青藏苔草叶片解剖结构对生境干旱化的响应

Response of Carex moorcroftii leaf anatomical structure to habitat aridification

关键词:  青藏苔草, 叶片, 解剖结构, 土壤体积含水率, 生境干旱化

Key words:  Carex moorcroftii, leaf, anatomical structure, soil volumetric moisture content, habitat aridification

摘要:

叶片是暴露在外界环境条件下最大且可塑性较敏感的营养器官。为探讨生境干旱化对湿地植物叶片解剖结构的影响,该文以青藏苔草(Carex moorcroftii)叶片为研究对象,沿生境干旱化梯度设置样地,并分析了青藏苔草叶片解剖结构对生境干旱化的响应。结果表明:(1)叶尖和叶基部位远轴面的表皮细胞、泡状细胞和气腔面积,以及叶基部位的叶片厚度和机械组织厚度均与土壤体积含水率呈显著正相关(R²=0.06～0.34, P<0.01); 叶尖、叶中和叶基部位近轴面角质层厚度、细胞面积、维管束数量,叶中部位维管束直径均与土壤体积含水率呈显著负相关(R² = 0.08～0.53, P<0.01)。(2)青藏苔草叶片解剖结构具有较大的可塑性(0.53～0.94)和变异性(18%～63%),泡状细胞、气腔、近轴面表皮细胞的可塑性和变异性最大,叶基解剖结构可塑性指数与变异系数显著高于叶尖和叶中部位(P<0.05)。当生境干旱化时,青藏苔草叶片近轴面角质层加厚、表皮细胞面积增大、气腔面积减小、分化出泡状细胞等特征适应干旱生境,主要采取保护型和节约型策略适应干旱生境。该研究结果有助于揭示青藏苔草叶片解剖结构应对干旱生境的响应策略,为高寒草甸的保护和植被恢复提供理论参考。

Abstract:

Leaves are the largest and more sensitive vegetative organs exposed to external environmental conditions. In order to investigate the effects of habitat aridification on the leaf anatomical structure of wetland plants, Carex moorcroftii leaf plots were set up along the gradient of habitat aridification, and the response of leaf anatomical structure to habitat aridification was analyzed in this study. The results were as follows:(1)The epidermal cells, bulliform cells and air cavity area on the abaxial surface of leaf tip and leaf base, leaf thickness and mechanical tissue thickness at leaf base were significantly positively correlated with soil volumetric moisture content(R²=0.06-0.34, P<0.01); the paraxial cuticle thickness, cell area, number of vascular bundles in parts of leaf tip, leaf middle and leaf base, and diameter of vascular bundle in leaf middle were significantly negatively correlated with soil volumetric moisture content(R²=0.08-0.53, P<0.01).(2)The anatomical structure of C. moorcroftii leaf had great plasticity(0.53-0.94)and variability(18%-63%), and bulliform cells, air cavities, and paraxial epidermal cells had the greatest plasticity and variability, and the plasticity index and the coefficient of variation of leaf base anatomical structure were significantly higher than that of leaf tip and leaf middle(P<0.05). When the habitat was aridified, C. moorcroftii leaf adapt to the arid habitat by thickening the cuticle on the paraxial surface, increasing the epidermal cell area, decreasing the air cavity area, and differentiating middle cells, and mainly adopted protective and frugal strategies to adapt to the arid habitat. The results of this study are helpful to reveal the response strategies of C. moorcroftii leaf anatomical structure to arid habitat, and provide theoretical reference for protection and vegetation restoration of alpine meadow.