【作者】 郝岩松；

【导师】 万福绪；

【作者基本信息】 南京林业大学 ， 生态学， 2013， 博士

【摘要】 墨西哥柏（Cupressus lusitanica Mill.）具有耐干旱瘠薄、耐寒和病虫害少等优良特性，并且对石灰岩山地适应性强，可作为我国低、中海拔地区石灰岩山地困难立地造林先锋树种，是石漠化治理的主要树种之一。目前已有大量研究表明酸雨对不同种类植物生理学特性的影响具有复杂性和差异性，而有关酸雨对引种植物墨西哥柏生理学特性影响的研究尚未见报道。本研究拟通过分析模拟酸雨对墨西哥柏幼苗光合生理特性的影响，以期为研究外来植物在我国南方酸雨胁迫区的引种推广提供理论依据。主要研究结果如下：（1）pH3.0、pH4.0和pH5.0三种不同强度模拟酸雨处理均抑制了墨西哥柏幼苗的光合速率，且模拟酸雨的pH值越低，其对墨西哥柏幼苗光合速率的抑制作用也越强。墨西哥柏幼苗的净光合速率（Pn）与大气温度（AT）、气孔导度（Gs）、胞间CO₂浓度（Ci）、蒸腾速率（Tr）、叶面饱和水汽压亏缺（Vpdl）、太阳辐射强度（PAR）和水分利用效率（WUE）均呈显著线性相关关系（P＜0.05），说明墨西哥柏幼苗Pn的日进程与Gs、Ci、Tr、Vpdl、PAR、WUE等指标关系密切。（2）三种不同强度模拟酸雨处理均导致墨西哥柏幼苗光补偿点（LCP）升高，并且暗呼吸速率增大，表明酸雨胁迫增加了墨西哥柏幼苗对光合产物的消耗，降低了其对弱光的利用能力。（3）三种不同强度模拟酸雨处理对墨西哥柏幼苗光饱和点（LSP）和表观光量子效率（AQE）没有显著性影响，但其最大净光合速率显著下降，表明酸雨胁迫能够降低墨西哥柏幼苗对强光的利用能力。（4）三种不同强度模拟酸雨处理后，墨西哥柏幼苗由Rubisco限制的潜在CO₂同化速率（Wc）、由RuBP限制的潜在CO₂同化速率（Wj）及由TPU限制的潜在CO₂同化速率（Wp）均有不同程度的下降，同时三种模拟酸雨处理均显著降低了墨西哥柏幼苗的Vcmax、Jmax和TPU，表明模拟酸雨处理对墨西哥柏幼苗的光合-CO₂响应产生了一定的抑制。（5）三种不同强度模拟酸雨处理后，墨西哥柏幼苗的表观羧化效率（CE）显著降低，表明酸雨胁迫显著降低了墨西哥柏幼苗对CO₂的利用能力，且pH值越低其抑制作用越强。（6）三种不同强度模拟酸雨处理均未对墨西哥柏幼苗的CO₂补偿点和光呼吸速率产生显著影响，一定程度上反映出墨西哥柏幼苗对酸雨胁迫具有一定的适应性。（7）三种不同强度模拟酸雨处理后，墨西哥柏幼苗的蒸腾速率变化趋势一致表现为：pH5.0＞CK＞pH4.0＞pH3.0，说明轻度酸雨胁迫促进了墨西哥柏幼苗蒸腾速率的提高，而中度和重度酸雨胁迫会抑制墨西哥柏幼苗的蒸腾速率。（8）三种不同强度模拟酸雨处理后，墨西哥柏幼苗的Fv/Fm值存在着明显的季节变化，与对照处理相比，模拟酸雨处理后墨西哥柏幼苗的最大光化学量子效率（Fv/Fm）表现出一致的下降趋势，表明酸雨胁迫对墨西哥柏幼苗PSⅡ最大光量子产量具有一定的抑制作用。（9）三种不同强度模拟酸雨处理后，墨西哥柏幼苗的F_v’/F_m’均表现出增大趋势，表明酸雨促进了光下开放的PSII反应中心激发能捕获效率的提升。同时模拟酸雨处理后墨西哥柏幼苗ΦPSII、ETR、qP、NPQ的变化并无一致规律性，表明墨西哥柏幼苗对酸雨胁迫可能具有一定的生理适应能力和自我保护能力。综上所述，模拟酸雨对墨西哥柏幼苗的光合生理特性产生了较为复杂的影响，总体上表现了对光合作用的抑制，可能会影响引种植物墨西哥柏在酸雨胁迫区域生产潜力的下降，但同时也反映了墨西哥柏在酸雨胁迫区域具有一定的生理适应能力。我们的研究可为墨西哥柏在我国南方酸雨沉降区的引种栽培提供一定理论参考。更多还原

