Abstract: In order to investigate the physiological response mechanism of tobacco seedlings to deacclimation duration, flue-cured tobacco variety K326 was used as test material, water cultivation in an artificial climate chamber was carried out. An acclimation model including acclimation-deacclimation-reacclimation was designed. Four deacclimation treatments were set up, including 0（CK）、24（D1）、48（D2）、72（D3）h cultured in Hoagland solution, and their acclimation and reacclimation treatment were the same, with common conditions (in Hoagland solution) during the whole period  as treatment N.  Physiological indexes such as photosynthetic pigments contents, root activities, antioxidant enzyme activities, osmoregulation substance contents and malondialdehyde (MDA) of tobacco seedlings were investigated. Results suggested that photosynthetic pigments contents, root activities and enzyme activities during deacclimation showed the trend of first up and then down, with the increasing of deacclimation duration; and these indexes achieved the highest level in D2 treatment; MDA content during deacclimation showed the trend of first down and then up, and achieved the lowest level in D2 treatment. The index values in D2 treatment were similar to those in treatment N. The antioxidant abilities of the tobacco seedlings were improved after deacclimation for 48 h using the acclimation-deacclimation-reacclimation model, along with drought resistance acquiring.

Key words: deacclimation, drought stress, tobacco seedling

摘要： 为探究烟草幼苗对脱驯化时长的生理响应机制，以烤烟品种‘K326’为供试材料，于人工气候室以水培法进行幼苗培养，驯化过程包括驯化—脱驯化—再驯化三个阶段，设置0（CK）、24（D1）、48（D2）、72（D3） h 4个脱驯化时间处理，4个处理的驯化和再驯化处理保持一致，以正常培养作为处理N，测定各处理烟草幼苗的光合色素含量、根系活力、抗氧化酶活性、渗透调节物质及丙二醛（malondialdehyde，MDA）含量等生理指标。结果表明，脱驯化时长能够影响烟草幼苗抗逆性。烟草植株光合色素含量、根系活力、抗氧化酶活性在随着脱驯化时长增加均呈现先升后降的趋势，在D2处理中最高，MDA含量则呈现先降后升的趋势，在D2处理中达到最低。且D2处理各指标水平接近N处理。在整个驯化—脱驯化—再驯化过程中，脱驯化48 h的烟草植株抗氧化能力升高，植株渗透调节相对稳定，在脱驯化过程中获得一定的耐受性。

关键词: 脱驯化, 干旱胁迫, 烟草幼苗