The critical concentration of mannitol stress is 0 . 8 - 0 . 9mol - l - 1 . the maximal level of aba accumulation is attached after 5 hours " treat with 0 . 9mol - l - 1 mannitol solution . cell wall plays important roles in tobacco cells perception to osmotic stress 渗透胁迫诱导aba积累的水平与胁迫处理的浓度和时间相关，胁迫处理的有临界浓度为0 . 8 ? 0 . 9mol ? l ~ ( - 1 ) ， aba积累水平在胁迫处理5小时后达到最大。
