【作者】 张贵龙；

【导师】 马新明；

【作者基本信息】 河南农业大学 ， 作物栽培学与耕作学， 2006， 硕士

【摘要】 在2004～2005年采用盆栽方法，于河南农业大学科教园区，较系统地研究了土壤汞污染对烤烟生长发育和干物质积累、光合特性和叶绿素荧光参数、生理特性和碳氮代谢、根际土壤酶活性和微生物数量、烟叶内在化学成分的影响以及汞在烟株内富集规律和土壤汞毒害阈值。试验结果表明：（1）土壤汞污染对烤烟的生长具有很强的毒害作用，能严重地抑制其生长发育，土壤汞浓度在10～120 mg．kg^-1。范围内，可使烤烟单株产量下降21.04～54.35％。根、茎、叶生长受到抑制：主根细而短，较严重时根尖带有黑色坏死斑点，侧根量少发生晚，茎秆细弱，出叶速度慢，最大叶片长和宽减小。根干重降低51.42～69.17％，株高降低2.9～26.53％，茎干重下降14.85～69.70％，烟叶干重下降7.3～46.95％，烟株干物质积累量下降3.32～30.72％。（2）土壤汞污染对烤烟光合特性和叶绿素荧光参数影响的研究结果表明；随土壤汞浓度的增加烤烟叶片气孔导度（Cond）、胞间CO₂浓度（Ci）、蒸腾速率（Tr）、叶面温度（Tleaf）和饱和蒸气压差（Vpdl）、叶片初始荧光（F₀）、最大荧光（Fm）和可变荧光（Fv）值均降低，Fv/Fm、Fv/Fo值升高。低浓度(≤30 mg．kg^-1)的汞提高烤烟叶片叶绿素含量、叶绿素a/b值、光合速率（Pn）和水分利用率（WEE），并促进恒态荧光（Fs）、光化学猝灭系数（qP）、非光化学猝灭系数qNP和光量子传递速率（ETR）升高。高浓度汞处理(>30mg．kg^-1)叶绿素含量、叶绿素a/b值和光合速率下降，水分利用率增加幅度减小，Fs、qP、qNP和ETR值下降。随土壤汞浓度升高，烟叶类胡萝卜素含量的变化不具有明显的规律性。（3）土壤汞污染对烤烟的逆境生理指标具有一定的影响；低浓度汞(≤30 mg．kg^-1)能提高烤烟叶片SOD、POD活性和根系活力，高浓度汞(>30 mg．kg^-1)降低叶片SOD、POD活性和根系活力。土壤汞污染能引起烤烟叶片脯氨酸含量、质膜透性和丙二醛含量增加，降低根系ATP酶活性。（4）土壤汞污染对烤烟碳氮代谢影响的研究结果表明；随土壤汞浓度的升高，烟叶硝酸还原酶活性和蔗糖合成酶活性呈下降趋势，谷氨酰胺合成酶活性、天冬酰胺酶活性、游离氨基酸含量和ADPG焦磷酸化酶的活性升高。当土壤汞浓度低于10 mg．kg^-1时，烤烟叶片GPT活性有少量的增加，当添加浓度高于10 mg．kg^-1时，叶片GPT活性随汞浓度的升高而降低。低浓度汞(≤30 mg．kg^-1)能刺激烟叶蔗糖磷酸合成酶活性的提高，高浓度汞(>30 mg．kg^-1)对蔗糖磷酸合成酶活性刺激作用减弱。随土壤汞污染浓度的增加烟叶中的淀粉合成酶活性总体表现增加，但增加的幅度随汞浓度升高逐渐降低。（5）烤烟根际土壤酶和土壤微生物对汞的响应规律表明；土壤汞浓度在10～120 mg．kg^-1范围内，对土壤尿酶活性有明显的抑制作用，且随汞浓度的增加，酶活性的抑制作用加强，土壤色氨酸脱羧酶活性对土壤汞响应没有明显的规律性。土壤汞浓度10～60 mg．kg^-1范围时根际蛋白酶活性升高，当土壤汞浓度大于60 mg．kg^-1，酶活性快速下降。随土壤汞浓度的升高土壤细菌数量急剧下降。在汞浓度低于30 mg．kg^-1时真菌数量增加，汞浓度高于30 mg．kg^-1时降低。（6）汞对烤后烟叶内在化学成分的影响及其在烟株内的富集规律：在土壤汞浓度10 mg．kg^-1，30 mg．kg^-1时，烟叶中的淀粉、可溶性总糖和还原糖含量均比对照高，当土壤汞浓度高于30mg．kg^-1时，随土壤汞浓度的升高，烟叶中的淀粉、可溶性总糖和还原糖含量明显降低。随着土壤汞浓度的增加各部位烟叶的总氮、烟碱含量和钾含量在低浓度(≤30 mg．kg^-1)时表现增加，在高浓度(>30 mg．kg^-1)时表现降低。当土壤汞浓度低于60 mg．kg^-1时，下部叶氯离子含量较对照高，当汞浓度大于60 mg．kg^-1时，氯离子含量明显低于对照。在中部叶和上部叶中，氯离子含量随土壤汞浓度的增加而降低。（7）汞在烟株各器官残留浓度总体表现为：根>叶>茎，下部叶>中部叶>上部叶。且烤烟各器官中汞的浓度与土壤汞浓度相关程度均达极显著水平。以国家粮食卫生标准(Hg≤0.01 mg．kg^-1)确定汞对烤烟生长产生毒害的标准，汞对烤烟的毒害阈值的为3.287 mg．kg^-1。根据本试验的研究，土壤汞污染对烤烟的农艺形状、生理特性和烟叶内在化学成分具有明显的影响。并且对根际土壤酶活性和微生物的生长具有一定的抑制作用。另外汞能在烟株内富集，尤其在烤烟叶片中能大量富集，严重影响烟叶的品质。烟叶中汞含量过高，对吸烟者的身体健康造成严重危害。所以对于土壤汞浓度高于毒害阈值的地区不宜作为无公害优质烟叶生产基地。更多还原

【Abstract】 The effects of Mercury on Growth of Flue-cured Tobacco were experimented in Pot And Critical index of Mercury Toxicity was Studied at Henan Agricultural University and Ddmonstration Plot of Scientific Research and Teaching during 2004-2005.The results at follows:Firstly Mercury added to soil has severe impacted on Growth of Tobacco. when mercury concentration was 10 - 120mg. kg^-1 in soil,the yield of Flue-cured tobacoo was decreased 21. 04-54. 