Abstract: To explore the responses of leaf epidermal characteristic,anatomical structure and photosynthetic characteristics of Poa pratensis to drought stress,six materials of P. pratensis were selected in our study,of which include three introduced varieties from the United States:'Blue Ghost' 'Comet' and 'Martha',two native wild populations from Yingxian and Hunyuan in Shanxi,and the 'Taihang' P. pratensis variety bred in our laboratory. Weighing method was used to control the subsequent evapotranspiration rate (ET),and two different water gradients (W1:60% ET,W2:100% ET) were set,the leaves of six materials were taken and sliced by free-hand sectioning and paraffin sectioning to observe the epidermal characteristics and leaf anatomical structure under optical microscope,and the photosynthetic characteristics of these materials were measured. The results showed that the anatomical structure of most P. pratensis materials under W1 treatment were significantly lower than those under W2 treatment,while there was no significant difference in the ratio of length to width of stomas in the both upper and lower epidermis of each material between W1 and W2 treatments. The intercellular CO₂ concentration of 'Blue Ghost' was the highest,which was 57.23% higher than that of the smallest Yingxian. Correlation analysis showed that net photosynthetic rate was significantly positively correlated with the leaf anatomical structure parameters and photosynthetic characteristics parameters. Drought stress caused the leaf of P. pratensis become thinner,the vascular bundle area decreased,and the photosynthetic efficiency of P. pratensis was decreased as well.

Key words: P. pratensis, Drought stress, Epidermis characteristic, Anatomical structure, Photosynthetic characteristics

摘要： 为探究草地早熟禾(Poa pratensis)叶片表皮特征、解剖结构及光合特性对干旱胁迫的响应特点,试验选用6份草地早熟禾材料,包括美国引进品种:'Blue Ghost''Comet'和'Martha',山西野生居群:应县和浑源,以及自主选育的'太行'草地早熟禾品种,称重法控制后续蒸散量(Evapotranspiration rate,ET),设置2种水分梯度W1:60% ET,W2:100% ET处理,利用徒手切片法和石蜡切片法,在光学显微镜下观测草地早熟禾叶片的表皮特征和解剖结构,并测定其光合作用参数。结果表明:W1处理下,草地早熟禾叶片的解剖结构特征参数显著低于W2处理,而上下表皮气孔长宽比与W2处理无显著差异;'Blue Ghost'的胞间CO₂浓度最大,比最小的应县高出57.23%。相关性分析得出:净光合速率与叶片解剖结构特征参数和光合特征参数显著正相关;干旱胁迫促使草地早熟禾叶片变薄,维管束面积减小,草地早熟禾的光合效率降低。

关键词: 草地早熟禾, 干旱胁迫, 表皮特征, 解剖结构, 光合特性