不同功能型原生荒漠植物对小降雨的光合响应  

Photosynthetic responses of different plant functional types to small rainfall events in a non-disturbed desert.

作　　者：吴玉[1,2,3] 郑新军[1,3] 李彦[1,3] 

机构地区：[1]中国科学院新疆生态与地理研究所,荒漠与绿洲生态国家重点实验室,乌鲁木齐830011 [2]中国科学院大学,北京100049 [3]中国科学院阜康荒漠生态系统研究站,新疆阜康831500

出　　处：《生态学杂志》2013年第10期2591-2597,共7页Chinese Journal of Ecology

基　　金：国家重点基础研究发展计划项目(2009CB825102);国家国际科技合作计划项目(2010DFA92720-05)资助

摘　　要：小降雨事件(≤5 mm)在干旱区年降雨频次中占很大比重,并且发生间隔较短。为揭示荒漠植物对小降雨的利用策略,在准噶尔盆地原始生境中研究了4种植物功能型(短生活史草本植物、长生活史草本植物、非潜水灌木和潜水灌木,共28物种)对1和6 mm人工降雨的光合响应。结果表明,1 mm降雨后,多数草本植物净光合速率(P_n)、气孔导度(g_s)上升,非潜水灌木的g_s和潜水灌木的瞬时水分利用效率(WUE)响应的幅度接近于6mm降雨效应。为探讨植物利用小降雨的可能机制,选取单位面积叶片吸水量(LWUC)和叶片相对含水量增量(R_w)对叶片进行吸水能力测试。结果表明,小降雨既可通过叶面毛被草本植物直接吸收利用,也可通过增加微生境湿度,调节气孔导度,降低蒸腾而使灌木间接获益。In arid areas, small rainfall （≤5 mm） events account for a large proportion of annual precipitation frequency, and occur in short time intervals. To elucidate the possible strategies of desert plants in utilizing small rainfall, this paper studied the photosynthetic responses of 28 plant species to simulated 1 and 6 mm rainfalls in Junggar Basin of Northwest China. For comparison, the 28 species were grouped into four plant functional types, i.e., herbaceous plants with short life cycle, herbaceous plants with long life cycle, nonphreatophyte shrubs, and phreatophyte shrubs. The results showed that after 1 mm rainfall, the net photosynthetic rate （Pn） and stomatal conductance （gs） of most herbaceous plants increased, while the gs of nonphreatophyte shrubs and the instantaneous water use efficiency （WUE） of phreatophyte shrubs had a response magnitude similar to that after 6 mm rainfall. In order to explore the possible mechanisms of small rainfall utilization, the leaf water uptake content （LWUC） and the percentage increase of leaf water content （Rw） were measured for assessing the leaf water uptake capacity of all the test species. The results revealed that most herbaceous plants with trichomes could directly absorb small rainfall, while shrubs could be indirectly benefited via increasing the humidity of microhabitat, regulating stomatal conductance, and reducing transpiration.

关 键 词：小降雨 植物功能型 叶面吸水 叶面毛 光合速率 气孔导度 

分 类 号：Q948[生物学—植物学]