内蒙古西鄂尔多斯荒漠珍稀濒危植物水分利用策略

发布时间：2018-05-18 05:48

本文选题：稳定同位素 + 珍稀濒危植物　；参考：《中国林业科学研究院》2016年博士论文

【摘要】：水是干旱和半干旱地区生态系统过程和功能最重要的限制因子,它对植物生长发育、生存和分布起到关键作用。中国内蒙古西鄂尔多斯荒漠分布着四合木(Tetraena mongolica)、沙冬青(Ammopiptanthus mongolicus)、绵刺(Potaninia mongolica)、半日花(Helianthemum songaricum)等古地中海孑遗植物。这4种珍稀濒危植物的水分利用策略是植物长期适应进化形成的,而植物对气候变化(特别是降水格局变化)的响应受到其自身水分利用策略的影响。因此,研究这4种珍稀濒危植物的水分利用策略对于保护西鄂尔多斯古地中海孑遗植物、维护该地区物种多样性、维持区域生态系统平衡等具有重要的理论和实践意义。本研究以西鄂尔多斯荒漠珍稀濒危植物四合木、沙冬青、绵刺、半日花及其非濒危植物霸王(Sarcozygium xanthoxylum)为研究对象,利用氢、氧、碳稳定同位素技术,结合植物群落结构、土壤结构和植物生理生态学特征和环境因子(降水量、温度等)及多元线性混合模型等手段,分析判定了这5种植物的水分来源,定量阐明了这5种植物在不同降水条件下的植物水分利用率和水分利用效率,阐明其水分利用策略。得出主要结论如下:西鄂尔多斯地区夏季大气降水线方程(LMWL)为δD=7.287δ18O+1.170(R2=0.937,n=38);降水量效应显著,温度效应不显著;夏季降水受西风气团、局地蒸发气团以及东南和西南季风气团的影响。西鄂尔多斯荒漠土壤水主要来源于大气降水与地下水。小雨(0 mm降水量≤10mm)影响0~10 cm土壤含水量和土壤水δD值,对表层土壤(0~10 cm)的贡献率在30%以上;中雨(10 mm降水量≤20 mm)影响0~40 cm的土壤含水量和土壤水δD值;大雨(20 mm降水量≤30 mm)和特大暴雨(30 mm)影响0~100 cm的土壤含水量和土壤水δD值,降水对100~150 cm深层土壤水影响不显著。在土壤剖面中,0~10 cm表层土壤水受降水的直接影响明显,随着土壤深度增加,影响逐渐减小,贡献率逐渐降低;40 cm以下深层土壤水δD变化较小,趋于稳定。在西鄂尔多斯荒漠,小雨时,降水入渗具有自上而下活塞式下渗的特征;随着降水量的增大,降水以优先流的形式入渗,补给更深层土壤水分或浅层地下水。四合木、沙冬青、霸王植物水分主要来源于降水与80~150 cm深层土壤水,而绵刺、半日花主要依赖于降水。小雨(0 mm降水量≤10 mm)时,四合木、霸王和沙冬青主要利用深层土壤水;降雨量越大,这3种植物倾向于利用由降水补给的上层土壤水(0~40 cm)。植物对不同强度降水的利用率的大小顺序依次为:绵刺半日花沙冬青四合木、霸王。降水强度越大,植物对降水的利用率越高,越有利于四合木、沙冬青、霸王、绵刺和半日花植物的生长。小雨时,四合木、沙冬青和霸王有竞争土壤水分的现象。沙冬青、四合木、霸王、绵刺和半日花植物叶片δ13C平均值的大小顺序依次为沙冬青(-23.3‰)四合木(-25.2‰)霸王(-25.8‰)绵刺(-26.6‰)半日花(-26.8‰)。这五种植物的水分利用效率平均值的高低顺序依次为沙冬青(5.4 mmol CO2·mol-1 H2O)四合木(4.8 mmol CO2·mol-1 H2O)霸王(4.6 mmol CO2·mol-1 H2O)绵刺(4.3 mmol CO2·mol-1 H2O)半日花(4.2 mmol CO2·mol-1 H2O)。光合速率的高低顺序依次为绵刺半日花霸王四合木沙冬青。四合木、沙冬青、霸王、绵刺叶片光合速率日变化具有单峰、双峰两种类型;半日花叶片光合速率同时存在单峰、双峰和三峰曲线类型。蒸腾速率的高低顺序依次为绵刺半日花霸王,四合木沙冬青。沙冬青、四合木、绵刺和霸王的蒸腾速率日变化具有单峰和双峰两种类型;半日花叶片蒸腾速率日变化呈单峰型。深根植物沙冬青、霸王和四合木具有低光合、低蒸腾、高水分利用效率特点,为耐旱型水分利用策略;而浅根绵刺和半日花具有高光合、高蒸腾、低水分利用效率的特点,为避旱型水分利用策略。濒危植物四合木比同科非濒危植物霸王的水分利用效率稍高,但光合速率较低、蒸腾速率相似,可见,四合木仍具有较强的生存适应能力。濒危植物四合木和同科非濒危植物霸王的水分利用策略相似,二者共存有竞争土壤水分现象。建议在日后进行西鄂尔多斯荒漠地区植被恢复时,应尽量避免同时种植四合木和霸王。土壤蒸发水、土壤水和植物水受到强烈的蒸发作用而在当地大气降水线之下。植物水除了来源于大气降水外,主要还来自土壤水中的混合水。地下水氢氧稳定同位素值变化幅度小,较稳定,主要来自于当地降水的补充,几乎没有受到蒸发分馏作用的影响,其补给机制主要有两种:一是降水通过土壤缓慢渗入地下水,二是降水以“优先流”形式入渗到地下水。
[Abstract]:Water is the most important limiting factor for the process and function of the ecosystem in arid and semi-arid areas. It plays a key role in the growth, development, survival and distribution of plants. The Western Ordos desert in Inner Mongolia, Inner Mongolia, is distributed in the desert (Tetraena mongolica), Ammopiptanthus mongolicus, Potaninia mongolica, and semidiurnal flowers (Helianth). Emum songaricum) and other paleo Mediterranean relict plants. The water use strategy of these 4 rare and endangered plants is the long-term adaptive evolution of plants, and the response of plants to climate change (especially the change of precipitation pattern) is influenced by its own water use strategies. Therefore, the water use strategy of these 4 RARE and endangered plants is studied. It is of great theoretical and practical significance to preserve the species diversity and maintain regional ecosystem balance in