西藏高原硬叶柳叶片结构对寒旱环境的适应机制
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引用本文:郭文文,卓么草,周尧治.西藏高原硬叶柳叶片结构对寒旱环境的适应机制[J].西北植物学报,2019,39(5):784~790
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郭文文1,卓么草2,周尧治1* (1 西藏农牧学院 高原生态研究所西藏林芝 8600002 西藏农牧学院 植物科学学院西藏林芝 860000) 
基金项目:国家重点研发计划(2017YFC0506801)
中文摘要:为探究硬叶柳叶片结构对高寒高海拔环境的适应机制,以西藏那曲嘉黎县硬叶柳叶片为试验材料,应用石蜡切片技术和植物显微技术,分析硬叶柳叶片结构对寒旱环境的适应特征。结果显示:(1)硬叶柳叶片为异面叶,叶片背面有表皮毛,叶片主叶脉在叶片下部凸起,呈现不规则半圆形;栅栏组织呈柱状紧密排列,有2~3层,海绵组织形状多为短柱状或者短球形,细胞间隙较大。(2)随着海拔的不断升高,硬叶柳叶片厚度从最低海拔(4 000 m)的40.4 μm增加到最高海拔(4 700 m)的68.04 μm,其中叶片下表皮厚度在海拔4 400 m~4 700 m之间呈显著增加的趋势,而上表皮厚度在4 000~4 400 m之间变化不显著;海绵组织和栅栏组织厚度变化分别在9.34~24.84 μm、25.63~40.36 μm之间,且随海拔梯度的升高海绵组织和栅栏组织的厚度均呈不显著的增加趋势。(3)硬叶柳叶片上表皮无气孔分布,下表皮散生着大量气孔,且气孔器小而密集,其密度为17.87~28.37个·mm-2,单位面积的气孔总周长为0.13~0.25 mm,但气孔密度和单位面积的气孔周长在海拔梯度上没有明显变化。研究表明,硬叶柳叶片主要通过增加叶片厚度来适应高海拔地区的寒旱环境。
中文关键词:硬叶柳  叶片  解剖结构  海拔梯度
 
The Salix sclerophylla Leaves to Adapt to the Cold and Drought Environment on the Tibetan Plateau
Abstract:In order to explore the adaptation mechanism of leaf structure of Salix sclerophylla to cold and high altitude environment, we used the leaf of S. sclerophylla in Jiali County, Naqu, Tibet as experimental material to study the adaptation characteristics of leaf structure of S. sclerophylla to cold and drought environment by paraffin section technology and plant microscopy technology. The results showed that: (1) the leaves of S. sclerophylla willow are heterophylous leaves with epidermis on the back of the leaves. The main veins of the leaves are convex in the lower part of the leaves, showing irregular semicircles. The palisade tissue is arranged in a column, with 2 to 3 layers. The shape of the sponge tissue is mostly short columnar or short spherical, and the cell gap is large. (2) With the increase of altitude, the leaf thickness of the S. sclerophylla willow increased from 40.4 μm at the lowest altitude (4 000 m) to 68.04 μm at the highest altitude (4 700 m). The thickness of the epidermis of the leaves increased significantly between 4 400 m and 4 700 m above sea level, but the thickness of the upper epidermis varies in not significant from 4 000 to 4400 m change. The thickness of sponge tissue and palisade tissue were between 9.34-24.84 μm and 25.63-40.36 μm, respectively. The thickness of sponge tissue and palisade tissue increased with altitude gradient, but change is not significant. (3) There is no stomatal distribution on the upper epidermis of the leaves of S. sclerophylla willow, and a large number of stomata are scattered in the lower epidermis. The stoma density is 17.87-28.37 No·mm-2, and the total stoma perimeter per unit area is 0.13-0.25 mm, but the stoma density and the total stoma perimeter per unit area have no significant change in the elevation gradient. Studies have shown that the leaves of S. sclerophylla willows mainly adapt to the cold and drought environment in high altitude areas by increasing the thickness of the leaves.
keywords:Salix sclerophylla  leaves  anatomical structure  altitude gradient
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