育苗阶段不同氮浓度对烟苗部分生理生化指标的影响

以红花大金元烤烟品种为材料，研究了育苗阶段不同氮浓度营养液即50、150、250、350、450、550mg/kg对成苗时烟苗农艺性状、根系活力、脯氨酸含量以及移栽后30d时体内多酚氧化酶、过氧化物酶、过氧化氢酶等活性的影响。试验结果表明：(1)当氮浓度在50~450mg/kg时，成苗时烟苗的干、鲜重随之增加，而氮浓度到550mg/kg时，烟苗的干、鲜重开始减少，说明育苗烟苗营养液浓度过低、过高均不利于烟苗的干物质的积累；(2)育苗阶段不同氮浓度营养液处理烟苗的活跃吸收面积存在极显著差异，其中以150、250mg/kg的处理为最大；(3)随着氮浓度提高，移栽时烟株体内的脯氨酸含量随之下降；(4)在移栽后30d，氮浓度为150mg/kg的处理烟株体内多酚氧化酶、过氧化物酶、过氧化氢酶活性最高，且随着氮浓度的增加而随之减少，蛋白质含量则随着氮浓度的增加而增加。综合而言，育苗阶段营养液中的氮浓度为150、250mg/kg时有利于培育抗性较强的红大品种烤烟烟苗。

Influence of the Different Nitrogen Concentration in Float System on Some Physiological Characters of Flue-cured Tobacco

The test was conducted to study the influence of the different nitrogen concentration in float system on some agronomical and physiological characters of flue-cured tobacco plant at transplanting and 30 days after transplanting respectively.The results showed that:(1) The dry matter accumulation of tobacco seedlings were improved when the nitrogen concentration was increased from 50 to 450 mg/kg in float system,while that of the seedlings treated with 550 mg/kg was decreased;(2) Nitrogen concentration in float system had great influence on root activity.Root activity of the seedlings treated with 150 or 250 mg/kg were higher than others;(3) Proline content in tobacco seedlings was decreased at the time for transplanting when the nitrogen concentration was increased in float system;(4) The activity of peroxidase,catalase and polyphenoloxidase were observed highest in plants at 30 days after transplanting which were nursed in float system with nitrogen concentration at 150 mg/kg,while those of tobacco seedlings treated with more nitrogen in nutrition solution deceased.And it was reverse for the content of protein.In a word,it could be considered that the ability of resistance of HD plant should be better if the seedlings were nursed in float system with nitrogen concentration at 150 to 250mg/kg.