the Western Ordos palaeo Mediterranean species, maintaining the species diversity and maintaining the regional ecosystem balance. This study is based on the study of four wood, holly, spines, semidiurnal flowers and the non endangered plant overlord (Sarcozygium Xanthoxylum) of the West Ordos For example, using hydrogen, oxygen, carbon stable isotope technology, combined with plant community structure, soil structure and plant physiological and ecological characteristics and environmental factors (precipitation, temperature, etc.) and multiple linear mixed models, the water sources of these 5 plants were analyzed and determined, and the water benefits of these 5 plants under different precipitation conditions were quantified. The main conclusions are as follows: the summer atmospheric water line equation (LMWL) in Western Ordos region is delta D=7.287 Delta 18O+1.170 (R2=0.937, n=38), the effect of precipitation is significant and the temperature effect is not significant; in summer, the precipitation is affected by the western wind mass, the local evaporation mass and the southeast and southwest monsoon air masses. The desert soil water in Western Ordos mainly comes from atmospheric precipitation and groundwater. Small rain (0 mm precipitation is less than 10mm) affects 0~10 cm soil water content and soil water delta D value, the contribution rate to surface soil (0~10 cm) is above 30%; rain (10 mm precipitation is less than 20 mm) affects 0~40 cm soil moisture and soil water delta D value; heavy rain (20 drops) Water content less than 30 mm) and heavy rainstorm (30 mm) affect the soil water content and soil water delta D value of 0~100 cm, and the influence of precipitation on 100~150 cm deep soil water is not significant. In soil profile, the direct influence of 0~10 cm surface soil water is directly affected by precipitation, with the increase of soil depth, the influence gradually decreases and the contribution rate decreases gradually; the deep soil below 40 cm is below the soil depth. The water delta D changes little and tends to be stable. In the West Ordos desert, the precipitation infiltration has the characteristics of top-down piston infiltration, and with the increase of precipitation, the precipitation is infiltrated in the form of preferential flow, recharging deeper soil moisture or shallow groundwater. Four wood, holly, and rewang plant water are mainly derived from precipitation and 80~150 cm. Deep soil water, while spiny, and semidiurnal flowers mainly depend on precipitation. When small rain (0 mm precipitation is less than 10 mm), four wood, overlord and sand Holly mainly use deep soil water; the greater the rainfall, the 3 plants tend to use the upper soil water supplied by precipitation (0~40 cm). The order of plant utilization rate of different intensity precipitation is in turn as follows: The greater the precipitation intensity, the higher the rainfall intensity, the higher the rainfall intensity, the more beneficial to the growth of four wood, holly, Overlord, spines