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以2年生凹叶厚朴幼苗为试材,研究了在不同低温胁迫(-5、0、5、10、15℃,以25℃为对照)下凹叶厚朴生理指标和光合特性的变化。结果表明:随着胁迫温度降低,凹叶厚朴幼苗叶绿素含量下降,净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)逐步降低,光合PSⅡ最大光化学效率(Fv/Fm)、潜在光化学效率(Fv/Fo)、表观电子传递速率(ETR)、光合量子产额(Yield)、光化学淬灭系数(qP)总体呈现递减趋势,而胞间CO2浓度(Ci)、丙二醛(MDA)含量、细胞质膜透性、非光化学淬灭系数(NPQ)呈上升趋势,质膜在-5℃时受损最严重,大量离子外渗。低温使叶绿素显著降低,PSⅡ反应中心受损,对凹叶厚朴幼苗产生显著光抑制,导致光合作用能力降低。
Taking 2-year-old Osmanthus fragrans as seed material, the changes of physiological indexes and photosynthetic characteristics of Magnolia castelba under different low temperature stress (-5,0,5,10,15 ℃, 25 ℃) were studied. The results showed that chlorophyll content of Magnolia bocedonii decreased, photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr) decreased gradually, photosynthetic maximum photochemical efficiency of PSⅡ (Fv / Fm) Fv / Fo, ETR, Yield and photochemical quenching (qP) showed a decreasing trend, while intercellular CO2 concentration (Ci), malondialdehyde MDA content, plasma membrane permeability and non-photochemical quenching coefficient (NPQ) showed an upward trend. The plasma membrane damaged most severely at -5 ℃ and a large amount of ion extravasation. The chlorophyll content decreased significantly at low temperature, and the PS Ⅱ reaction center was impaired, which significantly inhibited the photosynthesis of Magnolia bwardscens seedlings.