【作者】 郑聪；

【导师】 许自成；

【作者基本信息】 河南农业大学 ， 烟草学， 2010， 硕士

【摘要】 2008年在河南科技大学科教园区进行盆栽试验,研究了不同硒肥施用量及不同施用方式对烤烟生长状况、生理特性及生长过程中烟叶中硒含量的影响,提出了适宜烤烟生长的最佳硒浓度。同年在湖北省恩施州的宣恩县和咸丰县为试验地点,选取有代表性的90个土壤样本及不同品种(云烟87,云烟85和K326)和不同等级(X2F,C3F和B2F)的72个烤烟样本,分析土壤中的硒含量与烟叶中硒含量的分布特点以及二者之间的相互关系,主要研究结论如下:1、研究了硒营养对烤烟生长发育的影响。(1)土壤中适宜的硒浓度可以促进烤烟的生长。当土壤硒浓度在0~12 mg/kg时,硒对不同时期烤烟的株高、茎围、最大叶面积、有效叶数、地上部和地下部干物质的积累量均有不同程度的促进作用(P<0.05);当土壤硒浓度≥16 mg/kg时,不同时期烤烟的株高、茎围、最大叶面积、有效叶数、地上部和地下部干物积累量相比于对照均有下降。当土壤硒浓度为8 mg/kg时,每个时期的株高、茎围、地上部和地下部干物质的积累量均达到最大值。说明土壤中硒含量达到8 mg/kg时最有利于烤烟的生长发育。(2)叶面喷施适量的硒肥能够促进烤烟的生长。在烤烟10片叶和15片叶两个时期分别对其喷施不同浓度的硒溶液表明:在烤烟15片叶喷施5μg/ml硒肥更有利于促进烤烟的株高、茎围、最大叶面积、有效叶数、地上部和地下部干物质的积累量。2、研究了硒对烤烟叶绿素含量和生理酶活性的影响。(1)微量元素硒在适宜的浓度范围内(0~12 mg/kg)能够促进烤烟生长过程中叶绿素和类胡萝卜素含量的增加;当土壤硒浓度≥16 mg/kg时,各时期的叶绿素a、叶绿素b、叶绿素a+b和类胡萝卜素含量开始下降,当土壤硒浓度达到24 mg/kg时,烟叶叶片出现“黄化”现象。叶面喷施硒肥试验结果表明:在烤烟10片叶喷施2μg/ml的硒肥或是在15片叶喷施5μg/ml的硒肥最有利于增加烤烟叶片中叶绿素和类胡萝卜素的含量。叶面喷施硒肥较土壤施硒更为安全。(2)土壤施硒试验结果表明:烤烟的POD和SOD活性在不同时期均随着土壤硒浓度的升高出现了先上升后下降的趋势,说明适当的硒含量能增强烤烟的抗逆性;当硒浓度≤8 mg/kg时,各个处理烤烟的MDA含量随着硒浓度的升高而降低,当土壤硒浓度>8 mg/kg时,MDA含量又随之升高,说明过低或过高的硒浓度都不适宜烤烟生长,而适宜的硒浓度在一定程度上能缓解烤烟细胞膜脂的过氧化。硒肥可以提高烤烟的转化酶活性,土壤中硒浓度在2~12 mg/kg范围内,能够提高烤烟叶片转化酶活性,促使碳代谢的增强,碳水化合物生产量大,较高的碳代谢为烟叶的生长和其他有机化合物的形成提供了较多的碳架,利于烟草同化产物的转化和利用,无硒和高硒都使烟草叶片对光合产物的利用强度减弱;各施硒处理烤烟的NR活性在不同时期间表现为60 d>45 d>30 d>75 d;随着土壤硒浓度的提高,各时期烤烟叶片的硝酸还原酶活性都呈现先增高后降低的趋势,均在土壤硒浓度为8 mg/kg时达到最大值;当土壤硒浓度≥16 mg/kg时,各处理烤烟叶片的NR活性低于对照。(3)叶面喷施硒肥对POD活性的影响并不能在短时间内得到体现,随着生育期的延长效果越来越明显,但是SOD活性能够立即得到体现,而随着生育期的延长,硒对SOD活性的影响越来越弱。喷施硒肥之后MDA含量能够立即降低,并且能保持很长的作用时间。喷施浓度在2~10μg/ml范围内,硒肥也可以提高烤烟的转化酶活性,并且以5μg/ml浓度最佳;各处理NR活性都表现为移栽后30 d>45 d>60 d>75 d。3、研究了硒对烤烟生长发育过程中K+、总N及硒含量的影响。随着烤烟生育期的延长,各处理烤烟的全氮和钾含量逐渐降低。随着土壤硒含量的增加,每个时期烤烟的全氮含量呈现先降低后增加的趋势,而钾含量呈现先增加后降低的趋势。低浓度硒(0~12 mg/kg)可以降低烤烟生长过程中的全氮含量,促进烤烟生长过程中钾含量的提高。当土壤硒浓度为8 mg/kg时,每个时期的全氮含量达到最小值,而钾含量达到最大值。喷施硒肥后,每个时期烤烟的总氮含量随着喷施浓度的增加呈现逐渐降低的趋势,而烤烟钾含量随着喷施浓度的增加呈现逐渐增加的趋势。随着生育期的延长,各处理烤烟中硒的积累速率在移栽后第75天达到最大值;随着土壤中硒含量的增加,烤烟中硒的积累速率呈现先升高后降低的趋势,当土壤中硒含量在5~12 mg/kg范围内,硒的积累速率最快。随着喷施浓度的增大,烤烟叶片中的硒含量也逐渐增加,并且各处理与对照之间的差异均在0.05水平上达到了显著。在烤烟10片叶喷施硒肥后,随着生育期的延长,烤烟中的硒逐步向上部叶和中部叶转移,从而不利于下部叶片中硒含量的积累;在15片叶喷施硒肥,可以适当增加烤烟所有叶片中的硒含量。因此,在烤烟15片叶喷施10μg/ml的硒溶液最有利于烤烟叶片中硒含量的积累。4、分析了土壤全硒含量与烤烟硒含量的特点。恩施烤烟硒含量平均值为(8.37±5.83)mg/kg,变幅为0.30~29.30 mg/kg,烤烟硒含量在不同部位间主要表现为X2F>C3F>B2F,在不同海拔间主要表现为中海拔(800~1200 m)>高海拔(≥1200 m)>低海拔(<800 m);恩施土壤全硒含量较高,平均值为(2.56±1.64)mg/kg,变幅为0.28~7.03 mg/kg,大多数土壤属于富硒和高硒土壤,其中34.44%属过量硒土壤,土壤全硒含量随着土层厚度的加深而降低,在不同海拔间与烤烟硒含量表现出相同的趋势;土壤全硒含量与烤烟硒含量存在极显著的正相关(相关系数为0.949),90个烤烟样品的硒含量( y|^ )与对应土壤样品全硒含量( x )建立的回归方程为y|^ = -0.1082x~3 +1.2494x~2-1.9628x+8.1647,经F测验回归方程达到了极显著水平。更多还原

【Abstract】 Through pot experiments in science and technology park of Henan University of Science and Technology in 2008, effects of different application amounts and methods of selenium on tobacco growth, physiological characteristics, and selenium content in tobacco leaves during growth periods were studied, and optimal selenium concentration for flue-cured tobacco growth was proposed. 90 soil samples and 72 tobacco samples including three cultivars of Yunyan87, Yunyan85 and K326 and three gradings of X2F, C3F and B2F were selected in Xuan’en county and Xianfeng county of Enshi autonomous of Hubei province. The distribution and relationship of selenium contents in both soil and flue-cured tobacco were analized. Main results were as follows.1. The effects of selenium on development of flue-cured tobacco（1） The suitable selenium content of soil promoted the flue-cured tobacco growth. When selenium content in the soil was at 0¹2mg/kg, it improved the tobacco height, stem perimeter, the maximum leaf area, the effective leaf quantity, and the dry matter accumulation of above- ground and below-ground at different degrees during different