【作者】 肖春旺；

【导师】 张新时；

【作者基本信息】 中国科学院植物研究所 ， 生态学， 2001， 博士

【摘要】 毛乌素沙地是中国半干旱地区典型沙地，这里的干旱生态系统对全球的水热配合格局的变化具有很灵敏的响应。随着未来全球气候变化，如温度和降水量变化，将给这里的陆地生态系统分布格局和生产力以及水分平衡带来巨大影响。故本文人工控制157.5mm、315.0mm、472.5mm和630.0mm 4种施水量水平以及25/20℃和28/23℃（白天/晚上）两种温度，来研究与模拟毛乌素沙地优势植物对水分和温度变化的响应。 以沙柳、杨柴和油蒿幼苗为研究对象，人工控制4种降水量水平来探讨它们的水分平衡对全球变化中降水量变化的响应。结果表明，随着施水量的增加，沙地贮水量及其它的变化量、湿度、蒸发量和蒸腾量均逐渐增大。并且157.5mm和315.0mm施水量的植物沙地出现水分亏缺现象。相同施水量下，沙地蓄水量和湿度均杨柴沙地＞沙柳沙地＞油蒿沙地，而植物蒸腾量却油蒿＞沙柳＞杨柴。 以沙柳和油蒿幼苗为研究对象，人工控制4种降水量水平来探讨植物气体交换过程对全球变化中降水量变化的响应。结果表明，施水量的增加显著提高了两种植物的净光合速率、蒸腾速率、气孔导度和光能利用效率，并且显著降低了叶片温度。同时，157.5mm施水量造成沙柳和油蒿的净光合速率和蒸腾速率具有显著的“午睡”现象，而充足施水却有效的解除或缓解这种“午睡”现象。 以沙柳、杨柴、油蒿和柠条幼苗为研究对象，人工控制4种降水量水平来探讨植物叶绿素荧光对全球变化中降水量变化的响应。结果表明，不同施水量对这4种植物的初始荧光、最大荧光、可变荧光和PSII光化学效率均具有显著影响。157.5mm施水量的沙柳、杨柴、油蒿和柠条以及630.0mm施水量的柠条出现明显的光抑制现象。 －11－摘要 以沙柳、杨柴、油蒿和柠条幼苗为研究对象，人工控制4种降水量水平 9来探讨植物生长对全球变化中降水量变化的响应。结果表明，施水量的增加对沙柳、油蒿和杨柴枝叶形态和生物量等都具有显著正效应。而157．smm和630．omm的施水量对柠条生长具有负作用。另外，沙柳、杨柴和油蒿根冠生物量比随着施水量增加均逐渐减小，而不同施水量的油蒿根冠生物量比之间差异不显著。 以柠条、杨柴和油蒿幼苗为研究对象，人工控制两种温度水平来探讨植物形态、生物量和气候交换特征对增温的响应。结果表明，增温显著提高了柠条和杨柴株高、叶数、叶面积、生物量、净光合速率、蒸腾速率和气孔导度，却显著降低了水分利用效率。增温对油蒿叶数＼叶大小、叶面积、生物量、蒸腾速率和气孔导度没有显著影响，却显著提高了油蒿的树高和净光合速率。柠条、杨柴和油蒿之间的种间生长和生理特征均有显著差异。更多还原

【Abstract】 Maowusu sandland is a classical semi梔ry one in China. The dry ecosystem has the much sensitive response 40 water梙eat pattern of global change there. The distribution pattern, productivity and water balance of terrestrial ecosystem are greatly affected by future global climate change, such as temperature and precipitation change. Therefore the dissertation is to investigate the response of dominant plants of Maowusu sandland to the global precipitation and temperature change by artificially controlling water supply at four levels of 157. 5mm, 315. 0mm, 472. 5mm and 630. 0mm and two temperature treatments of 25/20 0C and 28/230C (day and night). We have investigated the response of water balance to precipitation change in global change by creating an artificial control of four levels of water supply treating seedlings of Artemisia ordosica Krasch., Sa]ix psammophi]a C. Wang et Ch. Y. Yang and Hea~vsarwn mongo]icum Turcz.. The results show that sandland water storage and its variation, moisture, evaporation and transpiration increased with the increase of water supply. Plant sandland treated by 157.5mm and 315.0mm water supply appeared water deficit. The sandland water storage and moisture of IL mongo]icum sandland was larger than that of S. psa,nmnophi]a sandland, that of which was in turn higher than that of A. ordosica sandland in the same water supply treatment. But the transpiration of A. ordosica was larger than that ?IV - Abstract of S. psammophila, that of which was in turn higher that of ILL mongolicum in the same water supply treatment. It is investigated for the response of gas exchange processes of S. psammophyi]a and A. ordosica seedlings to precipitation change in global change by artificially controlling four water supply levels. The results show that the increase of water supply significantly enhanced the photosynthetic rate, transpiration rate, stomatal conductance and light use efficiency, but decreased leaf temperature of S. psamznophyi]a and A~ ordo.sica. Photosynthetic rate and transpiration rate of the two plants showed str~ongly midday depression in 157. 5mm water supply, but not or a little in full water supply. It is investigated for the response of chlorophyll fluorescence of seedlings of 8. psammophyi]a, HLmongo]icum, A.ordosica and Caragana interrnedia Kuanget H. C. Fu to precipitation ch&ige in global change by artificially controlling four water supply levels. The results show that the different water supply obviously affected the initial fluorescence, maximal fluorescence, variable fluorescence and PSII photochemical efficiency of the four plants. ~There were photoinhibition in the four plants treated by 157. 5mm water supply and in C intermedia treated by 630. 0mm water supply. It is investigated for the response of growth of seedlings of 8. psammophyi]a, IL mongo]icum, A. ordosica and C intermedia to precipitation change in global change by artificiallycontrolling four water supply levels. The results show that there were the positive effects of increasing water supply on morphology of branch and leaf and biomass of S. psammophyi]a, H. mongo]icum and A. ordosica, but the passive effects on the growth of C. interznedia treated by 157.5mm and 630. 0mm water supply. In addition, the root/shoot bidmass weight gradually decreased with the increase of water supply for更多还原