中文摘要：

以巴西固氮甘蔗品种‘B1’、‘B8’和广西主栽甘蔗品种‘ROC22’和‘ROC16’为材料，通过桶栽砂培方法，研究不同品种甘蔗及接种固氮菌R16SH后不同生育期和不同器官（根、茎、叶片、叶鞘）的固氮酶活性。结果显示，4个品种甘蔗及接菌后各器官的固氮酶活性均在伸长初期或伸长盛期达到高峰，且以根和茎较高，叶、叶鞘次之；‘B1’、‘B8’根的接菌效果最佳，其固氮酶活性分别比对照增加13．22％和12．42％，而‘B1’和‘ROC16’茎的固氮酶活性分别比对照提高12．19％和12．02％，叶片提高了8％～9％，叶鞘的固氮酶活性变化最小；4个品种甘蔗固氮酶活性表现为‘B8’〉‘B1’〉‘ROC22’〉‘ROC16’，且品种‘B8’与‘ROC22’和‘ROC16’存在显著或极显著差异；相对于品种‘ROC22’和‘ROC16’，固氮菌R16SH对‘B1’与‘B8’的株高以及‘B1’的茎径有更好的生长诱导效应，且在伸长期表现最明显。研究表明，甘蔗的固氮酶活性在品种、器官及生育期间均存在明显差异，接种固氮菌能不同程度提高各品种器官的固氮酶活性，且各品种根、茎以及‘B1’和‘B8’的叶片固氮酶活性显著或极显著差异增加；巴西固氮甘蔗品种表现出比广西主栽甘蔗品种更强的固氮酶活性，且对接种固氮菌反应更敏感。

英文摘要：

The nitrogenase activities at different growth periods of sugarcane by inoculating nitrogen fixing bacteria R16SH were investigated in two Brazilian nitrogen fixing sugarcane varieties（＇B1＇,＇B8＇）,and two local varieties（＇ROC22＇,＇ROC16＇）.It had shown that the nitrogenase activities in roots and stalks were higher than those in leaves and sheathes in four cultivars,and it reached the summit in the rapidly elongating period or at the beginning of the elongating period in all organs.The Brazilian nitrogen fixing varieties ＇B1＇and＇B8＇after inoculation showed a better nitrogen fixing ability in roots compared to the control,which enhanced 13.22% and 12.42% respectively.The nitrogenase activities in the stems of ＇B1＇ and ＇ROC16＇ improved 12.19% and 12.02% respectively,the nitrogenase activities in leaves increased 8%～9%,the change in sheathes was the lowest among these organs.The nitrogen fixing ability was ＇B8＇〉＇B1＇〉＇ROC22＇〉＇ROC16＇.＇B8＇ showed significant different compared to ＇ROC22＇ and ＇ROC16＇.It has inducing efficiency in height of ＇B1＇and＇B8＇and stem diameter of ＇B1＇ by inoculating nitrogen fixing bacteria R16SH.The obvious effect was observed at the elongation stage.Therefore,it was shown that the nitrogenase activities were significantly different in organs,varieties and growth stage,and it was promoted in a certain extent by inoculating nitrogen fixing bacteria.The nitrogenase activities in roots and stalks showed significant difference compared to the control in these varieties（at P〈0.05 or P〈0.01）,and the same results in the leaves in certain growth stage of ＇B1＇ and ＇B8＇ were also observed.The results indicated that the Brazilian cultivars had higher nitrogen fixation ability than Guangxi local cultivars.Brazilian cultivars were more sensitive to nitrogen fixing bacteria than Guangxi local cultivars.