stages of flue-cured tobacco （ P<0.05）; when the selenium content in the soil was≥16 mg/kg, compared with the check, it decreased the tobacco height, stem perimeter, the maximum leaf area, the effective leaf quantity, and the dry matter accumulation of above-ground and below-ground during different stages of flue-cured tobacco. When the selenium content in the soil was at 0¹2mg/kg, the tobacco height, stem perimeter, and the dry matter accumulation of above-ground and below-ground in each period were the best. It showed that 8mg/kg selenium content in soil was the best to the growth of flue-cured tobacco. （2） The appropriate selenium spraying to the tobacco leaves promoted the growth of flue-cured tobacco. The effects of spraying selenium on tobacco leaves during the prophase and prometaphase were studied. The results showed that spraying 5μg/ml selenium solution in the prometaphase（ten leaves） increased the tobacco height, stem perimeter, the maximum leaf area, the effective leaf quantity, and the dry matter accumulation of above-ground and below-ground.2. The effects of selenium on chlorophyll and enzymatic activity of flue-cured tobacco（1） Chlorophyll and carotenoid content increased in the right concentration of selenium（0¹2mg/kg）; chlorophyll a, chlorophyll b, chlorophyll a+b and carotenoid began to decline when the selenium content≥16mg/kg in the soil, the tobacco leaves occurred deficient chlorosis when the selenium content reached 24mg/kg. The results of selenium solution spraying on tobacco indicated that: 2μg/ml of selenium solution sprayed in the prophase or 5μg/ml of selenium solution sprayed in the prometaphase was the most advantageous for chlorophyll and carotenoid content. The effect of spraying selenium to tobacco leaf was safer than applied sodium selenite to soil.（2） The results of adding selenium to soil experiment indicated that: the activities of POD and SOD increased at first, then decreased during different stages with the increasing of selenium concentration; when the selenium content≤8mg/kg in the soil, the content of MDA among different treatments decreased with the increasing of selenium concentration; and then, when the selenium content >8mg/kg in the soil, the MDA content increased; it showed that higher or lower selenium concentration was not suitable for growth of tobacco, also the appropriate selenium can alleviate membrane lipid peroxidation to a certain extent. The selenium could promoted the invertase activity. The invertase activity in tobacco leaves increased when selenium content in the soil at 2¹2 mg/kg, thus enhencing both carbohydrate metabolism and the amount of carbohydrates. Higher carbohydrate metabolism levels can both provide more carbon skeletons for thee growth of tobacco, the formation of organic compounds, and the transformation and utiliation of assimilate. The using intensity of photosynthate reduced under high selenium level and no selenium. NR activity showed 60d>45d>30d>75d in the different growth stages after treated with selenium. The activity of NR increased at first, then decreased with the increasing of selenium concentration, reached maximum at 8mg/kg respectively. Compared with the check, the activity of NR decreased when the selenium content≥16mg/kg in the soil.