摘要
运用光学显微镜和扫描电镜的方法,对水花生的根、茎、叶营养器官进行比较观察。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,二-四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;水花生茎有气腔,薄壁细胞间有间隙,形成层细胞层数多。地下茎比较粗,形成层细胞层数少,薄壁细胞较大。地下茎加粗过程中形成三生结构,其异常结构是由于次生韧皮部外侧发生的额外形成层所致,其起源于薄壁细胞;水生叶与旱生叶在栅栏组织与海绵组织的分化以及维管束之间的薄壁细胞大小方面存在差异。由于特殊的解剖结构,水花生很强的生态适应性。
Comparative observation of vegetative organs of Alternanthera philoxeroidles was performed with the optical microscope and the scanning electron microscope. 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 in- itiates 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. The results showed that pith of stem in hydrophilic is bigger than in drought. And the clearance among parenchyma in hydrophilic is also larger than in drought. The results also showed that the parenchyma in hydrophilic forms aerechyma and the cambium in drought is much more. The hypogeal stem is wider than the aerial shoot and the cambium reduces. The growth of hypogeal stem contain tri-growth, and the anomalous secondary growth is the result of supernumerary cambium that derived from the outmost elements of secondary phloem. And the supernumerary cambium derived from parenchyma. Adventitious bud mainly originates from the supernumerary cambium of the anomalous root. The differences be-tween the hypogeal leaf and the aerial leaf are the inverse proportion of the paslisade and spongy tissue, as well as the size of the parenchyma among the vascular cylinder.
出处
《江苏农业学报》
CSCD
北大核心
2005年第4期277-282,共6页
Jiangsu Journal of Agricultural Sciences
基金
江苏省十五攻关项目(BE2001348)
关键词
水花生
根
茎
叶
解剖学
生态适应性
Alternanthera philoxeroides
root
stem
leaf
anatomical
ecological adaptation
