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利用巴西橡胶树无性系热研７－３３－９７苗圃芽接幼树为材料，采用光学显微镜技术和电子显微镜技术研究了初生乳管分化与茎叶发育的关系。研究结果表明，苗端最初的乳管的分化和原形成束的分化相伴发生，这些乳管出现在原形成束附近，束的近轴一侧。但是当维管形成层形成时，束间形成层在初生乳管的近轴一侧产生，因而随着次生形成层的活动，初生乳管被定位于次生韧皮部远轴一侧。茎和叶中的初生乳管系统和初生维管系统一样连接成一个整体。最初形成的初生乳管是有节连接乳管，随后这些乳管侧壁向各个方向发生侵入生长，互相连接成为一个不规则的立体网状结构。在一个叶蓬生长过程中，茎和叶柄横切面上初生乳管的数目在芽萌动至叶古铜期期间迅速增加，到叶淡绿期增长基本停止。在差不多经历一个生长季的茎部，才产生次生乳管。当次生乳管出现时，初生乳管由于茎的次生加粗而被拉伸，同时这些乳管在茎组织中分布的密度减少。笔者假定，这种正在变老的初生乳管会产生导致次生乳管分化的信息。
The relationship between primary ducts differentiation and stem and leaf development was studied by means of light microscopy and electron microscopy using the seedlings of budded sapling of the rubber tree Hevea brasiliensis 7-33-97 nursery. The results showed that the initial differentiation of the ducts and the formation of the original bundles occurred at the tip of the seedlings. These ducts appeared near the original formation and near the paraxial side of the bundle. However, as the vascular cambium is formed, the intercluster cambium is created on the paraxial side of the nascent lax tube, so the nascent labrum is positioned on the far axis side of the secondary phloem with the secondary cambium’s movement. The primary mammary duct system in the stem and leaf is the same as the primary vascular system. The primary nasolactum formed initially was an articulated mammary tube, which then invaded and grew in all directions and interconnected to form an irregular three-dimensional network. During the growth of a Phragmites communis, the number of primary ducts on the cross-section of the stem and petiole rapidly increased during the period from bud sprouting to leaf-bronze period, and basically stopped to the pale-green leaf period. A secondary mammary duct is produced only after almost one growing season. When secondary ducts appear, the primary ducts are stretched due to the secondary thickening of the stems while the density of these ducts distributed in the stem tissue is reduced. The authors hypothesize that this aging nascent duct will produce information that leads to secondary ductal differentiation.