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研究了夜间低温对两个芒果(Mangifera indica)品种翡翠芒(Khieo Sawoei)和四季芒(Choke Anand)光合生理的影响。两个芒果品种的幼苗盆栽于全光和50%相对光强下一年。在第二年的冬季,连续7天晚上将芒果幼苗移到4℃的冷库中,白天保持原条件。于低温处理前、处理期间和结束低温处理后10天中测定芒果幼苗的光合生理特征。结果表明,夜间低温导致两个芒果品种的净光合速率、气孔导度和光系统II的最大光化学效率(Fv/Fm)降低、非光化学猝灭(NPQ)上升。夜间低温对生长在全光下的芒果幼苗光合作用的抑制比50%光下的更重。翡翠芒的Fv/Fm比四季芒下降的更多,但后者的NPQ上升更多。夜间低温还导致两种光下芒果幼苗叶片的叶绿素含量下降,类胡萝卜素/叶绿素比值、丙二醛含量、膜的透性和可溶性化合物(可溶性总糖和脯氨酸)上升。解除低温胁迫后,四季芒Fv/Fm的恢复比翡翠芒的快。解除低温胁迫7天后二者的Fv/Fm能完全恢复。上述结果表明,翡翠芒对低温更敏感,遮荫可以明显缓解两个芒果品种低温引起的光抑制。
The effects of nocturnal low temperature on the photosynthetic physiology of two mangifera indica cultivars, Khieo Sawoei and Choke Anand, were studied. Seedlings of two mango cultivars were potted at full light and 50% relative light intensity for one year. In the second year of winter, mango seedlings were moved to cold storage at 4 ° C for seven days in the evening, maintaining the original conditions during the day. Photosynthetic physiological characteristics of mango seedlings were determined before, during and 10 days after the end of low temperature treatment. The results showed that the nighttime hypothermia resulted in the decrease of net photosynthetic rate, stomatal conductance and maximum photochemical efficiency (Fv / Fm) of photosystem II and the increase of non-photochemical quenching (NPQ) in two mango cultivars. Night nocturnal depression inhibited the photosynthesis of mango seedlings under full light more than that under 50% light. Emerald Mount’s Fv / Fm dropped more than the Four Seasons, but the latter NPQ rose more. Chilling at night also led to a decrease in chlorophyll content, carotenoid / chlorophyll ratio, malondialdehyde content, membrane permeability and soluble compounds (soluble total sugar and proline) in mango seedling leaves under both light conditions. After relieving low temperature stress, the Fv / Fm of Four Seasons Mount was recovered faster than that of Emerald Mount. Fv / Fm recovered completely after 7 days of cold stress relief. The above results show that Emerald mulberry is more sensitive to low temperature, shade can significantly alleviate the photoperiod induced by low temperature of two mango varieties.