35%. Growth of the roots were restrained, the roots was short ,thin and brown in the soil. with increasing of mercury concentration in the soil,dry weightily of tobacoo stem and leaf were decreased in evidence .when mercury concentration was under 30mg. kg^-1 in the soil,the dry weightily of tobacoo was slow decreased .But when mercury concentration was above 30mg/kg in the soil, the dry weightily was rapid decreased.Secondly The effects of Mercury in soil on photosynthesis fluorescence characters were studied, results show when concentration of mercury in soil was in 10mg. kg^-1,30mg. kg^-1 the net photosynathetic rate （Pn）,water utilize rate （WUE）,.maximal PS II light energy transformation efficiency（Fv/Fm）, PS II activity（Fv/Fo）, steady fluorescence, the photochemical quenching coefficient（qP）,the non-photochemical quenching coefficient（qN） and the apparent photosynthetic electron transport rate （ETR） were increased, but when concentration of mercury in soil was in 60 and 90 and 120mg. kg^-1,thery were decreased .as increasing of the concentration of Hg in soil ,stoma conductance （Cond）,transpiration rate （Tr）, intercellular CO₂ concentration,leaf temperature , vapor pressuer deficit,beginning fluorescence ,variable fluorescence,maximum fluorescence decreased.Thirdly the effects of mercury on physiology characters in tobacoo were studied ,the results show when the concentration of mercury concentration in soil was under 30mg. kg ^-1or30mg. kg^-1 ,the content of chlorophyll decreased. but when the concentration of mercury in soil was above 30mg/kg, the content of chlorophyll increased, with the increasing of mercury in soil, the chlorophyll a/b decreased and the changes of carotenoid content do not present evidence rule . watery mecury(10and30mg. kg^-1) can improve activity of SOD and POD in tobacco leaf as well activity of roots, thick mecury (60 and 90 and 120mg. kg^-1) ,however, can dropped their activity, as the increasing of mercury concentration in soil ,but the content of free praline and MDA and the conductance rate in tobacoo leaf and the activity of ATPase in roots decreased with the increasing concentration of mercury.Forthly the results of study on effects of mercury on metabolism of carbohydrate and nitrogen in flue-cured Tobacco indicate that nitrate reductase （NR） activity droped with the increasing concentration of mercury in soil. Activity of Gultamate-pyruvate transaminase （GPT） had a small quantity of increase under the treatment concentration of 10 mg. kg^-1 Hg or 10 mg. kg^-1 Hg . when the treatment concentration above 10 mg. kg^-1 ,the activity of GPT dropped with the increasing treatment concentration of Hg .mercury added in soil can improve Glutamina synthase （GS） activity, Asparaginase activity and the content of free aminophenol . Sucrose synthase activity present drop direction with the increasing treatment concentration of Hg in soil .Low concentration Hg (≤30mg. kg^-1) has a capability to improve Sucrose phosphate synthase activity ,but the capability would be weaken