【作者】 何炎红；

【导师】 郭连生；

【作者基本信息】 内蒙古农业大学 ， 水土保持与荒漠化防治， 2006， 博士

【摘要】 本文从2003-2005年对乌兰布和沙漠东北部主要植物种生理生态特征、植被特征和水分平衡等进行了研究,进而探讨了植物与水资源的关系,主要结果如下:（1）对该区土壤容重、田间持水量等土壤物理性质测定研究指出,土壤在垂直深度20cm以下空间异质性较小;沙土饱和导水率（12.85cm/h）大于粘土（0.43cm/h）;土壤水势、土壤蒸发水分传输阻力与土壤体积含水量的关系均呈y=ax^-b。固定沙地、半固定沙地、流动沙地植被盖度分别为33.1,24.0和6.3%,白刺、沙冬青、油蒿和梭梭盖度占植被盖度80%以上,其根系主要分布在60cm以上,白刺、油蒿根系生物量与总生物量之比大于沙冬青和梭梭。该区水资源贫乏,植物可利用的水资源主要是自然降水和土壤中储存的水分。降水的入渗深度小于80cm,储水量与土层深度的关系曲线有直线型、指数型、“S”型和幂函数型。正常环境条件下,土壤含水量、生物量和叶面积指数等在年度间变化较小。（2）树木光合速率、蒸腾速率、气孔导度等生理指标与光照强度、叶水势的关系都呈y=a+b(1-e^-kx)（其中y为生理指标,x为光强度或叶水势）。白刺光合速率水势补偿点（-4.07MPa）大于沙冬青（-4.44MPa）;最大净光合速率(μmolm^-2s^-1)白刺（9.45）>梭梭（6.38）>油蒿（5.29）>沙冬青（4.06）;最大蒸腾速率(mmolm^-2s^-1)沙冬青（6.76）>白刺（4.43）>梭梭（2.40）>油蒿（1.82）;最大气孔导度(molm^-2s^-1)白刺（0.15）>沙冬青（0.13）>梭梭（0.11）>油蒿（0.08）。光合速率、蒸腾速率日平均值白刺>梭梭>沙冬青>油蒿;气孔导度日平均值白刺>沙冬青>梭梭>油蒿。（3）依据乌兰布和沙漠环境特点和树木生理生态特征建立了乌兰布和沙漠水分平衡模型,运用该模型对2000—2005年试验地水分平衡特征研究指出,降雨基本能满足水分消耗,随着叶面积指数的增加,土壤含水量降低,水分利用效率增加。流动沙地、半固定沙地和梭梭林土壤蒸发占降水的比例大于60%,固定沙地为44.8%。（4）根据试验地水分平衡特点对土壤水分植被承载力的研究指出,植物潜在水分消耗和水分利用效率可作为选择树种的依据;叶面积指数可作为评价土壤水分植被承载力的指标和调控植被结构的依据,叶面积指数愈大,土壤水分植被承载力愈大。该区最大叶面积指数粘土为1.7m²/m²,沙土为0.015m²/m²。更多还原

【Abstract】 In the present essay the relationship between the plants and water resource was studied based on the characteristics of the main plant physiological ecology, vegetation and water equilibrium in the northeast of Ulan Buh desert in 2003-2005. The main results were as follows:（1） The research indicated that the soil space heterogeneity was less below 20 cm in the soil depth by measuring bulk density of soil and the field capacity, that the saturated hydraulic conductivity of sandy soil （12.85cm/h） was greater than clay （0.43cm/h）, and that the relationship between soil water potential and water volume content, and that between the conduct resistance of the soil evaporation and water volume content could be both shown in the equation y=ax^–b.The vegetation coverage of fixed dune, semi-fixed dune and shifting dune was 33.1%,24% and 6.3% separately. The coverage of Nitraria tangutorum, Ammopiptanthus mongolicus,Artemisia ordosica and Haloxylon ammodendron was more than 80% of vegetation coverage. The rootage of the four plants was distributed above 60cm in soil depth, the rootage biomass in proportion to the total biomass of Nitraria tangutorum and Artemisia ordosica were more than that of Ammopiptanthus mongolicus and Haloxylon ammodendron.In the tested area the water resource was poor and it could mainly be used by the plant from rainfall and soil water. The infilatration depth of rainfall was less than 80cm. The relationship between the soil water storage and soil depth was linear, exponent,“s”function and power function. The annual change of soil water content, biomass and leaf area index was less in normal environment condition.（2） The relationships between plant photosynthetic rate, transpiration rate, stomatal conductance, and other physiology indexes and light intensity or water potential could be expressed by the equation y=a+b(1-e^-kx) （y stood for physiology index, x stood for light intensity or water potential）. The water potential compensation point （MPa） of net photosynthetic rate of Nitraria tangutorum （-4.07） was more than that of Ammopiptanthus mongolicus （-4.44）. The maximum net photosynthetic rate (μmolm^-2s^-1) is Nitraria tangutorum（9.45）>Haloxylon ammodendron（6.38）>Artemisia ordosica（5.29）>Ammopiptanthus mongolicus（4.06）; the maximum transpiration rate (mmolm^-2s^-1) Ammopiptanthus mongolicus （6.76） > Nitraria tangutorum （4.43） > Haloxylon更多还原