?is significantly smaller than that of ordinary peony.?2?Successfully extracted the floral essential oils of petal tissues from aromatic peony and ordinary peony.49 kinds and 31 kinds of substances were detected from aromatic peony flower essential oil and ordinary peony flower essential oil,including 8 kinds of aroma substances.Among them,geraniol had the highest abundance,and the relative content of geraniol in the aromatic Paeonia lactiflora?up to 30.79%?was significantly larger than that of ordinary Paeonia lactiflora?only 16.44%?.?3?The GPPS and APS genes were cloned from the aromatic Paeonia lactiflora,and the sequences were highly consistent with the known genes.These two genes are involved in terpenoid metabolism in plants.Bioinformatics analysis was performed on them.The GPPS protein is predicted to be a hydrophobic extra-membrane stable protein,possibly a mitochondrial secreted protein,and subjected to multiple sequence alignment and phylogenetic tree construction.It is proved that terpene synthesis pathway exists in aromatic Paeonia lactiflora.?4?In order to successfully propagate the aromatic Paeonia lactiflora,the selection and treatment of tissue culture explants,the formulation of culture medium and sterilization method of Paeonia lactiflora were explored.It was found that the underground bud was a good explant of Paeonia lactiflora.By reducing the contact area of explant and culture medium,reducing the volume of explant and adding Ca Cl₂·2H₂O,the browning rate,bacterial infection rate and vitrification degree could be effectively reduced.There are endophytes in Paeonia lactiflora,but the content of Endophytes in the undegerminated lateral buds is low and the tissue activity is high.In vitro culture of the non-germinated lateral underground buds,it was found that the rate of bacterial infection could be reduced from 60%of the whole culture to 5%,and the survival rate of tissue culture could be effectively improved.