for higher concentration Hg (>30mg. kg^-1) .To sum up ,amylum synthase activity increased with the with the increasing treatment concentration of Hg ,but range increased decreased. In addition, mercury can improve ADPGppase activity .Fifthly Studied on effects of mercury on the enzyme activity and microbes in soil .results show that urease was significantly inhibiled by the mercury in 10-120mg. kg^-1 ,with the decreasing concentration of mercury in soil ,changes of tryptophan decarboxylase activity did not present evidence rule. Protease activity hoisted when the concentration of mercury in 10-60mg. kg^-1,but the concentration of mercury above 60mg. kg^-1, it activity decreased. Bacteria biomass droped with the increasing concentration of mercury in soil .epiphyte biomass increased under or in the concentration of 30mg/kgHg. it biomass would be decreased when the concentration above 30mg/kg.Sixthly The effects of mercury on quality of tobacoo leaf and the enrichment rule of mercury in tobacoo organs were studied, results indicated that the content of starch total soluble sugars and reducing sugars increased in the concentration of 10mg. kg^-1 Hg and 30mg. kg^-1 Hg,when the concentration of mercury above 30mg. kg^-1, their content decreased .The content of total nitrogen and nicotine and potassium increased under or in the concentration of 30mg. kg^-1 Hg,however their content decreased when the concentration of mercury above 30mg. kg^-1 .changes of chloride content as follows: when the concentration of mercury under 60mg. kg^-1, the content of chloride increased ,when the concentration of mercury above 60mg. kg^-1, the content of chloride decreased in lower leaves, the content of chloride droped with the increasing concentration of mercury.Seventh the enrichment concentration of mercury in tobacoo organs as follows: the order was roots>leaves>stems, lower leaves >middle leaves>upper leaves, the enrichment concentration of mercury in tobacoo organs were positively correlated with the mercury in soil . the concentration of 0.01 mg. kg^-1 Hg tobacoo roots as a criterion to judge whether mercury had contaminated to growth of tobacoo, result shows that the threshold value of mercury toxicity was 3. 287mg. kg^-1.According to the study, Mercury pollution in soil was harmful to growth of flue-cured tobacco to different extent ,appearance symptom as follows: the roots was short ,thin and brown;strm shorten,area of leaves be minished ,greenness of leaves become tint,even some leaves with lots of small brown spot .Besides,mercury could be mass enriched in tobacoo leaves ,and inhaled with the smoke ,which was harmful to the smoker and others who do not smoke, So it was suggested that polluted area by mercury had better restore before plant flue-cured tobacco.更多还原