Analysis Of The Aroma Components And The Effects Of Shade Stress On The Growth And Development Of Sarcococca Ruscifolia

Sarcococca ruscifolia is a wild evergreen shrub with good smell and beautiful leaves and fruits.Its fragrance is special and S.ruscifolia could grow and develop very well under shade conditions.There are many genotypes of S.ruscifolia,which could be used widely in landscaping and has great development and utilization value.Up to now,researches about S.ruscifolia were most related with pharmacological constituents and biological characteristics.Studies about aroma composition analysis and effects of shade stress on growth of S.ruscifolia were almost not mentioned.In this research,aromatic components,and light compensation point（LCP）of S.ruscifolia compared with common shade-tolerant plants in Shanghai,were analyzed.The effects of wild medium and severe shade on growth of S.ruscifolia and mechanisms related with oxidative stress and metabolite accumulation were also analyzed.The results were as followed:1.The volatile components of S.ruscifolia introduced from Shanghai Chenshan Botanical Garden were detected and analyzed by Headspace solid phase micro-extraction and Gas Chromatography-Mass Spectrometry.19kinds of volatile components with relative content more than 1%were detected,among them,phenylethanol（22.94%）,n-hexane（9.76%）,indole（7.90%）,alcohol（6.13%）,3-methylfuran（5.87%）,basil ene（3.95%）might be the main components of volatile substances in S.ruscifolia.Phenylethanol,ethyl acetate,phenylethyl acetate and linalool might be the key aromatic components of S.ruscifolia.The volatile components of S.ruscifolia have good pharmacological actions,such as phenylethanol,ocimene,linalool,etc.The results of this study have laid a foundation for the popularization and application of S.ruscifolia.2.LPC of S.ruscifolia and 4 common shade-tolerance plants in Shanghai,including Fatsia japonica,Aspidistra elatior,Mahonia fortunei and Aucuba japchica var.variegata,were measured with Li-6800photosynthetic apparatus.It was found that LCP of S.ruscifolia were minium.It might have very high shade-tolerant and should be generalized as a shade-tolerant plant in Shanghai.3.The effects of 50%shade（medium shade,T1）and 90%shade（severe shade,T2）on the growth and development of S.ruscifolia at high temperature in summer were analyzed,compared with control（CK）.It was found that dry matter accumulation was significantly reduced and the total chlorophyll and carotenoid contents increased,chlorophyll a,chlorophyll b and chlorophyll a/b also increased significantly,under shade conditions in leaves of S.ruscifolia.Electrolyte leakages and malondialdehyde contents of leaves decreased under shade conditions,especially under T2 treatment.Shade reduced the accumulation of H₂O₂ and O₂^-in leaves of S.ruscifolia.The activity of superoxide dismutase decreased with the decrease of light intensity.The activities of peroxidase and ascorbate peroxidase in leaves increased significantly under T2 treatment.The accumulation of metabolites was analyzed by gas chromatography-mass spectrometry under different shade conditions.Based on database analysis,100 metabolites were identified,including 24 organic acids,22 amino acids,28 sugars,12 sugar alcohols,8 amine compounds and6 other compounds.Partial least squares discriminant analysis showed that shade significantly affected the accumulation of metabolites in leaves of S.ruscifolia.The accumulation of metabolites was also significantly different between T1 and T2 treatments.Under shade conditions,especially severe shade,the content of sugar increased significantly,especially galactose,fructose,glucose and sucrose.Pearson correlation coefficient was used for cluster analysis,combined with other three indexes,variable important of projection more than 1,having significant difference and fold change more than 1.5 compared with CK,9 metabolites were chosen,including fumaric acid,ferulic acid,alanine,threonine,sedoheptulose,galactose,ribofuranose,fructose and uracil.The accumulations of these 9 metabolites might be related with higher shade-tolerance of S.ruscifolia.