【作者】 张友焱；

【导师】 孙保平； 周泽福；

【作者基本信息】 北京林业大学 ， 水土保持与荒漠化防治， 2006， 博士

【摘要】 植物水分生理特性的研究一直是植被建设中的热点和难点问题,其有利于了解植物的生长机制以及环境对其作用,为植被建设服务。本文以毛乌素沙地几种主要灌木和乔木为研究对象,研究了不同植被下土壤水分的动态变化,开展了5种灌木的水分生理特性(光合、蒸腾特性、水分利用效率、水势变化规律、耐旱特性、灌木对干旱和CO2浓度升高的响应)的试验研究,比较分析了5种灌木生理因子的变化规律以及5种灌木对环境的适应方式,为该区灌木的种植和配置提供了一定的依据。另外,以热扩散技术为手段,研究了乔木的耗水特性,并以降水量和乔木的耗水量为依据,对乔木的水分供求关系进行了探讨,提出了该区乔木栽植应注意的密度问题。其得出主要结论如下:〔1〕在主要生长期(4-9月),樟子松、新疆杨、旱柳耗水量分别为1140.0、883.49、2204.8 mm。对3种乔木的耗水量和降水量进行水分平衡分析,结果表明:同期降水总量只能满足樟子松蒸腾耗水量的28.1 %、新疆杨的36.3 %、旱柳的14.5 %,现种植密度下乔木以利用地下水/土壤水为主,为合理利用水资源,该地区3种乔木的种植应加大株行距。〔2〕5种灌木的光合能力最大多出现在6月或7月,年均光合能力大小顺序为羊柴〉柠条〉油蒿〉紫穗槐〉沙地柏;年均蒸腾速率大小顺序依次为羊柴〉油蒿〉柠条〉紫穗槐〉沙地柏;其年均水分利用效率大小顺序为沙地柏〉紫穗槐〉柠条〉油蒿〉羊柴。5种灌木水分利用效率最大出现在6:00或8:00。〔3〕5种灌木枝条水势日变化呈早晚高、中间低,其月际变化呈现两端月份低,中间高的趋势,与降水形成对应关系,其中6月水势最低,8月最高。5个灌木年均水势由低到高依次为沙地柏、柠条、油蒿、羊柴、紫穗槐。枝条水势与蒸腾速率存在明显的负相关关系,在一般情况下,枝条水势的降低能降低植物的水分利用效率,但对各植物的影响不一样。〔4〕干旱胁迫降低灌木光合速率和蒸腾速率,但能在一定程度上改善水分利用效率,并影响其峰值的大小及出现时间。随着干旱胁迫的增加,5种灌木黎明前水势、峰值、日均水势都减小(绝对值增加)。5种灌木中沙地柏、柠条主要通过渗透调节来保持膨压以适应干旱胁迫,而紫穗槐、油蒿与羊柴主要通过组织弹性来保持更多还原

【Abstract】 Study on water physiological characters of plant is one of the most important and difficult problems for vegetation construction. It is advatageous to understand the plant’s growth mechanism and the environment influence on plants. This paper takes several kinds of arbuscles and tall trees as research material, and the water physiological charaters of 5 kinds of shrubs and water consumption characters of 3 kinds of trees are studied. Base on these studies, varity of physiological factors are contrasted among 5 kinds of arbuscles and the methods that shrubs adapt to environment are analyzed. In addition, base on the water consumption and precipitation, the water balance and characters of water consumptionof tall trees are analysed.The main conclusions are drawed to be as follows.〔1〕In the main growth season, the water consumption of 3 kinds of trees(Pinus sylvestris var. mongolica, Populus alba.var. pyramidalis, Salix matsudana) are 1140.0, 883.49 and 2204.8mm.The results of water balance analysis were that the rainfall meet the requirement of 28.1% of water consumption of Pinus sylvestris var. mongolica, 36.3% of Populus alba.var. pyramidalis, and 14.5% of Salix matsudana. The consumpted water mainly was ground water or soil water. To utilize the water resource reasonly, the row spacing should be wider.〔2〕The time when the maximal photosynthetic ability occurred was in July or June, and the sequence of annual average photosynthetic ability arranged from big to small was Hedysarum mongolicum, Caragana intemedia, Artemisia ordosica, Amorpha fruticosa and Sabina vulgaris, and the sequence of annual average transpiration rate was Hedysarum mongolicum, Artemisia ordosica, Caragana intemedia, Amorpha fruticosa, Sabina vulgaris, and sequence of the annual average value of WUE was Sabina vulgaris, Amorpha fruticosa, Caragana intemedia, Artemisia ordosica,Hedysarum mongolicum. The time when maximal WUE occurred was on 6:00 or 8:00.〔3〕The daily varity of water potential of 5 kinds shrubs obeyed the rule that water potential in morning and evening was high and in midday was low, and the monthly varity also obeyed the更多还原