关键词: 虉草, 解剖结构, 质外体屏障结构, 组织化学

Abstract: Reed canarygrass (Phalaris arundinacea) is a perennial herb adapted to wetland environments. The current work explores the anatomy and histochemistry of the adventitious roots, stems (rhizomes and culms), leaves and the permeability of apoplastic barriers of reed canarygrass. The anatomy and histochemistry of P. arundinacea were studied using an optical microscope and fluorescent microscope. Sections were stained with Sudan red 7B (SR7B) for suberin lamellae, with berberine hemisulfate-aniline blue (BAB) for casparian bands and lignified cell walls, phloroglucinol-HCl (Pg) for lignin and berberine hemisulfate-potassium thiocyanate for apoplastic permeability. Concentrated sulfuric acid digestion (AD) was used to detect the wavy casparian bands in young rhizomes and culms. The adventitious roots had a primary structure comprising epidermis, exodermis, cortex, endodermis and vascular cylinder with sclerenchyma; the stems comprised a cuticle, epidermis, peripheral mechanical ring, exodermis, cortex, endodermis, sclerenchyma ring with vascular bundles and pith cavity. The apoplastic barriers consisted of adventitious roots with a suberized and lignified endodermis and an exodermis, stems possessed a cuticle, suberized and lignified peripheral mechanical ring and a sclerenchyma ring, and rhizomes with endodermis and exodermis, culms only with exodermis. The air space consisted of pith cavities and cortical cavities in the stems, and aerenchyma in roots and leaves. This research revealed that reed canarygrass has the key constitutive, structural and histochemical features in roots and stems that allow it to grow in wetlands, be protected against oxygen leakage from aerenchyma, with-stand seasonal flooding and consequently, widely distributed. The anatomical structures and histochemical features of these perennial, rhizomatous grasses enhance our awareness of the biology of this species in native Asian and North American invaded habitats to select species for the restoration of degraded wetland of the Jianghan Floodplain and Three Gorges Reservoir Region of the Yangtze River.

Key words: Phalaris arundinacea, anatomy, apoplastic barriers, histochemistry