中文摘要：

以6个北疆棉花主栽品种（品系）为试材,对其进行5℃的低温处理,25℃为对照,研究其幼苗光合特性的变化。结果表明：低温处理后,棉花幼苗叶片的净光合速率（Pn）、蒸腾速率（Tr）、气孔导度（Gs）均比对照低,而叶片细胞间隙CO2浓度（Ci）的变化在不同品种中表现差异,新陆早13、297-5和4723下降,而81-3、新陆早36和134-1的变化呈上升趋势。此外,结果还显示,低温处理对棉花幼苗叶片光合参数（Pn、Ci、Gs、Tr）的影响在品种间存在显著差异。因此,Pn、Ci、Gs、Tr可以作为鉴定棉花抗寒性能的指标。

英文摘要：

A research into the effects of low temperature stress on Cotton seedlings photosynthesis was performed and while the temperature condition was designed to 5 ℃ and 25 ℃ as control.The results showed that the net photosynthetic rate（Pn）,stomatal conductance（Gs） and transpiration rate（Tr） decreased significantly,while intercellular CO2 concentration（Ci） increased at species of xinluzao13,Xinluzao 297-5,Xinluzao 4723 and was decreased at species of Xinluzao 81-3,Xinluzao36 and Xinluzao 134-1.Pn,Ci,Gs,Tr were obviously different at different cotton cultivars.These results suggested that Pn,Ci,Gs,Tr can be used to identify the resistance on different breeds of cotton.