毛乌素沙地两种典型灌木叶片凝结水吸收能力及吸水途径  

Foliar condensate absorption and its pathways of two typical shrub species in the Mu Us Desert

作　　者：桂子洋 秦树高[1,2] 胡朝 白凤 石慧书 张宇清[1,2] GUI Zi-Yang;QIN Shu-Gao;HU Zhao;BAI Feng;SHI Hui-Shu;ZHANG Yu-Qing(Yanchi Research Station,School of Soil and Water Conservation,Beijing Forestry University,Beijing 100083,China;Key Laboratory of National Forestry and Grassland Administration on Soil and Water Conservation,Beijing Forestry University,Beijing 100083,China;Ningxia Habahu National Nature Reserve Administration,Yanchi,Ningxia 751500,China)

机构地区：[1]北京林业大学水土保持学院宁夏盐池毛乌素沙地生态系统国家定位观测研究站,北京100083 [2]北京林业大学水土保持国家林业和草原局重点实验室,北京100083 [3]宁夏哈巴湖国家级自然保护区管理局,宁夏盐池751500

出　　处：《植物生态学报》2021年第6期583-593,共11页Chinese Journal of Plant Ecology

基　　金：国家自然科学基金(31700638)。

摘　　要：凝结水是半干旱地区生态系统重要的水源,已有研究表明,一些沙生植物可以通过叶片吸收凝结水以改善其水分状况。该研究以毛乌素沙地典型沙生灌木黑沙蒿(又称油蒿)(Artemisia ordosica)和北沙柳(Salix psammophila)为研究对象,研究这两种植物的叶片是否具有吸收凝结水的能力,并探究叶片吸水的途径及运移的通道。分别将黑沙蒿与北沙柳失水和未失水离体枝条置入人工模拟加湿室中,使用高丰度氘水标记的凝结水进行浸润实验,比对浸润前后枝条质量、叶片水及茎水氢同位素丰度变化,确定黑沙蒿和北沙柳的叶片吸水能力;并将盆栽黑沙蒿和北沙柳整株置入人工模拟加湿室,使用荧光标记的凝结水进行浸润实验,比对浸润前后叶片、小枝荧光显像,确定黑沙蒿和北沙柳叶片吸收和运移凝结水的途径。结果显示:(1)黑沙蒿和北沙柳未失水枝条在浸润前后质量无显著差异,黑沙蒿和北沙柳失水离体枝条在凝结水浸润后质量显著提高了2.04%和6.74%,叶片水氘丰度提高了170.10‰和104.09‰,茎水氘丰度提高了10.52‰和12.72‰;(2)荧光标记凝结水浸润后,荧光示踪剂分布在黑沙蒿和北沙柳叶片的角质层、气孔、海绵组织、栅栏组织和维管束中,黑沙蒿叶片的厚角组织中也发现了荧光示踪剂,两种灌木小枝的表皮、韧皮部、木质部和髓中均观察到荧光。以上结果表明,毛乌素沙地两种典型灌木叶片均具有吸收凝结水的能力,水分亏缺植株的吸水能力更强;两种灌木叶片通过气孔或角质层吸收凝结水,并通过叶肉运移至维管束乃至小枝。黑沙蒿与北沙柳叶片具有的吸水功能可能是其适应干旱期水分亏缺的重要水分利用策略。Aims Condensate is an important water source for plants in the ecosystems of drylands. Previous studies have found that some desert plants can absorb condensate via leaves. This study aimed to determine the capacity of the foliar condensate absorption of typical shrub species(Artemisia ordosica and Salix psammophila) in the Mu Us Desert, and to explore the pathways of foliar condensate absorption and transport. Methods The dehydrated and non-dehydrated detached shoots of A. ordosica and S. psammophila were placed in an artificial chamber and exposed to deuterium labelled condensate, and the foliar condensate absorption was determined by comparing the differences of shoot masses and isotopic signals between pre-and post-immersion. The potted whole plants of A. ordosica and S. psammophila were placed in an artificial chamber and exposed to fluorescent tracer solution, and the pathways of foliar water uptake and transport were determined by comparing the differences of fluorescent tracing in leaves and twigs between pre-and post-immersion. Important findings(1) After the deuterium labelled dew exposure, no significant differences were found in shoot masses between pre-and post-immersion of non-dehydrated detached shoots of A. ordosica and S. psammophila. However, the dehydrated shoot masses significantly increased by 2.04% and 6.74% in A. ordosica and S. psammophila, respectively;the δD(stable isotope ratio of hydrogen) of leaf water increased by 170.10‰ and 104.09‰ in A. ordosica and S. psammophila, respectively;and the δD of xylem water increased by 10.52‰ and 12.72‰ in A. ordosica and S. psammophila, respectively.(2) After the fluorescent tracer solution exposure, fluorescence was observed in the cuticles, stomata, spongy mesophyll, palisade cells and vascular bundle of the leaves of A. ordosica and S. psammophila. The fluorescence was also found in collenchyma of the leaves of A. ordosica. In addition, the fluorescence was observed in phloem, xylem, and pith of twigs of two shrub species. This study fo

关 键 词：黑沙蒿 北沙柳 叶片吸水 凝结水 水分利用策略 

分 类 号：Q948[生物学—植物学]