| Eucommia ulmoides Oliv.is a single genus of Eucommia ulmoides(E.ulmoides)belonging to the genus Eucommia.It is a valuable Chinese medicinal material and the most widely distributed gum source species in the world.Its leaves,peels,bark and root bark all contain gutta-percha,which has strong acid,corrosion and wear resistance.It is a good natural rubber resource and has great development potential.gutta-percha particles are a class of organelles accumulated in the eucalyptus gelatinous cells.It has been confirmed that the rubber particles in the rubber gum of Brazil are important organelles for the synthesis and storage of natural rubber,and important research progress has been made.However,the formation mechanism of rubber particles in the rubber-producing plants for synthesizing trans isoprene such as E.ulmoides has not been elucidated.In this paper,the method of separating and purifying gutta-percha particles was studied by using E.ulmoides leaves and samara.The morphological structure of gutta-percha particles was observed,and the fatty acid composition of gutta-percha particles and the rubber molecular weight of rubber granules were determined to reveal the E.ulmoides rubber.The morphology and physiology of the particles provide a theoretical basis,the following results are obtained:1.Separation and purification of E.ulmoides rubber particlesE.ulmoides fresh tissue(blade or samara)in turn by the liquid nitrogen frozen,mashed six and 12 times after filtering centrifugal grinding,set at 45 degrees Angle centrifuge for 10 min at 4?condition 5 000 g centrifugal force,at last,by floating wash washing 10 times the income of the gutta-percha particles content is the highest.Under these conditions,gutta-percha granules were extracted from E.ulmoides tissues in different months,and it was found that gutta-percha granules content was the highest in leaves and samara of E.ulmoides in October,reaching 0.37g/100g and0.53g/100g,respectively.2.Observation of gutta-percha particles morphology and analysis of particle distributionThe microscopical observation of the separated and purified rubber particles showed that gutta-percha particles were spherical under both light microscope and electron microscope,and there were significant differences in particle sizes between the rubber particles.Taking the E.ulmoides samples collected in October as an example,the medium and small size particles(1?m-4?m)accounted for 39%of the total size,the medium size particles(4?m-7?m)accounted for 38%,and the large size particles(7?m-11?m)accounted for 23%.In the samara of E.ulmoides,the three accounted for 53%,34%and 13%of the total gum particles,respectively.The difference of gutta-percha particles in bark is more significant.The proportions of three kinds of gutta-percha particles are 98.38%,0.12%and 0.05%respectively.gutta-percha particles are mainly small ones.Through the determination of particle size of gutta-percha in different months,it was found that on the whole,the size and content of gutta-percha particles showed a trend of increasing first and then stabilizing with the development and maturity of gutta-percha leaves and samara.3.Analysis of fatty acid composition of gutta-percha granulesGC-MS was used to determine the fatty acid content of gutta-percha granules.It was found that the fatty acid composition and content of gutta-percha granules were different in different sampling months(August,October and November).3 months respectively to detect the 26,30,26 kinds of fatty acids,including 15 kinds of unsaturated fatty acid,palmitic acid(C16:0),24(C24:0),22 carbonic acid carbonate(C22:0),arachidic acid(C20:0),stearic acid(C18:0)and 23(C23:0),nutmeg acid carbonate(C14:0),17 carbon olefine acid(C17:0),21(C21:0)carbonate content is higher;Unsaturated fatty acids of 15 carbon olefine acid(C15:1),17 carbon olefine acid(C17:1),20 carbon triene acid(C20:3 n6),arachidonic acid(C20:4 n6)and eicosapentaenoic acid(C20:5 n3)and docosahexaenoic acid(C22:6 n3)and 24 carbon olefine acid(C24:1)to unique in E.ulmoides Ye Jiao particles,in October to 20carbon olefine acid 3(C20:3 n6)content is the highest,up to 0.180 mg/g.Variance analysis results show that E.ulmoides Ye Jiao particles in August in saturated fatty acids and unsaturated fatty acid content difference was not significant,and in October and November of rubber particles in barks of E.ulmoides oliv respectively achieved significantly(P<0.05)and significantly(P<0.01)difference level,as the eucommia bark leaf development and mature of the rubber particles(saturated and unsaturated fatty acid content with significant difference.In addition,29 fatty acids were detected in eucommia samara gum particles in October,including 14 saturated fatty acids and15 unsaturated fatty acids.The contents of methyl palmitate(C16:0),stearic acid(C18:0),methyl arachidate(C20:0),docosanoic acid(C22:0)and tetracosanoic acid(C24:0)were higher in the saturated fatty acids.The results of variance analysis showed that there was no significant difference in the content of saturated fatty acids between Eucommia samara and leaf gum particles collected in October.4.Molecular weight analysis of gutta-perchaThe determination of molecular weight of gutta-percha particles in E.ulmoides leaves and samara gum particles in October indicated that there were 5 peaks in the mass distribution of rubber molecules in gutta-percha particles in leaves,namely P1,P2,P3,P4 and P5.The samara shows two to three peaks,P1,P2 or/and P3,respectively.Among them,gum particles of E.ulmoides leaves high molecular weight(P1)adhesive molecular average molecular weight(?)of 60.9×10~4,significantly(P<0.05)than fruit high molecular weight of the bark of Eucommia cortex gum molecules average molecular weight(49.58×10~4),the second-highest in barks of E.ulmoides oliv gutta-percha molecular average molecular weight(1.61×10~4)significantly(P<0.01)than in the extraction of fruit second-highest gutta-percha molecular weight(0.48×10~4).However,further determination of the average molecular weight of gutta-percha in E.ulmoides leaves and samara showed that the average molecular weight of gutta-percha in leaves was significantly lower(1.83×10~4)(P<0.05)than that in E.ulmoides leaves(4.15×10~4).Found that calculated using the adhesive molecular distribution of E.ulmoides samara gutta-percha molecular weight distribution(D=Mw/Mn)than the leaf width,E.ulmoides leaves and barks of E.ulmoides oliv samara D value were 6.06 and 40.61,it is indicated that although the molecular weight of rubber molecules of different sizes in E.ulmoides rubber particles is more,the relative molecular mass distribution of rubber is more concentrated,while the molecular weight of rubber with different molecular weights in the samara rubber granules is less,but the distribution is more dispersed. |
PDF Full Text Request