杜仲中反式聚异戊二烯分布和积累的组织化学研究

The distribution and accumulation of Eucommia ulmoides rubber(EUR)in the leaves,barks,and fruit coatings of Eucommia ulmoides were investigated.The physicochemical properties of EUR in different organs,the relationship between rubber particles(RP)and Eucommia ulmoides rubber-containing cells(EC)with tissues,as well as the spatial localization of EUR accumulation were analyzed.From April to October 2022,in Northwest A&F University,Yangling,arbor forest model of Eucommia planting and using leaf model of Eucommia planting Base were studied.EUR was extracted from leaves,barks and fruit coatings,and the EC were observed and separated in situ,as well as histological sections and chemical staining.The EUR was characterized by GPC,DSC,FTIR and 1H-NMR,and the tissue sections were observed by FM,SEM,TEM and CLSM.The characteristic parameters of EC and RP at different locations were measured,and the density and size of EUR at different locations were measured to analyze the formation and development of EC.Establish RP accumulation model in EC.The results show that 1)The difference of EUR in the leaves,barks,and fruit coatings of Eucommia ulmoides at the cellular scale is mainly reflected in the density,cross section size and distribution location.The density and cross section of the fruit coating generally exceed those of the bark,which in turn exceed those of the leaf.2)The differences in the shape of rubber particles are mainly reflected in the subcellular scale.The RP in the leaves of Eucommia ulmoides is mainly spherical and ellipsoidal,while the RP in the skin and seed shell of Eucommia ulmoides is capsules,spheroids and ellipsoids.3)EC in mature Eucommia ulmoides leaves,barks,and fruit coatings is generally enlarged at both ends,with a slender filamentary shape in the middle,and a few ECs have a node in the middle.In the developing Eucommia ulmoides leaves,barks,and fruit coatings,in addition to the above two shapes,there are also ECs with multiple expanded points,which are usually filled with little or no RP.In the development process of EC,it generally goes through three stages,the first stage is a small amount of RP generated in the EC,the second stage is a large amount of RP generated in the EC,and the RP and the EC will gradually grow larger,and the RP in the bark and fruit coating may develop from a spherical or ellipsoidal shape to a capsule shape.In the third stage,the RP is highly polymerized to form a main body,at which point the EC is fully mature.RP has two forms including multiple voids in the middle and no voids.A small number of RPs may have cavities inside mature ECs because the intermediate cavities are not completely filled.The number and area of EC in barks were closely related to the thickness and location of bark,while the number and area of EC in leaves were closely related to the size of leaves.The double-peak EUR molecular weight in Eucommia ulmoides leaves is due to the high molecular weight concentration in the main vein and the low molecular weight concentration in the branch vein.