荷叶铁线蕨孢子体解剖结构和组织化学特征研究

Anatomical structure and histochemical features of Adiantum reniforme var. sinense sporophyte(Pteridaceae)

关键词:  内皮层, 网状中柱, 厚壁组织层, 栓质层, 薄角质层

Key words:  endodermis, dictyostele, sclerenchyma layer, suberin lamellae, thin cuticle

摘要:

荷叶铁线蕨为岩生珍稀蕨类植物,分布在中国重庆市万州、涪陵等极少地区。为揭示荷叶铁线蕨生长特性,采集栽培在种质资源圃中的荷叶铁线蕨根样、根状茎、在阳光下生长和在阴暗环境下生长的叶片,固定于甲醛-酒精-乙酸溶液中,用双面刀片进行徒手切片,分别用三种0.1%苏丹红、0.1%硫酸氢黄连素-苯胺兰、0.05%甲苯胺蓝染色剂染色,之后在莱卡光学显微镜、荧光显微镜下观察,研究荷叶铁线蕨适应生长的环境解剖学和组织化学特征。结果表明:(1)荷叶铁线蕨孢子体具初生结构,不定根内皮层具凯氏带和栓质化,厚壁组织层,皮层和表皮。(2)茎具网状中柱,内皮层具凯氏带且栓质化,厚壁组织层,皮层和薄的角质层。(3)叶具内皮层包围维管束,周缘厚壁组织层,等面叶,木质化表皮和薄角质层。(4)该植物的网状中柱、内皮层、厚壁组织层和木质化表皮等结构表明荷叶铁线蕨适应旱生环境,而其薄的角质层和等面叶则表明该植物适应阴生环境。因此,荷叶铁线蕨的解剖特征表明其适应阴生、干旱的岩生环境。

Abstract:

The distribution of the rare perennial fern Adiantum reniforme var. sinense(Pteridaceae)which is endemic to shady cliff environments is limited to small areas of Wanzhou and Fuling, Chongqing, China. In order to reveal the growth characteristics of A. reniforme var. sinense in the germplasm resource nursery,we observed the tissue structure of A. reniforme var. sinense, which including in the roots, rhizomes, leaves grown in the sun and in shade. First of all, the roots, rhizomes, leaves were collected and fixed in formaldehyde-alcohol-acetic acid solution, and we cut the tissue structure of the plant with a double-sided blade to make freehand sections, then the tissue were stained with three kinds of 0.1% Sudan red, 0.1% berberine bisulfate-aniline blue, and 0.05% toluidine blue, at last plant tissue sections were observed under the Lycra optical microscope and the fluorescence microscope. In this study, we used brightfield and epifluorescence microscopy to investigate the anatomical structures and histochemical features that may allow this species to thrive in shady, dry cliff environments. The results were as follows:(1)The A. reniforme var. sinense sporophyte had a primary structure, the roots had an endodermis with Casparian walls, suberin lamellae, a thickened sclerenchyma layer around the endodermis, a cortex, and a rhizodermis.(2)The stems had a dictyostele, an endodermis with Casparian walls and suberin lamellae, a thickened sclerenchyma layer around the endodermis, a cortex, and a thin cuticle.(3)The leaves had an endodermis surrounded the vascular bundles, a peripheral sclerenchyma layer, an isolateral mesophyll, a lignified epidermis and a thin cuticle.(4)The dictyostele, endodermis, sclerenchyma layers, and lignified epidermal walls reflected the drought tolerance of A. reniforme var. sinense, while its thin cuticle and isolateral mesophyll suggested tolerance of shady environments. Thus, according to the anatomical characteristics of A. reniforme var. sinense, it is concluded that A. reniforme var. sinense are consistent with adaptations to shady, dry cliff environments.