【作者】 赵凤君；

【导师】 沈应柏； 高荣孚； 苏晓华；

【作者基本信息】 北京林业大学 ， 植物学， 2004， 硕士

【摘要】 随着世界性干旱缺水趋势的日益紧追，越来越多的农林科学家致力于植物抗旱节水的研究，而只有提高植物自身的水分利用效率（WUE），让每一滴水生产出更多的干物质，才有可能取得节水研究上的新突破。杨树是最适合的短轮伐期工业用材集约经营树种，快速、高效地选育出速生又高WUE的品系，是杨树育种工作者的迫切要求。本文通过模拟自然干旱和土壤逐渐干旱两种方法对黑杨新品系间的WUE进行了比较，并对WUE差异的机理进行了初步研究，以期为林木育种实践提供可行的方法和理论依据。研究结果显示：黑杨新品系间WUE存在显著差异，J₂、J₆、J₇、J₈、J₉是生物量大，WUE高的优良品系；叶片高δ ¹³C值是品系高WUE的指示指标；WUE高的品系在模拟自然干旱胁迫下功能叶面积下降幅度小、叶片含水率高、叶片持水力强，土壤逐渐干旱胁迫下脯氨酸、MDA积累量少，SOD、POD酶活性低。高WUE在苗木生产能力上由两方面原因引起，用水节约和光合能力强，二者缺一不可。苗木用水节约的原因可能和气孔小，频度大导致的GS较小有关。叶片光合作用积累的同化物在地下、地上器官间分配比例的差异也是引起品系间WUE的差异的一个原因，WUE高的品系具有较优的根冠比。更多还原

【Abstract】 Along with the severe drought trend all over the world, more and more scientists have dedicated to the research on plant drought resistance and water saving. But only to improve the water use efficiency (WUE) of plant, to let them produce further yield from per drop of water, the new progress may be achieved. Populus is one of the most popular trees in artificial intensive forestry, to select fast growing clones with high WUE rapidly and efficiently is exigent desire of breeding researcher. In order to provide theoretic foundation and feasible techniques for forestry breeding, difference and the mechanism of the difference of WUE in Populus clones has been studied through stimulant natural drought and gradual drought of soil. Our results indicate that the differences in Populus clones are significant, J2, J6, J7, J8, J9 are excellent clones ,their biomass are more and WUE are high; δ 13C can be as a surrogate for high WUE genotype; For high WUE clones, the decline extent of leaf area and moisture content are smaller, the leaf moisture retaining power are stronger under stimulant natural soil drought; the accumulation of proline (Pro) and malondehyde (MDA) are lower, the activity of superoxide dismutase (SOD) and peroxide enzyme (POD) are weaker. To economize on water and high photosynthetic capacity are inseparable sides of WUE difference mechanism on yielding capability, low stomatal conductance induced by big stomata frequency and small size may be the reason for water saving. The distribution ratio of photosynthate between root and shoot is another factor that may be contribute to the WUE difference mechanism, for the high WUE clones usually have optimal ratio of root to shoot.更多还原