【作者】 何明；

【导师】 翟明普；

【作者基本信息】 北京林业大学 ， 森林培育， 2005， 硕士

【摘要】 刺槐（Robinia persudoscacia）是我国北方重要的造林树种,广泛应用于水土保持、防风固沙、改良土壤和“四旁”绿化等。在西部防护林工程中,在多风、干旱、寒冷地区的沟边、河滩、沙谷地带大力营造刺槐林,常因失水过多,导致水分代谢不平衡,引起梢部干枯。为了发挥刺槐的水土保持作用,更好地绿化干旱贫瘠的土地,本文通过盆栽模拟试验对干旱条件下刺槐生长、生理进行了系统的研究,并取得了一些有价值的结论。 1.对供试刺槐无性系（皖一、鲁一、鲁78、鲁59）进行盆栽抗旱性研究,主要研究了干旱处理下的刺槐无性系浄光合速率（Pn）、蒸腾速率（Tr）、水分利用效率（WUE）日变化以及叶绿素含量变化,Pn日变化有明显的“双峰”,在干旱12天时78和L1还有两个较小的“双峰”,W₁和59Pn呈缓慢下降趋势,干旱20天时Pn明显下降。供水良好条件下L₇₈和W₁最大蒸腾速率出现的时间与光合午休时间一致,59和L₁Tr变化幅度不大。干旱10天总体Tr下降,但是波动幅度相对较大,干旱20天时刺槐苗Tr继续降低,最高值小于3mmolm^-2s^-1。供水良好情况下,L₇₈和59有相对较高的WUE干旱10天和20天时L₁有相对较高的WUE,干旱10天和20天WUE明显升高,一定范围的干旱可以提高WUE。L₁干旱20天时WUE比10天略有下降。刺槐无性系叶绿素含量随干旱加剧先降低后升高,干旱10天时叶绿素对干旱敏感由干旱胁迫引起叶绿素分解,但是严重干旱下叶片失水导致单位质量的叶绿素含量升高。 2.通过盆栽试验研究皖一和鲁一在干旱条件下增施氮磷肥后光合、荧光参数变化,试验表明光合特性中,LSP、LCP显著影响因素主要是水分和氮磷交互作用,增施氮磷肥提高刺槐叶片的LSP。L₁的LSP高于W₁。水分胁迫抑制了苗高生长,增施氮肥减缓这种抑制。磷素对苗高生长影响不显著。水分胁迫降低了Fo,而Fv变化不明显。水分胁迫降低了Fv/Fm。增施肥料可一定程度上减缓Fo、Fv、Fv/Fm的降低,这也是施肥可以减缓水分胁迫对PSⅡ反应中心的破坏。 3.不同水分梯度下刺槐无性系增施氮素、磷素对刺槐无性系光合特性、叶绿素荧光参数、生长以及植株营养元素的影响。Pn受水分胁迫影响显著,不同水分胁迫Pn依次:轻度干旱>中度干旱>重度干旱,同时施氮量也显著影响Pn,适量氮肥可以提高Pn。中度、重度水分胁迫下的刺槐叶片的WUE要高于轻度水分胁迫下的,适当的干旱胁迫可以提高植物的WUE。中度水分胁迫下增施氮肥能提高刺槐根茎叶的含水量,重度水分胁迫下这种提高不明显。氮素和水分对苗高和地径增长量影响显著。随干旱时间的延长脯氨酸含量增加显著,增施氮肥也提高了脯氨酸含量。轻度水分胁迫时叶片水势较低,随胁迫加剧叶片水势越高,增施氮肥一定程度上提高叶片水势。适当的水分胁迫有利于根系氮积累,不同水分梯度下根系含氮量依次为:中度干旱>重度干旱>轻度干旱。增施氮肥促进茎钙积累,叶片钙含量随施氮量增加而增加。更多还原

【Abstract】 The Black Locust is an important tree species for afforestation in the North of China, which is applied to the water and soil conservation, wind-break and blown sand control, improving soil and turning the " four sides " green and so on. In the western shelter forest projects, Black Locust is planted in the zone of ditch, river shoal, sand valley of the windy, droughty, cold area, which caused the water metabolism imbalance and made its tip withered because of excessive water deficit. In order to make full use of Black Locust, the paper studied systematically its growth and physiology on drought condition and made some valuable conclusions by way of the combination of pot-culture.1. Based on the experiments in the four black locust clones (W₁、 L₁、 L₇₈、 L₅₉), The diurnal course of Pn、 Tr、WUE and the change of chlorophyll content were studied, Net photosynthetic rate has "double-hump", under twelve days drought the diurnal course of Pn of L₇₈ and L₁ could keep "double-hump", but the Pn of W₁ and L59 fall down slowly. The Pn of the four black locust clones dramatic decline when they are under twenty days water stress. The appearing time of maximal transpiration rate is conformity with the midday depression of photosynthesis when supply of water. The amplitude of variation of L59 and L₁’S transpiration rate is small. After ten days water stress the transpiration rate of all seedlings are fallen down and vary within wide limits. The transpiration rate still fall down when they are after 20 days water stress. The maximum value of transpiration is less than 3 mmolm^-2s^-1. The clones of L₇₈ and L₅₉ have the higher WUE when supply water to them. The WUE of the black locust clones are all raised. A given extent the water stress can improve the WUE. The chlorophyll content of black locust clones declined with the water stress exacerbation, and then up. It is because the chlorophyll can decompounded under drought stress.2. Photosynthesis and chlorophyll fluorescence parameter were studied in the experiment. Through the study of photosynthetic characteristic we know the important3. Influencing factors of LSP and LCP are the water stress levels and the interaction of nitrogen and phosphorus. Applying nitrogen and phosphorus to the seedlings can raise LSP. The L₁’s LSP is higher than W₁’s. Water stress inhibit the height of seedling, applying nitrogen may slow up the inhibition. The growth of Seedling height was not influenced significantly by Applying phosphorus. Fo and Fv/Fm took from water stress, while Fv didn’t change remarkably. To some extent, Fo, Fv, Fv/Fm fell by applying fertilizer because it could slow up PS II reaction center’s damage from water stress.4. The physiological parameters, including photosynthesis characteristics, chlorophyll fluorescence, growth and plant nutrient element of Black Locust clones, influenced by applying nitrogen and phosphorus in different levels of water stress. Net photosynthetic rate was influenced significantly by water stress. The sequence of Pn in different levels of water stress is slight>moderate>severe drought. At the same time, Pn was influenced significantly by applying nitrogen and Pn could be improved by applying proper amount nitrogen. The WUE of Black Locust leaves in moderate, severe water drought was higher than the one of slight drought, so WUE could be improved in proper water stress. The water content of root, stem and leaf could be improved by applying nitrogen in moderate drought, and it couldn’t be improved remarkably in severe drought. The growth amount of seedling height and collar-diameter was influenced significantly by nitrogen and water. Proline content increased significantly with the prolong of drought time, to some extent, which could be improved by applying nitrogen. The leaf potential in slight drought was higher than the one of severe drought. To some degree, leaf potential could be improved by applying nitrogen. Proper drought could benefit to nitrogen accumulation of root. The sequence of root nitrogen conte更多还原