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以烤烟品种“龙江911”为试验材料,研究了干旱及复水过程中外源茉莉酸甲酯(Me-JA)对移栽后烤烟幼苗叶绿素含量和叶绿素荧光特性的影响.结果表明:干旱下烤烟幼苗叶绿素含量、PSⅡ反应中心完全关闭时荧光产量(Fm)、PSⅡ潜在活性(Fv/Fo)、最大光化学效率(Fv/Fm)、实际光化学效率(ФPSⅡ)、表观电子传递速率(ETR)和光化学猝灭系数(qP)下降,而初始荧光(Fo)和非光化学猝灭系数(qN)升高,0.2和0.5mmol.L-1的外源MeJA明显减缓了干旱下烤烟幼苗Fv/Fm、Fv/Fo、ФPSⅡ、ETR、qP的下降和qN的上升,而1.0mmol.L-1MeJA效果不明显.复水后,烤烟幼苗各项叶绿素荧光指标均有明显恢复,并且MeJA处理后的幼苗恢复更明显.表明外源MeJA减轻了干旱胁迫下烤烟叶片叶绿素的分解,对PSII反应中心起到一定的保护作用,提高了电子传递速率,降低了干旱胁迫对烤烟幼苗的伤害,并且复水后叶绿素含量和叶绿素荧光参数能迅速恢复,从而保证了经干旱胁迫后烤烟幼苗能迅速缓苗.
Effects of Me-JA on chlorophyll content and chlorophyll fluorescence of flue-cured tobacco seedlings after drought and rehydration were studied using a flue-cured tobacco variety “Longjiang 911” as experimental material.The results showed that: Fv, Fo, Fv / Fm, actual photochemical efficiency (ФPSⅡ), apparent electron transport rate (Fv / Fo), photosynthetic rate ETR and qP, while the initial fluorescence (Fo) and non-photochemical quenching coefficient (qN) increased. Exogenous MeJA at 0.2 and 0.5mmol.L-1 significantly reduced Fv / Fm, Fv / Fo, ФPSⅡ, ETR, qP and qN, while the effect of 1.0mmol.L-1MeJA was not obvious.After rewatering, the chlorophyll fluorescence parameters of flue-cured tobacco seedlings recovered obviously, and after MeJA treatment , Suggesting that exogenous MeJA can reduce the decomposition of chlorophyll in flue-cured tobacco leaves under drought stress, which may play a protective role in the PSII reaction center, improve the electron transfer rate and reduce the damage of tobacco seedlings under drought stress, Water chlorophyll content and chlorophyll fluorescence Light parameters can be quickly restored, thus ensuring the drought-resistant flue-cured tobacco seedlings can quickly Huanmiao.