油松茎次生结构中树脂道的结构分布和发育的研究

油松茎的次生结构中树脂道存在于次生维管组织中。其中,次生木质部内具有水平的和垂直的两类树脂道,而次生韧皮部内则仅有水平的树脂道。两类树脂道都由上皮细胞和鞘细胞包围着胞间道构成,其中木质部内的树脂道具有死鞘细胞,而韧皮部中的则都系生活细胞。在心材中,垂直树脂道形成拟侵填体。在次生木质部内,垂直树脂道常分布于早材的外部区域和最初形成的晚材中,它们与水平树脂道连接,腔道贯通,从而形成二维网状结构。垂直树脂道来源于纺锤状原始细胞的衍生细胞,而水平树脂道来源于射线原始细胞,两者都以裂生方式发生。

THE STRUCTURE, DISTRIBUTION AND DEVELOPMENT OF THE RESIN DUCTS IN THE SECONDARY STRUCTURE OF STEM OF PINUS TABULAEFORMIS CARR

Resin ducts were found in the secondary vascular tissues of stem of Pinus tabulaeformis Carr.. In the secondary xylem vertical and horizontal ducts are present, but in the secondary phloem only horizontal canals occur. The resin ducts are elongated structures developed throughout their length of epithelial cells surrounding an intercellular space. In the ducts of the secondary xylem some dead sheath cells are present, but all of the sheath cells in the secondary phloem are full of protplasm. The tylosoids in vertical canals occur in heartwood.In the secondary xylem, the vertical ducts of each (?)growth-ring usually appear in the outer region of early wood and in the first formed late wood. The inner end of each radial duct is connected to a vertical duct of the secondary xylem, and the lumina of the two types of ducts are continuious. The networks thus formed are only two-dimensional. The vertical resin ducts are derived from the daughter cells of the fusiform initials, while the horizontal ones from those of the ray initials. Both of them were found to form shizogenously.