五爪金龙茎的解剖结构

运用常规石蜡切片、显微观察及显微照相的方法,对五爪金龙(Ipomoea cairica)茎的结构进行了观察研究,结果表明:五爪金龙茎的解剖结构以初生结构为主,维管形成层已经形成,但次生结构尚不发达。通常具3~6个空腔,初步推断其为裂生式分泌道;表皮外弦向壁增厚,具角质层,具气孔及气室;紧贴表皮内方的1~3层和皮层最内1~3层的细胞可能为分泌细胞;具双韧维管束,木质部极为发达,导管细胞紧密排列,围绕内韧皮部和中央的髓而成一圆周;形成层位于外韧皮部与木质部之间;茎中央是大型薄壁细胞构成的髓,具簇晶。

Anatomical Structure of Stem of Ipomoea cairica (Convolvulaceae)

Anatomical structure of stem of Ipomoea cairica was observed in detail by using light microscopy. The results indicate that the anatomical structure of the stem of Ipomoea cairca compose mainly of primary structure, and the cambiums has formed, but the secondary structure is not well-developed. The stem of Ipomoea cairica usually bears 3-6 cavitys, which may be schizogenous secretory canals. The tangertial wall of epidermis cells gets ticker, and the epidermis has cutide, stomas and air chamber. In cortex, there are 1-3 layers of cells tightly next to the epidermis as well as the 1-3 layers of cells which are deep inside cortex, both of them are secretory cells. The vascular bundles are bicollateral. The xylem is well-developed, and the vessel elements arrange so closely that they become a circle surround the phloem and pith. In the middle of stem is the pith, which composed of abundant parenchymatous cells with rhombohedral crystals.