空心莲子草根中异常结构及不定芽的发育解剖学研究

The developmental anatomical study on anomalous in the root and adventitious buds of Altemanthera philoxeroides

运用光镜和扫描电镜的方法 ,观察了空心莲子草根的结构及不定芽的结构 ,结果表明 :根的初生木质部为二原型、三原型和四原型 ;初生结构和早期次生结构正常 ,异常的次生生长是由于次生韧皮部外侧发生的额外形成层所致 ,后一轮额外形成层起源于前一轮向外产生的薄壁细胞 ,结合组织为发达的薄壁细胞 ,二至四轮三生维管束排成整齐的同心环类型 ,不定芽主要起源于异常根的额外形成层 ,芽外有二至三轮鳞片 ,其内着生许多毛状物。

The structures of the root and adventitious bud of Altemanthera philoxeroides have been observed with light microscopy and electro-microscopy. The results showed that the primary xylem of the root is diarch, triarch and tetrarchy; the primary and early secondary structures are normal. The anomalous secondary thickening results from supernumerary cambium derived from the outmost elements of secondary phloem. The following supernumerary cambium initiates in the parenchyma derived from the outmost immediate preceding ring. The connective tissues are developing parenchyma with two-four regular and concentric rings of collateral tertiary bundles. Adventitious bud mainly originates from the supernumerary cambium of the anomalous root. There are two or three rings scales outside the bud, within which many hair-like things are insertional.