and semidiurnal flowers. The four wood, the four wood, the four wood, the overlord, the spiny, and the leaves of the semidiurnal plant Delta 13C. The order of the average value is in order of -23.3 per 1000 (-23.3 per thousand) wood (-25.2 per thousand) overlord (-25.8 per thousand) spiny (-26.6 per thousand) semidiurnal flowers (-26.8 per thousand). The order of the average value of water use efficiency of the five plants is in order of the 5.4 mmol CO2. Mol-1 H2O (4.8 mmol CO2, mol-1). (4. 4.6 .3 mmol CO2. Mol-1 H2O) semidiurnal flowers (4.2 mmol CO2. Mol-1 H2O). The order of photosynthetic rate is in order of the four combined wood sand holly. The diurnal variation of photosynthesis rate of four wood, holly, tyrannosus and spiny leaves is single peak, two types in Shuangfeng; the photosynthetic rate of semidiurnal floral leaves is simultaneously single peak, Shuangfeng and three peak curve types The order of transpiration rate is as follows: the order of the transpiration rate in turn is the spiny semidiurnal flower overlord. The diurnal variation of transpiration rate of four wood holly, four wood, spines and tyrannosus has two types of single peak and Shuangfeng; the diurnal variation of the transpiration rate of the leaves of the semidiurnal flower leaves is single peak. The deep root plant, ASP, and four wood are low photosynthetic, low transpiration and high water content. With the characteristics of efficiency, it is a drought resistant water use strategy, while shallow root spines and semidiurnal flowers are characterized by high photosynthesis, high transpiration and low water use efficiency. It is a drought resistant water use strategy. The four wood ratio of endangered plants is slightly higher than that of the endangered plant of the non endangered plant, but the photosynthetic rate is low, the transpiration rate is similar, and four wood trees are visible. The four species of endangered plants are similar to the water use strategy of the endangered plants of the endangered plants, and the two coexist in the competitive soil water. It is suggested that when the vegetation restoration in the West Ordos desert area is restored, it is necessary to avoid the planting of four wood and Overlord at the same time. Soil water, soil water and planting should be avoided at the same time. The water is strongly evaporated and is under the local atmospheric water line. Plant water is mainly derived from the precipitation in the atmosphere, mainly from the mixed water in the soil water. The change of the stable isotope value of the hydrogen oxygen stable isotope is small and stable, mainly from the supplement of local precipitation, which is not influenced by the evaporation and fractionation, and its recharge There are mainly two mechanisms: first, precipitation is slowly infiltrating into groundwater through soil, and two is precipitation in the form of preferential flow into groundwater.
【学位授予单位】：中国林业科学研究院
【学位级别】：博士
【学位授予年份】：2016
【分类号】：Q948

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