Study On Plant Volatile Constituents By Using Metabolomics Strategy

Plant metabolomics is an important branch of metabonomics,the study of it was very active in recent years.The volatile organic compounds(VOCs)is an important part of plant secondary metabolites,when plant in different growth periods,at different conditions,or under different exogenous stimulation,the qualitative and(or)quantitative of VOCs will change.The chemical constituents were identified,the change of VOCs was analyzed.This studies can make contribution to the analysis of plant secondary metabolism network,plant defense responses,division of plant classification to a certain extent.In this paper,the effects of VOCs Cyclamen persicum and Plectranthus tomentosa were investigated by means of solid-phase microextraction(SPME)coupled with gas chromatography-mass spectrometric(GC-MS)based on the plant metabolomics strategies.The main contents are summarized as follows:(1)The volatile constituents of fragrance released from the Cyclamen persicum were investiged by means of SPME coupled with GC-MS.The SPME parameters such as extraction fiber and extraction time were investigated.A total of 40 volatile compounds emitted from fresh flowers of Cyclamen persicum were separated and identified.The main volatile fragrance from fresh flowers of Cyclamen persicum in different florescence((A)flower buds;(B)at the early stage of flower blooming;(C)during the flower blooming;(D)senescence)were studied.And chemical constituent contents of flowers were increased with blooming reached a maximum when full blooming stage then decreased.The results demonstrated that SPME-GC-MS afforded a simple,rapid and solvent-free sampling method for identification of the main volatile fragrance from fresh flowers.The results provide scientific basis for the devopment and utilization of Cyclamen persicum.(2)The volatile constituents released from the plant of Plectranthus tomentosa which under standing?touching and wounding three states were investigated.A total of 54?59?60 volatile compounds were separated and identified under three states respectively.The main components of static state were D-limonene(49.84%),Nonanal(10.55%),Eucalyptol(9.90%);D-limonene(44.36%),Eucalyptol(8.48%),Pelargonic aldehyde(3.01%)at touching state;After mechanical damage the most abundant volatiles were D-limonene(28.29%),Eucalyptol(1.68%),Fenchyl alcohol(11.69%)etc..The results showed:After touched and wounded two abiotic stimuli,the volatile emissions would increase significantly,which the latter were more than the former.Compared with static state,after touched the relative content of each compound is basically the same;after mechanical damaged,the relative content of various compounds appears of different level changes,terpenes compounds content decreased obviously,and alcohols content increased obviously.The content change of total and each compound released from plant induced by mechanical damage have obvious regularity.(3)Plectranthus tomentosa was treated with different concentrations of heavy metals Cu solution and copper mixed with salicylic acid(SA),jasmonic acid methyl ester(MeJA)respectively.The change of VOCs released from Plectranthus tomentosa with different concentration of Cu,and the mitigative effect with SA,MeJA on poison of Cu were discussed.The results showed that heavy metal stress of Cu would make plant produce toxic effects,as the concentration increased,the content of terpenes decreased,and the content of alcohols,ketones showed the opposite results.With the time increasing,the content of alcohols,ketones increased,and the trend of terpenes were first decreased and then increased.The laws of volatiles released were different with Cu+SA and Cu+MeJA.The content of terpenes and others decreased obviously with stress treatment of Cu,and which would increase by different degree with the addition of SA and MeJA;ketones showed the opposite result.To sum up,exogenous SA.MeJA could be used as a potential growth regulator to improve the tolerance of the plant to the Cu toxicity.