菰适应湿地环境的解剖和屏障结构特征研究

菰(Zizania latifolia)是一种多年生挺水植物,为了探讨该植物根、茎和叶的解剖结构、组织化学及其质外体屏障的通透性生理。该文利用光学显微镜和荧光显微镜,对菰的根、茎、叶进行了解剖学和组织化学研究。结果表明:(1)菰不定根解剖结构由外而内分别为表皮、外皮层、单层细胞的厚壁机械组织层、皮层、内皮层和维管柱;茎结构由外而内分别为角质层、表皮、周缘厚壁机械组织层、皮层、具维管束的厚壁组织层和髓腔。叶鞘具有表皮和具维管束皮层,叶片具有表皮,叶肉和维管束。(2)不定根具有位于内侧的内皮层及其邻近栓质化细胞和外侧的外皮层组成的屏障结构;茎具内侧厚壁机械组织层,外侧的角质层和周缘厚壁机械组织层组成的屏障结构,屏障结构的细胞壁具凯氏带、木栓质和木质素沉积的组织化学特点,叶表面具有角质层。(3)菰通气组织包括根中通气组织,茎、叶皮层的通气组织和髓腔。(4)菰的屏障结构和解剖结构是其适应湿地环境的重要特征,但其茎周缘厚壁层和厚壁组织层较薄。由此推测,菰适应湿地环境,但在旱生环境中分布有一定的局限性。

Anatomy and apoplastic barrier histochemistry characteristics of Zizania latifolia adapted to wetland environment

Wild rice(Zizania latifolia)is a famous, perennial, emergent vegetable in China. The current work explores the anatomy and histochemistry of roots, stems and leaves and the permeability of apoplastic barriers of wild rice. The anatomy and histochemistry of Z. latifolia were studied by optical microscope and fluorescence microscope. Sections were stained with Sudan red 7B for suberin lamellae, berberine hemisulfate-aniline blue for Casparian bands and lignified walls, and phloroglucinol-HCl(Pg)for lignin. The results were as follows:(1)The adventitious roots in wild rice suberized and lignified endodermis and adjacent, thick-walled cortical layers and suberized and lignified hypodermis, composed of a uniseriate sclerenchyma layer underlying uniseriate exodermis; The stems of wild plants included stolons, rhizomes, and culm. Rhizomes, stolons, and culms had two rings of thickened, lignified cells, the peripheral mechanical ring and the sclerenchyma ring; The latter delimits the cortex from the CC(central cylinder)and was usually associated with vascular bundles; Stems had thick epidermal cuticle, a narrow peripheral mechanical ring, cortex, sclerenchyma ring with vascular bundles and pith cavity from the outside and inside. Leaf sheaths had epidermis and cortex with vascular bundles, and leaf blades had epidermis, mesophyll and vascular bundles.(2)Apoplastic barriers were found in roots and stems. The apoplastic barriers consist of that adventitious roots had endodermis, adjacent suberized cells and exodermis; Stems have cuticle, suberized and lignified peripheral mechanical ring and sclerenchyma ring, and the cell wall of apoplastic barriers had Casparian band, lignin and suberin. Leaves had cuticles at surface.(3)The air space consist of aerenchyma in roots, and pith cavities and aerenchyma in stems and leaves.(4)The peripheral mechanical ring and sclerenchyma ring were thinner in wild rice stems that adapt to wetland environment, but limited distribution to drought environment.