ABA和PP333对国兰低温胁迫及恢复中光合作用和叶绿素荧光参数的影响

为探讨植物生长调节剂ABA和PP333对国兰低温胁迫下抗寒性的影响,以春兰名品‘宋梅’为试材,采用20 mg/L ABA和300 mg/L PP333对‘宋梅’幼苗叶片进行叶面喷施和灌根处理,于光照培养箱昼温/夜温=（5±0.5）℃/（0±0.5）℃]中进行低温胁迫9天,然后转入正常条件昼温/夜温=（22±0.5）℃/（1 5±0.5）℃]恢复12天,研究不同低温处理及恢复时间对国兰光合作用和叶绿素荧光参数的影响.结果表明：低温导致春兰幼苗叶片的叶绿素含量、叶片净光合速率（Pn）、气孔导度（Gs）、气孔限制值（Ls）、PSⅡ最大光化学效率（Fv/ Fm）、光化学猝灭系数（qP）、光合电子传递量子效率（ΦPSⅡ）、光适应下最大光化学效率（FV＇/Fm＇）、光合电子传递速率（ETR）和光化学耗散能量（Prate）下降,胞间CO2浓度（Ci）、初始荧光（F0）和天线热耗散速率（Drate）则逐步上升,经ABA和PP333处理的植株指标波动幅度低于清水处理的植株,胁迫解除后能迅速恢复到对照水平,说明低温胁迫直接损伤光合机构使PSⅡ反应中心失活,而ABA和PP333可缓解PSⅡ反应中心受到的伤害,维持较高的光能捕捉能力和同化率,保证春兰幼苗叶片的光合作用能力.

Effect of ABA and PP333 on the photosynthesis and chlorophyll fluorescence param eters of Cymbidium seedlings which in low temperature stress and its recovery

In order to research the effect of ABA and PP333 on frost resistance of Cymbidium seedlings, the Cymbidium goeringii ＇Songmei＇ was respectively treated with 20 mg/L ABA and 300 mg/L PP333, and then transferred to low temperature （5±0.5）℃/（0±0.5）℃）] for 9 days and transferred to normal condition（22±0.5）℃/ （15 ± 0.5）℃ ] for 12 days. The results showed that： With the low temperature stress, the chlorophyll concentration, the net photosynthetic rate （Pn）, the stomatal conductance（Gs）, the stomatal limitation（Ls）, the PS Ⅱ maximal photochemical efficiency（Fv/Fm）, the photochemical quenching coefficient（qP）, the quantum yield of PS 11 electron transport（ΦPSⅡ）, the maximal photochemical efficiency of PS Ⅱ （Fv＇ /Fm＇ ）, the apparent photosynthetic electron transfer rate（ETR） and the photochemistry react rate （Prate） decreased while the intercellular C02 concentration（C1）, the initial fluorescence（F0） and the hot dissipation of antenna（Drate） increased. The index volatility of the Cymbidium goeringii ＇Songmei＇ which was treated with ABA and PP333 was below that of the water and recovered quickly after the release of low temperature stress. These results suggested that the low temperature stress had caused damage to the PS Ⅱ reaction center, and the ABA and PP333 could ease the hurt of the PSⅡ reaction center and maintain both the primary capture capacity and assimilation efficiency of light energy, and the final ensure the photosynthesis capacity of Cymbidium seedlinzs.