【作者】 张卫宾；

【导师】 刘彤；

【作者基本信息】 石河子大学 ， 植物学， 2011， 硕士

【摘要】 水分是干旱区植被生长的主要限制因子,因此干旱区植被对降雨利用的有效性就显的至关重要。梭梭与白梭梭是古尔班通古特沙漠的建群种,因此研究两个物种的用水机制,对于在当前环境变化的背景下预测其种群发展趋势,提出科学合理的保护措施尤为重要。本文通过研究对古尔班通古特沙漠建群种梭梭与白梭梭对降水再配,0～100土层内的根系分布和同化枝的水分特性,来分析梭梭与白梭梭如何利用降雨,及二者利用降雨有效性之间的差异。结果发现：(1)在30mm/h的降雨强度下,梭梭与白梭梭的茎流率、穿透率、截留率分别为7.3±0.47%、85.0±0.43%、7.7±0.71%和6.7±0.23%、84.1±1.05%、9.2±1.04%；在20mm/h的降雨强度下,梭梭与白梭梭的茎流率、穿透率、截留率分别为16.7±1.37%、77.8±0.78%、5.3±0.77%和19.2±1.42%、75.6±1.06%、5.2±0.79%。方差分析表明梭梭与白梭梭在相同的降雨强度下,对降雨的再分配无显著差异,但是降雨强度可以显著影响其各自降雨的再分配。(2)回归分析表明,茎流量和穿透水量与降雨量之间存在显著的线性关系,截留量与穿透水量之间呈指数关系；茎流率、穿透率和截留率与降雨量之间均呈显著的对数关系。(3)无论在哪种降雨强度下白梭梭的茎流汇集率均大于梭梭的汇集率。在30mm/h降雨强度下,梭梭与白梭梭汇集率平均值分别为34.1和43.1；在20mm/h的降雨强度下,梭梭与白梭梭的汇集率平均值分别为70.6和100.2。(4)梭梭与白梭梭的水平根系主要分布在0～60cm的浅层土壤里,分别占总侧根的96%和86%。白梭梭在0～60cm浅层土壤根系发达,全部侧根平均值为252.5条,其中直径<1mm的侧根平均值为207.5条。与之相对,梭梭在0～60cm的浅层土壤内侧根稀少,全部侧根平均值为25.25条,而直径<1mm的侧根几乎没有,平均值仅为0.75条。直径为1～5mm和>5mm的白梭梭侧根的水平伸展距离平均值分别为梭梭侧根水平伸展距离平均值的2.2和3.1倍。(5)梭梭与白梭梭的同化枝均可以通过同化枝吸水。在浸泡10min时,梭梭与白梭梭同化枝的吸水率分别为5.3%和4.0%；在浸泡20min后梭梭与白梭梭同化枝的吸水率就达到9.8%和7.4%。(6)自然风干失水实验的同化枝的干重鲜重比均大于吸水实验的同化枝的干重鲜重比,表明梭梭与白梭梭枝条在浸水过程中有营养元素析出,同样暗示在降雨通过冠层时,梭梭与白梭梭可以通过淋溶将营养元素输送到冠下,尤其是植株基部。综合以上研究可以认为,白梭梭主要通过增加茎流和地下根系协同作用,来充分的利用降雨；梭梭则只能十分有限的利用降雨,而趋向于利用地下水。更多还原

【Abstract】 Water is the main limiting factor of the vegetation that growth in arid areas, so rainfall use efficiency of arid vegetation is very important. Haloxylon ammodendron and Haloxylon persicum are dominant species of Gurbantonggut desert, so study the water use mechanism of them is very important to predict the develop of population and give the scientific protect measurement in the climate change background. This paper in order to analysis how H. ammodendron and H. persicum use of rainfall, and rainfall use efficiency different of the two species by study rainfall redistribution, root distribution in less than 100cm depth and the water traits of the two species. The results showed that:(1) In 30mm/h rainfall intensity, stemflow, throughfall, interception of H. ammodendron and H. persicum are 7.3±0.47%,85.0±0.43%,7.7±0.71% and 6.7±0.23%,84.1±1.05%, 9.2±1.04%; in 20mm/h rainfall intensity, stemflow, throughfall, interception of H. ammodendron and H. persicum are 16.7±1.37%,77.8±0.78%,5.3±0.77% and 19.2±1.42%, 75.6±1.06%,5.2±0.79%. AVNOA shows that rainfall redistribution was no significant difference of H. ammodendron and H. persicum in the same rainfall intensity, but rainfall intensity can significantly affect their rainfall redistribution, respectively.(2) Regression analysis indicate that stemflow(mm) and throughfall(mm) of H. ammodendron and H. persicum are significant linear relationship and interception(mm) is a significant exponentially with rainfall depth. Stemflow rate, throughfall rate and interception rate are significant logarithmic relationship with rainfall depth.(3) Whether in each of the two simulate rainfall intensity, funneling ratio of H. persicum is large than it of H. ammodendron, In 30mm/h rainfall intensity, the average funneling ration of H. ammodendron and H. persicum are 34.1 and 43.1, respectively; in 30mm/h rainfall intensity, the average funneling ration of H. ammodendron and H. persicum are 70.6 and 100.2, respectively.(4) The lateral root of H, ammodendron and H. persicum mainly distribute in 0～60cm soil layer, they are occupied 96% and 86% of all lateral roots. The lateral roots of H. persicum are very abundance in 0-60cm soil layer, the average number of all lateral roots is 252.5, but in which diameter<lmm is 207.5. In contrast, lateral roots of H. ammodendron is very few the average number of all lateral roots is 25.25, but in which diameter<lmm is only 0.75. H. persicum lateral root average horizontal spread distance are 2.2 and 3.1times of H. ammodendron, with diameter of 1～5mm and >5mm.(5) H. ammodendron and H. persicum can absorb water by assimilation twig. When submerge in water for 10 minutes the assimilation twig water absorption are 5.3% and 4.0%; for 20 minutes, the water absorption are 9.8% and 7.4%. (6) The dry weight of air dry water loss experiment assimilation twig is larger than it of assimilation twig water absorb experiment of the two species. This indicates that the assimilation twig has loss nutrient when it is submerged in water, this also implies that stemflow and throughfall can concentrate nutrient from the assimilation twig.Summarize the study above can conclude that H. persicum use rainfall more efficiency by distribute more water to stemflow and cooperate with root distribution. H. ammodendron use rainfall very little, but prefer to use ground water.更多还原