关键词: 水位变化, 叶片解剖结构性状, 生态适应, 禾本科, 莎草科

Abstract: Aims As a crucial organ for plants to conduct matter and energy exchange with the external environment, the leaf's anatomical structure changes can directly reflect the adaptation strategies of plants to diverse habitats. This study aims to conduct research on the dominant plants in different habitats of Dajiuhu wetland, Mt. Shennongjia, and investigate the adaptive response of plant leaf anatomical structure traits to habitats with different water levels. Methods We selected six different habitats (xeric meadow (HA), moderate- xeric meadow (HB), hygrophyte- mesophyte meadow (Z), degraded semi-hygrophyte marshes (SA), hygrophyte herbaceous marshes (SB), hygrophyte peat bogs (SC)) in Dajiuhu wetland in Shennongjia as the study area. Six herbaceous plants, including Carex argyi, Rhynchospora chinensis, Scirpus karuisawensis, Eragrostis pilosa, Calamagrostis pseudophragmites, Agrostis matsumurae were collected from the Dajiuhu wetland and the leaf anatomy of these species were studied by using paraffin sectioning method. Important findings The results showed that: (1) the adaptation structures of different plants to the changes in habitat water level differed. Carex argyi, Rhynchospora chinensis and Scirpus karuisawensis grew in swampy habitats with good water conditions. When the water level increased, the air cavity, vascular bundle and upper and lower epidermal cell cross-section significantly increased. The leaf thickness and xylem diameter in vascular bundles increased significantly in Carex argyi and Rhynchospora chinensis; (2) Eragrostis pilosa, Calamagrostis pseudophragmites and Agrostis matsumurae were distributed in drier dry and mesic meadows, and most structures in leaf transection did not show significant differences between habitats. Only the width and thickness of bulliform cells and upper epidermal cell thickness of Eragrostis pilosa, along with the lower epidermal cell thickness of Calamagrostis pseudophragmites, increased when the habitat water level decreased. Eragrostis pilosa and Agrostis matsumurae are C4 plants with trichomes or protuberances on the leaf surface, which may be related to the drought resistance. The developed aerenchyma and conducting tissues of Carex argyi, Rhynchospora chinensis and Scirpus karuisawensis ensured the flow of gas and water. The study of the anatomical structure traits of plant leaves in different habitats reflects the strategies of the wetland plants to cope with the changes in ground water level. It can provide a reference for exploring the adaptation of plants to environmental water changes.

Key words: water level change, leaf anatomical structure traits, ecological adaptation, Poaceae, Cyperaceae