【作者】 廖飞勇；

【导师】 何平；

【作者基本信息】 中南林学院 ， 森林培育学， 2002， 博士

【摘要】 油桐（Vernicia fordii Hemsl．）是我国特有的用材和用油两用树种，具有很高的经济价值。但是，油桐对SO2非常敏感，SO2污染严重影响其产量。SO2对于植物生长发育的影响虽有许多研究，但大都是短时间、高浓度处理和破坏性研究为主；对光合机理影响的研究也是以碳同化为主，而对光合能量转换及其机理影响的研究很少，对树木的研究也就更少。因此，研究长期低浓度SO2对油桐光合能量转换效率及机理的影响，不仅能了解SO2对光合能量代谢的影响和光合能量转换效率的机理，同时对桐油生产也具有很重要的实践意义。我们采用与自然条件相近的野外开顶式熏气装置，用0.8571mg／m³的低浓度SO2长期处理油桐苗木，用近期发展起来的对植物无伤害作用的荧光测定技术和叶红外820nm吸收测定技术，对长期低浓度SO2对光合能量转换效率及其机理进行了研究。 研究结果表明SO2处理明显减缓油桐生长。SO₂熏气处理引起叶片变小、绿色减退，叶柄之间的距离缩短，叶柄长度变短。熏气处理102天以后，一、二和三年生苗木处理的叶面积分别只有对照的67.87％、48.99％和52.84％。 SO2熏气处理使油桐对光能的捕获量下降。SO2熏气处理改变了叶绿素b吸收光谱性状，引起叶绿素在665nm处的吸收峰消失。它使叶绿素a最大荧光峰从677.7nm移到672.1nm；引起叶绿素b的荧光峰从667.2nm移到669.7nm，引起类胡萝卜素在671.2nm处的荧光峰明显增强，731.5nm处的荧光峰几乎消失。SO2熏气后处理100天左右以后，一、二和三年生处理苗木的总叶绿素含量分别是对照的73.31％、72.84％和68.04％，类胡萝卜素分别是对照的1.0725、1.3898和0.6232倍；Car／TCh1比值随着熏气时间的延长而升高，熏气100天后，一、二和三年生苗木处理的值分别是对照的1.4031、1.9080和1.0971倍。 在不同测定环境对叶绿素荧光的测定结果显示，在0.8571mg／m3SO2环境下，油桐光合能量传递效率低，测得的光合ETR降低，Yield下降，qN也减小，qP大幅度降低；在2％O2的环境条件下油桐光合能量分配受到影响，测得的可变荧光产量降低，ErR降低，Yield下降，qN增加。 SO2熏气处理使光合能量转换和传递效率下降。SO2熏气处理降低了PSII的光能转换效率、潜在活性和电子传递效率。SO2熏气处理100天以后，一、二和三年生苗木处理的F0/TCh1分别是对照的1.6359、1.2938和1.8250倍；处理的Fm／TCh1分别是对照的65.53％、36.88％和80.07％；处理的Fv／Fm别是对照的90.13％、72.17％和94.96％。SO2熏气处理引起qP/TCh1、ETR／TCh1首先上升，处理30天左右以后处理开始下降，到处理100天时其下降达到最大。Ft/TCh1和qN／TCh1的变化与qP／TCh1和ETR／TCh1的变化相反。SO2熏气处理对于荧光的OIP的曲线过程没有明显的影响。 SO2熏气处理降低了PSI的光能转换效率、潜在活性和电子传递效率。SO2熏气处理100天以后，二、三年生苗木处理的Iv／Im分别是对照的48％、84％；处理的Iv／I0分别是对照的52％、78％。SO2处理以后（Iv／Lv）／TCh1的增加和（Im/L0）／TCh1的降低说明SO2处理使PSI中心的结构受到破坏，功能受到影响，光能转换效率下降。 SO2熏气处理引起能量消耗的明显增加。处理100天后，一、二和三年生苗木处理的呼吸速率分别是对照的1.6455、1.0864和1.5524倍。熏气93天后，一年生苗木处理的乙醇酸氧化酶活力是对照的1.8078倍，熏气129天后，三年生苗木的乙醇酸氧化酶活力是对照的2.3397倍。处理100天以后，二、三年生苗木处理多酚氧化酶的活性分别是对照的5.7551、2.1989倍；它们的过氧化物酶活性则是对照的4.8484、15.6403倍。SO2熏气后清除过氧化 博 士 学 位 论 文物的其它同工酶被启动，表现为三年生苗木经SOZ处理 120天后处理叶片中过氧化物同工酶谱中增加了迁移率为0．0297、0．0597、0．0896、0．2537的四条谱带。502熏气处理引起光呼吸的明显增加。熏气30mins流向光呼吸的能量增加 13％，熏气108天后流向光呼吸的能量增加 82％。熏气处理 110大后假循环电子传递所耗散的能量增加 1．7倍。 SO。处理引起可溶性蛋白含量增加。一、二和三年生苗木SO。熏气100天后，叶片中可溶性蛋白的含量分别是对照的1．0382、1．2929和l．2205倍。 So处理引起流向光合暗反应光合能量减少。熏气引起表观光合电子传递速率明显下降。。年生苗木熏气处理 83天、三年生苗木处理 108天后在 350 p thol 6leCt＊m．／·S条件下测定，它们的ETR分别是对照的85．71％、66．92％。熏气处理100天以后，一、H和三年生苗木的光合速率分别是对照的68－96％、47．97％和68．76％。502熏气处理天100天后一、二和三年生苗木叶片中可溶性糖的含量分别只有对照的89．69％、62．91％和85．28％。 SO。处理弓I起能量吸收、传递、转换效率的下降主要是SO。处理引起细胞结构的变化，S0z处理引起细胞膜结构变化而引起电解质的外渗。三年生苗木经SO。处理115天后的电导率是对照的1．3509倍。三年生苗木502熏气处理110天后引起细胞内膜过氧化作用增强，表现为处理叶片丙二醛含量是对照的1．4151倍。气相?更多还原

