文档介绍：橡胶树枝条初生乳管形态发育研究
摘要:橡膠树的初生乳管主要存在幼嫩树干、枝条、叶片、花和果实中,其发育过程依然不清楚。本研究利用石蜡制片和改良的碱处理剥离2种方法研究了幼嫩枝条初生乳管的形态发育过程,发现碱处理剥离法能观察rowth was not obvious. The lacifers at 7 cm away from the apical meristem had obvious intrusive growth and bead-like structures, which resulting in increase in the diameter of laticifers. The laticifers at 14 cm away from the apical meristem were significantly enlarged in diameter, and contained more bead-like structures, and the bead-like structures between the neighboring laticifers were connected to form laticifer bridges, which resulting in the formation of a laticifer network. The laticifers isolated from different positions of the stable-stage shoots were morphologically similar, and the density of the protrusions or bead-like structures and the laticifer bridges was significantly higher than that in bronze-stage shoots, and complex laticifer networks were formed in the barks at all positions. The primary laticifers were proved to be multinuclear as well. The results of this study indicate that the primary laticifers in the rubber tree shoots are non-articulated and anastomosing, and belong to a novel type of laticifers. This study would play an important role in the fundamental research of the plant laticifer development. Keywords: Hevea brasiliensis Muell. Arg; primary laticifer; novel type of laticifer; non-articulated and anastomosing laticifer
DOI: .1000-
橡胶树(Hevea brasiliensis)属大戟科橡胶属,是热带地区重要的经济作物。据不完全统计,全球产胶作物12500多种,由于橡胶树所产天然橡胶具有产量高、易采收、质量好等优势[1],是商品天然橡胶的主要来源。
乳管是指一种含有胶乳的特化细胞或一列含有胶乳的并合细胞[2],它也是橡胶树胶乳生物合成、贮存和运输的场所[3]。橡胶树的乳管分为2种类型,初生乳管和次生乳管[4-5]。初生乳管是植物体初生生长时形成的乳管,主要存在橡胶树的幼嫩树干、枝条、叶片、花和果实中,而次生乳管主要存在树干中[6-7]。橡胶树中初生乳管的胶乳含有一些有毒物质,如羟基***水解酶,可用来催化***基类化合物水解,释放氢***酸,抵御害虫和病原菌的侵害[8]。
目前尚欠缺对橡胶树初生乳管系统发育的研究。吴继林等[4]采用石蜡制片的组织化学染色法研究橡胶树幼茎中初生乳管的发育,认为其为有节联结乳管;而采用剥离的方法观察到幼茎中初生乳管具有很多长的分枝,认为橡胶树初生乳管为无节乳管[9]。导致这些研究结果的差异可能是由于研究方法和研究材料的差异所造成。本研究采用了改良的碱处理剥离法,系统研究橡胶树枝条不同发育时期、不同部位初生乳管的形态特征,克服了前人研究的局限性,发现橡胶树初生乳管属于一种新型乳管类型