以栽植于亚热带的常绿阔叶植物榕树（Ficus microcarpa Linn. f.）、广玉兰（Magnolia grandiflora Linn.）和红叶石楠（Photinia × fraseri Dress.）为研究对象，比较了冬季低温胁迫下3种植物阳生叶和阴生叶的叶绿素荧光参数及其分布特征，并探讨了冬季低温对不同耐冷性植物叶片光抑制的影响。结果显示：榕树阳生叶和阴生叶的PSⅡ最大光化学效率（Fv/Fm）均显著（p＜0.05）低于广玉兰和红叶石楠，但广玉兰和红叶石楠之间阳生叶和阴生叶的Fv/Fm差异不显著。3种植物阴生叶的调节性能量耗散的量子产额〔Y(NPQ)〕和非光化学猝灭系数（NPQ）均较高，且轻度光抑制区和健康区的总比例达96%以上。3种植物阳生叶的Fv/Fm显著低于阴生叶，其中榕树阳生叶受到严重光抑制，其无光合活性区和重度光抑制区总比例达93.88%，远高于广玉兰（20.53%）和红叶石楠（8.22%）。在冬季低温下，红叶石楠阳生叶的有效光化学效率〔Y(Ⅱ)〕和光化学猝灭系数（qP）较高，且Y(NPQ)和NPQ相对较高，其中，阳生叶的Y(Ⅱ)和qP分别为0.196和0.481，显著高于榕树和广玉兰；广玉兰阳生叶的Y(Ⅱ)和qP较低，但Y(NPQ)和NPQ较高；榕树阳生叶的Y(Ⅱ)、qP、Y(NPQ)和NPQ均处于较低水平，分别为0.152、0.159、0.333和0.841。综合分析结果表明：冬季低温导致3种植物叶片发生光抑制，阳生叶的光抑制程度更大。榕树叶片光化学反应和热耗散能力均较低，因而对冬季低温更敏感。广玉兰主要通过维持较高的热耗散能力以防御低温光抑制，而红叶石楠则通过维持相对较高的光化学反应和热耗散能力以防御低温光抑制。

Taking the evergreen broad-leaved plants Ficus microcarpa Linn. f., Magnolia grandiflora Linn., and Photinia × fraseri Dress. planted in subtropics as research objects, the chlorophyll fluorescence parameters and their distribution characteristics of sun leaves and shade leaves of the three species under low temperature stress in winter were compared, and the effects of low temperature in winter on photoinhibition in leaves of plants with different cold tolerance were investigated. The results show that the maximum photochemical efficiency of PSⅡ (Fv/Fm) in sun leaves and shade leaves of F. microcarpa are significantly (p＜0.05) lower than those of M. grandiflora and P. × fraseri, but there is no significant difference in Fv/Fm in sun leaves and shade leaves between M. grandiflora and P. × fraseri. The regulatory energy dissipation quantum yield 〔Y(NPQ)〕 and nonphotochemical quenching coefficient (NPQ) in shade leaves of the three species are all high, the total proportion of mild light suppression area and healthy area is greater than 96%. Fv/Fm in sun leaves of the three species are significantly lower than those in shade leaves, in which, the sun leaves of F. macrocarpa are under severe photoinhibition, and the total proportion of its non-photosynthetic activity area and severe photoinhibition area is 93.88%, which is much higher than those of M. grandiflora (20.53%) and P. × fraseri (8.22%). Under low temperature in winter, the effective photochemical efficiency 〔Y(Ⅱ)〕 and photochemical quenching coefficient (qP) in sun leaves of P. × fraseri are high, and its Y(NPQ) and NPQ values are relatively high; in which, Y(Ⅱ) and qP in sun leaves are 0.196 and 0.481, respectively, which are significantly higher than those of F. microcarpa and M. grandiflora. Y(Ⅱ) and qP in sun leaves of M. grandiflora are low, but Y(NPQ) and NPQ are high. Y(Ⅱ), qP, Y(NPQ), and NPQ in sun leaves of F. microcarpa are all low, which are 0.152, 0.159, 0.333, and 0.841, respectively. The comprehensive analysis result shows that low temperature in winter induces photoinhibition of leaves of the three species, and photoinhibition of sun leaves is aggravated. The photochemical reaction and thermal dissipation capacity are both low in leaves of F. macrocarpa, therefore, it is more sensitive to low temperature in winter. M. grandiflora defends against photoinhibition under low temperature by maintaining high thermal dissipation capacity, while P. × fraseri defends against photoinhibition under low temperature by maintaining high photochemical reaction and thermal energy dissipation capacity.