【Abstract】 Vernicia fordii (Oil Tung)is a timber and oil tree with high economic value .occurs originally only in China. It is very sensitive to SOz. There were many reports about severe damage of oil Tung tree plantation by SOz pollution , which lowered down the income of farmers in the mountain area in southern China. Therefore, it is very important to know the mechanism of SOz affecting on oil Tung. SOz pollution is a worldwide environment problem, and has been studied over 100 years. The most studies were focused on the influence of SOz on photosynthetic organ e.g. chloroplast in vitro and fumigating with high concentrations of SOz. Thus, those experiments could not reflect the real state of plant suffering from SOz pollution in nature condition and it was very difficult to find out the mechanism of SOz affecting photosynthesis. In most situations, the research conclusion resulted from disturbed chloroplasts. On the other hand, the studies on photosynthesis mechanism were mainly focused on carbon assimilation, little on photosynthetic energy transition and its mechanism. And the such studies on tress were even lesser. . Thus, it is not only important to find out the effect of SOz on the photosynthetic energy metabolism for photosynthetic theory, but also important for improving the farmer’ s income from the Oil Tung growing in the mountain.. The affect of a long -term low concentration SOz, which was 0.8571mg/m3, on the photosynthetic energy transition in Oil Tung was investigated by means of chlorophyll fluorescent technique and leaf 820nm absorbance changing technique and top-open chambers.The results showed that SOz fumigation depressed the growth of oil Tung, diminished the leaves area, shortened the length of leaves and shortened the distance between nearby leaves stipe. After SOz treated for 102 days, the leaf areas of one, two and three years old seedlings were only 67.87 percent, 48.99 percent, 52.84 percent of those of control respectively.The leaf biomasses decreased obviously after SOz fumigation for 102 days, the dry biomasses per cm2of one, two and three years old seedlings were only 84. 35percent, 78.04percent, 79.94percent of those of control respectively. And the fresh biomasses per cm2 were 85.02percent, 76.OOpercent, 74.90 percent of that of control respectively.SOz fumigation shifted the maximal absorbance peak of chlorophyll a from 677. 7 nm to 672. 1 nm and the maximal fluorescence peak of chlorophyll b from 667. 2nm to 669. 7nm. The absorbance peak of chlorophyll b at 665nm vanished by SOz fumigation.The fluorescence peak of carotid at 671. 2nm was enhanced, but the fluorescence peak of carotid at 731. 5nm almost vanished. After SOa treated for 100 days, the contents of total chlorophyll, carotid of one, two and three years old seedlings were 73.31 percent, 72.84 percent , 68.04 percent of those of control respectively .And the contents of carotid (Car) of SQj treated plants s 1. 0725, 1. 3898,0.6232 times those of the control respectively. But the value of Carotid /total chlorophyll (TChl) increased with the fumigation tine prolonging. The value of carotid/total chlorophyll of treatment 1.4031,1.9080,1.0971 times that of the control respectively.S02 decreased the produce of apparent photosynthetic electron transport (ETR), over photochemical quantum yield (Yield), non-photochemical quenching (q? and photochemical quenching (qP). The figures of variable fluorescence (Ft), ETR, Yield were decreased when measured in the air containing 2% of Oxygen. While qP increased in such a condition..S02 fumigation decreased the efficiency of energy transition. Photosynthetic energy transition efficiency, potential activity and electron transition efficiency of PSII were depressed by SOz fumigation. After treated for 100 days, F0/TChl of PSII of one, two and three years old seedlings were 1.6359,1.2938,1.8250 tines of the control respectively, which showed that the energy did not engage in photochemical reaction increased. F.(maximal fluorescence)/TChl of PSII of one, two and three years ol更多还原