【Abstract】 Mexican cypress （Cupressus lusitanica Mill.） has excellent characteristics such as cansurvive in dry and barren soil conditions or in cold region with adequate adaptability andresistance, and rare injured by pests or diseases. So it can be selected as pioneer species whenafforested in the limestone soil conditions or in rocky desertification controlling for its strongadaptability. There are lots of studies have shown the impacts of acid rain on plantphysiological characteristics, and the results are very different due to the different species andenvironmental conditions, but the effects of acid rain on the physiological characteristics ofMexican cypress has not been reported. In this study, the effects of simulated acid rain on thephotosynthetic physiological characteristics of Mexican cypress seedlings were investigated, inorder to provide a theoretical basis for the introduction of exotic plant of Mexican cypress in theacid rain stress area in southern China. The main findings are as follows:（1） Three different simulated acid rain treatments with pH3.0, pH4.0and pH5.0decreasedthe photosynthetic rates of Mexican cypress seedlings, the lower pH value of simulated acid rain,and the stronger restraint of photosynthetic rates of Mexican cypress seedlings. The netphotosynthetic rate（Pn） of Mexican cypress seedlings significantly linear correlated to airtemperature （AT）, stomatal conductance （Gs）, intercellular CO₂concentration （Ci）, transpirationrate（Tr）, leaf saturation vapor pressure deficit（Vpdl）, sun radiation intensity（PAR） and water useefficiency（WUE）（P <0.05）, showing that the diurnal Pn of Mexican cypress seedlings areclosely regulated by the changes of Gs, Ci, Tr, Vpdl, PAR, WUE and other indicators in thedaytime.（2） Three different simulated acid rain treatments all led to the elevation of the lightcompensation point （LCP） of Mexican cypress seedlings, and increased the dark respiration rates,indicating that the acid rain stress on Mexican cypress seedlings increase the consumption ofphotosynthetic products and thus reduce its ability to utilize low intensity light.（3） Three different simulated acid rain treatments did not significantly affect the lightsaturation point （LSP） and apparent quantum efficiency （AQE） of Mexican cypress seedlings, butits maximum net photosynthetic rate was significantly decreased, show that acid rain stress canreduce the ability of Mexican cypress seedlings to use high intensity light.（4） Three different simulated acid rain treatments all led to the decrease of the potential CO₂assimilation rates of WC, WJ, WPof Mexican cypress seedlings with a vary degree, which arelimited by Rubisco, RuBP, TPU respectively. And the Vcmax, Jmax and TPU of the threesimulated acid rain treatments were significantly lower than the control treatment of the Mexicancypress seedlings, showing that simulated acid rain has a restraint on the photosynthesis-CO₂response of Mexican cypress seedlings. （5） Three different simulated acid rain treatments all led to the significant decrease ofapparent carboxylation efficiency （CE） of the Mexican cypress seedlings, indicating that acid rainstress can significantly reduce the ability of Mexican cypress seedlings to use of CO₂, and there isa stronger inhibition under a lower pH value treatment.（6） Three different simulated acid rain treatments did not significantly affect the CO₂compensation point and photorespiration rate of the Mexican cypress seedlings, indicating thedefinite adaptation of Mexican cypress seedlings to the acid rain stress.（7） The transpiration rates of Mexican cypress seedlings has a consistent trends as: pH5.0>CK> pH4.0> pH3.0, which showed that mildly acid rain stress can increase the transpirationrates of Mexican cypress seedlings, while the moderate and severe acid rain stress can suppressthe transpiration rates of Mexican cypress seedlings.（8） There are significant seasonal variations of Fv/Fm values of Mexican cypress seedlings.Three different simulated acid rain treatments all decreased the maximum photochemicalefficiency （Fv/Fm） of Mexican cypress seedlings when compared with the control treatment,showing that the definite inhibition of acid rain stress on the maximum quantum yield in PS II ofMexican cypress seedlings.（9） Three different simulated acid rain treatments all increased the F_v’/F_m’ values ofMexican cypress seedlings, showing that acid rain stress can promote the capture efficiency oflight excitation energy in the open PSII reaction centers.At the same time, changes of ΦPSII, ETR, qP, NPQ had no consistent regularity under thethree different simulated acid rain treatments, indicating that Mexican cypress seedlings mayhave some physiological adaptability and ability to protect themselves under the acid rain stress.In summary, simulated acid rain produced very complex effects on the photosyntheticphysiological characteristics of the Mexican cypress seedlings, it totally inhibited thephotosynthesis of Mexican cypress seedlings, thus might decreased the potential productivity ofMexican cypress seedlings when afforested in an acid rain stress area, but there also were thephysiological adaptability of Mexican cypress seedlings to the acid rain stress. Our research canprovide theoretical basis for the introduction of Mexican cypress seedlings and afforested in theacid rain region in southern China.更多还原