Abstract: In the conditions of floating seedling system, this paper studied the seedling quality changes of tobacco with spraying paclobutrazol in the period of three and a primary leaves in South Anhui. The results showed that: ① Spraying paclobutrazol had significant affection on the agronomic traits, root activity, chlorophyll content, NR activity, matters of anti-adversity and MDA content of tobacco seedlings, the effect was related to different concentration. ② Compared with CK, after sprayed paclobutrazol with 100 mg/kg and 125 mg/kg, the height of stem decreased by 45.25% and 52.94%, the dry weight of stem and leaf decreased by 37.02% and 39.45%, the diameter increased by 19.42% and 27.30%, dry weight of root increased by 19.53% and 28.62%, root activity increased by 10.59% and 14.32%, the SPAD content of chlorophyll increased by 18.12% and 27.68%, the NR activity increased by 54.51% and 73.17%, the soluble sugar content increased by 24.66% and 40.54%, the soluble protein content increased by 24.26% and 28.82%, the free proline content increased by 8.47% and 10.77%, the MDA content decreased by 7.54% and 8.70%, seedling characteristics was improved and the effect was better.

Key words: paclobutrazol, tobacco seedling, physiological characteristics, floating seedling

摘要： 在皖南烟区漂浮育苗模式下，对烟苗3叶1心期叶面喷施不同浓度多效唑,研究烤烟苗期喷施多效唑对烟苗生长及生理特性的影响，结果表明：①喷施多效唑对烟苗农艺性状、根系活力、叶绿素含量、NR活性、抗逆性物质及MDA含量有显著影响，影响幅度与喷施浓度有关；②喷施100 mg/kg、125 mg/kg多效唑，相较CK，烟苗茎高降低45.25%和52.94%，茎叶干重降低37.02%和39.45%，直径增加19.42%和27.30%，根干重增加19.53%和28.62%，根系活力提高10.59%和14.32%，叶绿素含量SPAD值提高18.12%和27.68%，NR活性提高54.51%和73.17%，可溶性糖含量提高24.66%和40.54%，可溶性蛋白含量提高24.26%和28.82%，游离脯氨酸含量提高8.47%和10.77%，MDA含量降低7.54%和8.70%，烟苗综合特性较优。

关键词: 多效唑, 烟苗, 生理特性, 漂浮育苗