[Objective]The present experiment was carried out to study the effects of atmospheric CO2 concentrations on roots characteristics and NRA in leaves of two rape cultivars. [Method ]Two nitrogen efficiency types of rape cultivars (X-2 and X-6) were tested by sand culture with Hoagland complete nutrient solution under greenhouse conditions with two CO2 concentrations (low concentration: nature, control, and high concentration: 800±20 μmol/mol) to study effects of different atmospheric CO2 concentrations on root characteristics and NRA in leaves of rape. [Result]For rap cultivar X-2. at bolting stage, the 1st lateral roots, root volume and root diameter under high C02 concentration increased by 0.43, 34.33 and 16.61% from control, respectively, while total root length was 33.01% less than control; at flowering stage, root volume, root diameter, total root length and root/shoot under high CO2 concentration increased by 18.77, 9.68, 3.88 and 3.57%, respectively compared to control. For cultivar X-6, at bolting stage, the 1" lateral roots, root volume, roots diameter and total length under high CO2 concentration increased by 19.58, 9.17, 9.87 and 21.08%, respectively; at flowering stage, root volume, roots diameter and root/shoot increased by 1.95, 12.70 and 10.52%, respectively; while the Ist lateral roots and root diameter decreased by 6.80 and 23.37%, respectively. Compared to natural CO2 concentration, the root activity of X-2 under high CO2 concentration increased by 83.40 and 18.67% at bolting and flowering stage, resepectively, while that of X-6 decreased by 12.50 and 380.13%, respectively, NRA of X-2 and X-6 decreased by 12.65 and 37.71% at bolting stage,while increased 18.59 and 10.67% at flowering stage, respectively. [Conclusion]High-nitrogen efficiency rape cultivar X-2 showed better root characteristics than low -nitrogen efficiency cultivar X-6 regardless of atmospheric CO2 concentration and growth stage. High atmospheric CO2 concentration was beneficial to improve root characteristics and physiological activity at bolting and flowering stage. No significant effect rule of high CO2 concentration on X-6 was found.%[目的]探讨不同CO2浓度对油菜根系特性和叶片硝酸还原酶的影响,为确定环境CO2浓度升高对油菜生理及形态的影响提供参考.[方法]不同CO2浓度温棚环境下,采用Hoagland完全营养液砂培法,设CO2浓度、油菜品种两个因子,探讨不同CO2浓度对油菜根系性状和生理特性的影响.[结果]相对于正常CO2浓度(CK),高CO2浓度处理的油菜品种X-2在抽薹期的一级侧根数、根体积、根茎粗分别增加0.43％、34.33％和16.61％,总根长降低33.01％；在盛花期,根体积、根茎粗、总根长和根冠比分别增加18.77％、9.68％、3.88％和3.57％.X-6高CO2浓度处理在抽薹期的一级侧根数、根体积、根茎粗、总根长分别增加19.58％、9.17％、9.87％和21.08％;盛花期根体积、根茎粗和根冠比分别增加1.95％、12.70％和10.52％,一级侧根数和总根长分别降低6.80％.23.37％.与对照相比,高CO2浓度条件下,X-6的根系活跃吸收面积和总吸收面积在抽薹期和盛花期表现为先降低后增加的趋势,X-2则表现为先增加后降低的趋势；抽薹和盛花期X-2根系活力分别增加83.40％和18.67％,而X-6根系活力较对照分别降低12.50％和380.13％；X-2和X-6在抽薹期的NR活性分别降低12.65％和37.71％,在盛花期则分别增高18.59％和10.67％.[结论]不同生育期不同浓度CO2条件下,品种X-2的根系性状表现相对优于X-6,CO2浓度升高利于改善X-2抽薹期和盛花期的根系性状和生理活性;高CO2浓度对不同时期X-6的根系性状和生理活件的影响无明显规律.
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