中文摘要：

以棉纤维品质差异较大的2个品种为材料,于2005-2006年在江苏南京设置不同播期试验,研究棉铃发育期不同温度对棉铃对位叶保护酶活性及C、N代谢等生理特性的影响及其与铃重形成的关系.结果表明：棉铃发育期日平均温度在23.1℃-24.9℃时棉铃对位叶的可溶性蛋白含量和内源保护酶活性较高,膜质过氧化程度轻,C、N生理活性均强,C/N协调,棉铃平均增重速度较高,棉铃快速增重期延长,易形成大铃;≥27.0℃时可溶性蛋白含量和内源保护酶活性较低、膜脂过氧化程度严重、N生理活性较弱、C/N高,铃重平均增重速度虽高,但快速增重期短,不利于提高铃重;≤20.7℃时可溶性蛋白含量下降快,内源保护酶活性较高,但酶活性下降时间早、速度快,膜脂过氧化程度也严重,可溶性糖转运率低且在对位叶内积累,N生理活性高,C/N低,铃重快速增重期虽长,但平均增重速率低,最终铃重下降.低温下科棉1号的对位叶生理活性比美棉33B强,铃重也较高.可见,棉铃对位叶保护酶活性高,C/N协调能提高铃重,而适宜的铃期日均温可以提高棉铃对位叶的生理特性.

英文摘要：

To study the effect of temperature on physiological characteristics in leaf subtending boll （LSB） and boll weight forming,we were carried out field experiments with different genotype cultivars by setting different cotton seeding dates in 2005 and 2006 in Nanjing,Jiangsu province. The results showed that,when the daily mean temperature （DMT） during boll maturation period was in the range of 23.1 ℃ to 24.9℃ ,the LSB had higher soluble protein content, higher physiological activities and longer duration of function. That mainly present as higher activities of internal protective enzymes,lower MDA content,and more ideal C/N ratio,and these characters were helpful to increase the average velocity and prolong the time for rapid increasing in boll developing, and to form higher boll weight. When the the DMT during boll maturation period was above 27.0℃, the physiological activities in LSB decreased, but C/N ratios increased, which resulted in the increase of average velocity,the shorter duration time for rapid increasing in boll developing,and the lower boll weight in some extent. When the DMT during boll maturation period was below 20.7 ℃, the LSB had higher physiological activities at the prophase, but it had faster velocity of physiological activities de-creasing during middle and later of boll development and lower C/N ratios, these led to longer duration time for rapid increasing and lower average velocity in boll developing,resuliting in lower boll weight. Un- der the low temperature conditions in this study, the physiological activities in LSB for Kemian 1 weg higher than that for NuCOTN33B,and the difference of boll weight between the two cultivars showeu simi- lar trends. From above results, we suggested that, under our experiment conditions, higher activities of internal protective enzymes and more ideal C/N ratio in LSB might be important reasons causing the difference in boll weight. Moreover the DMT during boll maturation and the cultivar genectic background also significantly influence the