BACKGROUND Hydraulically efficient xylem was evolved in the vascular plants as an apomorphy of the group. Main xylem components involved in water conduction are tracheid and vessel. Vessels, in which two ends are perforated, constituted major evolutionary innovation within vascular plants, presumably providing more efficient solute conduction. Not all vascular plants have vessels. In pteridophytes vessels are present only in seven genera. The contention lies regarding the presence and distribution of vessel in pteridophytes are the impulsive force of this investigation. METHODS Tracheary elements are isolated following the standard maceration technique, then hand-razor cut longisections are passed through the aqueous alcohol grades and air-dried samples are placed on stub, sputter coated with gold and examined with SEM. RESULTS Two thelypteroid ferns viz. Ampelopteris prolifera (Retz.) Copel. and Thelypteris interrupta (Willd.) K. Iwats. are having vessel elements in root, rhizome, stipe, rachis, primary vein/costa, root-rhizome and rhizome-petiole junction i.e. through entire vascular connection of the plant body though the vessel network is interrupted and joined with parenchyma at the end in some places. Presence of vessel elements in the costa of pteridophytic taxa is first time reported by this study. Vessel end-walls are obliquely placed (root, rhizome, and stipe) but oblique to horizontal orientation is noticed in the primary vein/costa. End-walls are with simple, intermediate and compound perforation plates observed through SEM imaging as well as with tissue specific stain. Studied taxa are grown either in terrestrial microclimate of two contrasting environments i.e. sun and shade (A. prolifera) or in open swampy land (T. interrupta) with moderate to highly disturbed places as rapid proliferating populations showing interpopulation variations of tracheary elements length-width(s) and vessel end-wall length-width(s). CONCLUSION Vessel elements are present throughout the entire vascular connections of the plant body of A. prolifera (Retz.) Copel. and T. interrupta (Willd.) K. Iwats. Interpopulation variation of tracheary elements length-width(s) and vessel end-wall length width(s) are noticed. Till date only seven genera of pteridophytes are reported for the presence of vessel and these two genera are the new addition with the previous.

中文翻译：

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两个类蝶类蕨类植物的容器元素-第一部分

背景技术水力有效的木质部在维管植物中进化为该群体的阿朴体。参与水传导的主要木质部成分是气管和血管。两端穿孔的血管构成了维管束植物的主要进化创新，推测可以提供更有效的溶质传导。并非所有维管植物都有血管。在蕨类植物中，血管仅存在于七个属中。争论在于蕨类植物中血管的存在和分布是这项研究的推动力。方法按照标准浸没技术分离气管元素，然后将手工剃刀切开的横切面通过水性酒精等级，将风干的样品放在存根上，溅射镀金并用SEM进行检查。结果两个类蝶类蕨类植物。Ampelopteris prolifera（Retz。）Copel。和Thelypteris interrupta（Willd。）K. Iwats。在根，根茎，柄，轴，主静脉/肋，根-根茎和根茎-叶柄的​​交界处具有脉管元素，即通过植物体的整个脉管连接，尽管脉管网络被打断并在最后与薄壁组织结合的地方。这项研究首次报道了在蕨类植物类群的肋骨中存在血管元素。血管端壁倾斜放置（根，根茎和刀柄），但在主静脉/肋骨中注意到水平倾斜。端壁带有通过SEM成像观察到的简单的，中间的和复合的穿孔板以及组织特有的污渍。研究的类群既可以在两种相反环境的陆地小气候中生长，即在阳光和阴影下（A. prolifera），也可以在中度到高度扰动的开阔沼泽地（T. interrupta）中生长，因为快速繁殖的种群显示出气管要素长度-宽度的种群间变化。 （s）和容器端壁的长度-宽度。结论血管元件存在于A. prolifera（Retz。）Copel植物体的整个血管连接中。和T. interrupta（Willd。）K. Iwats。注意到气管元件长度-宽度和血管端壁长度-宽度的种群间变化。到现在为止，据报道仅有七属蕨类植物存在血管，而这两个属是以前的新属。中度至高度扰动的地方，作为快速繁殖的种群，显示气管元件长度-宽度和血管端壁长度-宽度的种群间变化。结论血管元件存在于A. prolifera（Retz。）Copel植物体的整个血管连接中。和T. interrupta（Willd。）K. Iwats。注意到气管元件长度-宽度和血管端壁长度-宽度的种群间变化。到现在为止，据报道仅有七属蕨类植物存在血管，而这两个属是以前的新属。中度至高度扰动的地方，作为快速繁殖的种群，显示气管元件长度-宽度和血管端壁长度-宽度的种群间变化。结论血管元件存在于A. prolifera（Retz。）Copel植物体的整个血管连接中。和T. interrupta（Willd。）K. Iwats。注意到气管元件长度-宽度和血管端壁长度-宽度的种群间变化。到现在为止，据报道仅有七属蕨类植物存在血管，而这两个属是以前的新属。结论血管元件存在于A. prolifera（Retz。）Copel植物体的整个血管连接中。和T. interrupta（Willd。）K. Iwats。注意到气管元件长度-宽度和血管端壁长度-宽度的种群间变化。到现在为止，据报道仅有七属蕨类植物存在血管，而这两个属是以前的新属。结论血管元件存在于A. prolifera（Retz。）Copel植物体的整个血管连接中。和T. interrupta（Willd。）K. Iwats。注意到气管元件长度-宽度和血管端壁长度-宽度的种群间变化。到现在为止，据报道仅有七属蕨类植物存在血管，而这两个属是以前的新属。