（3） The effect of the peroxydase activity （POD） didn’t be reflected in short time after spraying selenium to tobacco leaves, but the effect more and more obviously with the extension of time, the action of selenium to SOD was visible in short term, but weaken with the extension of time. The MDA content in the tobacco decreased obviously after spraying selenium, and it lasted a long period. Selenium fertilizer could improve the INV activity after spraying selenium from 2μg/ml to 10μg/ml, and the optimum content was 5μg/ml. INV activity of each treatment showed 75d>60d>45d after translating.3. The effects of selenium on the contents of potassium, total nitrogen and selenium in the growth of flue-cured tobaccoThe contents of total nitrogen and potassium of different tobacco treatments reduced gradually with the growing period extended. With the increasing of soil selenium content, the content of total nitrogen decreased first and then increased in every period while the content of potassium increased first and then decreased. Low Se concentratation（0¹2mg/kg）could reduce the total nitrogen content and increase the potassium content in the development of flue-cured tobacco. The total nitrogen content reached the minimum while potassium content reached the maximum in every period when the concentration of the soil selenium content was 8mg/kg. The nitrogen content of flue-cured tobacco reduced gradually while the potassium content increased gradually with the increase of spray concentration in every period after spraying selenium.As growing period extended, the accumulation rate of selenium in different treatments reached the maximum at seventy-fifth day after transplanting. The accumulation rate of selenium of flue-cured tobacco increased first and then decreased with the increasing of soil selenium content. The accumulation rate of selenium was fastest when soil selenium content at 5¹2mg/kg. With the increasing of spraying concentration, the selenium content in flue-cured tobacco leaves increased gradually and the differences between treatments and contrasts were significant（P<0.05）. After spraying selenium at early vigorous growth stages（10 pieces of leaves）, the selenium of flue-cured tobacco was gradually translocated to upper and middle leaves as the growing period extended, thereby being unfavorable to selenium accumulation in the lower leaves. Spraying selenium at vigorous growth stages（15 pieces of leaves） could appropriately increase the selenium content in all tobacco leaves. Therefore, spraying selenium solution of 10μg/ml was the best for the accumulation of selenium in flue-cured tobacco leaves.4. Relationships between the soil selenium contents and the selenium content in flue-cured tobacco leaves were analyzed. The results indicated that: （1） The selenium contents in flue-cured tobacco leaves in Enshi were high,ranging from 0.30 to 29.30 mg·kg^-1 with the mean of（8.37±5.83） mg·kg^-1. The content of selenium in flue-cured tobacco among different positions was X2F>C3F>B2F, among different altitudes was medium altitude（800m¹200m） >high altitude （≥1200m） >low altitude（<800m）. （2） The soil selenium contents in Enshi tobacco-growing area were high,ranging from 0.28 to 7.03 mg·kg^-1 with the mean of（2.56±1.64） mg·kg^-1.Most of the soil was selenium-rich and high-selenium soil, and 34.44% soils were excessive-selenium soil, with the deepening of the soil thickness, soil selenium contents become lower and lower, and showed the same trend with the selenium content of flue-cured tobacco at different altitudes. （3） There was significantly positively correlation between soil selenium content and selenium content of flue-cured tobacco（correlation coefficient was 0.949）. Based on the correlation analysis , the regression equation ,y|^ = -0.1082x³ +1.2494x²-1.9628x+8.1647 was established between soil available selenium and the selenium contents in flue-cured tobacco leaves for 72 samples. Regression equation reached a significant level by F-test.更多还原