在人工模拟的寒害条件下，对寒害胁迫0、1、2和3 d以及恢复培养1、2、3 d及2个月晴冷型（昼温约25 ℃、夜温6 ℃，全自然光）和阴冷型（昼温约25 ℃、夜温6 ℃，遮光率50％）寒害处理组橡胶树〔Hevea brasiliensis （Willd. ex A. Juss.） Müll. Arg.〕品种‘RRIM600’、‘云研73-46’（‘Yunyan 73-46’）、‘PR107’和‘93-114’叶片的耐寒性指标（包括光合气体交换参数和部分生理生化指标）进行了比较；在此基础上，对所有耐寒性指标进行了主成分分析，并对各品种的耐寒性进行了综合评价。结果表明：总体来看，寒害胁迫3 d和恢复培养3 d，4个品种的净光合速率（Pn）、蒸腾速率（Tr）和气孔导度（Gs）显著低于寒害胁迫前（寒害胁迫0 d）水平，而胞间CO2浓度（Ci）在寒害胁迫3 d显著高于寒害胁迫前水平并在恢复培养3 d恢复至寒害胁迫前水平；恢复培养2个月，4个品种的Pn、Tr和Gs值恢复至寒害胁迫前水平，而Ci值则高于或显著高于寒害胁迫前水平。4个品种的丙二醛（MDA）含量在寒害胁迫3 d高于寒害胁迫前水平；品种‘RRIM600’和‘云研73-46’的MDA含量在恢复培养3 d显著高于寒害胁迫前水平、在恢复培养2个月恢复至寒害胁迫前水平，而品种‘PR107’和‘93-114’的MDA含量却在恢复培养3 d和2个月显著低于寒害胁迫前水平。寒害胁迫3 d及恢复培养3 d和2个月，4个品种的质膜相对透性显著高于寒害胁迫前水平。实验期间，4个品种的可溶性糖、蔗糖、脯氨酸和可溶性蛋白质含量呈波动变化。主成分分析结果表明：前3个主成分的特征值均大于1，累计贡献率为7130％，说明这3个主成分可反映橡胶树所有指标的绝大部分信息。根据综合得分，在晴冷型寒害胁迫条件下，品种‘RRIM600’的耐寒性最强、品种‘PR107’的耐寒性最弱，而在阴冷型寒害胁迫条件下恰好相反。研究结果显示在实际生产中应根据各橡胶树品种的耐寒性选择合适种植地。

Under artificial simulated chilling stress condition， leaf cold tolerance indexes （including photosynthetic gas exchange parameters and some physiological and biochemical indexes） of cultivar ‘RRIM600’， ‘Yunyan 73-46’， ‘PR107’， and ‘93-114’ of Hevea brasiliensis （Willd. ex A. Juss.） Müll. Arg. in sunny chilling injury （day temperature of about 25 ℃， night temperature of 6 ℃， and fully natural light） and cloudy chilling injury （day temperature of about 25 ℃， night temperature of 6 ℃， and shading rate of 50％） treatment groups under chilling stress for 0， 1， 2， and 3 d， and recovery culturing for 1， 2， 3 d， and 2 months were compared. On the basis， principal component analysis on all cold tolerance indexes was conducted， and cold tolerance of each cultivar was evaluated comprehensively. The results show that in general， net photosynthetic rate （Pn）， transpiration rate （Tr）， and stomatal conductance （Gs） of 4 cultivars under chilling stress for 3 d and recovery culturing for 3 d are significantly lower than the levels before chilling stress （chilling stress for 0 d）， while intercellular CO₂ concentration （Ci） under chilling stress for 3 d is significantly higher than the level before chilling stress and restores to the level before chilling stress under recovery culturing for 3 d. Under recovery culturing for 2 months， Pn， Tr， and Gs values of 4 cultivars all restore to the levels before chilling stress， while Ci value is higher or significantly higher than the level before chilling stress. Malondialdehyde （MDA） content of 4 cultivars under chilling stress for 3 d is higher than the level before chilling stress； MDA content of cultivar ‘RRIM600’ and ‘Yunyan 73-46’ under recovery culturing for 3 d is significantly higher than the level before chilling stress， and restores to the level before chilling stress under recovery culturing for 2 months， but that of cultivar ‘PR107’ and ‘93-114’ under recovery culturing for 3 d and 2 months is significantly lower than the level before chilling stress. Under chilling stress for 3 d and recovery culturing for 3 d and 2 months， relative permeability of plasma membrane of 4 cultivars is significantly higher than the level before chilling stress. During the experimental period， contents of soluble sugar， sucrose， proline， and soluble protein of 4 cultivars show a fluctuation change. Principal component analysis results show that eigenvalues of the first three principal components are all greater than 1， and their cumulative contribution rate is 71.30％， indicating that the first three principal components can reflect most informations of all indexes of H. brasiliensis. According to comprehensive score， under sunny chilling injury stress condition， cold tolerance of cultivar ‘RRIM600’ is the strongest， and that of cultivar ‘PR107’ is the weakest， while it is opposite under cloudy chilling injury stress condition. It is suggested that suitable planting site should be chosen according to cold tolerance of each cultivar of H. brasiliensis in actual production.