利用^(15)N_(2)直接标记法研究水稻种植对稻田固氮量和固氮活性的影响  

Effects of Rice Planting on Nitrogen Fixation Amount and Activity in Paddy Field Using ^(15)N_(2) Direct Labeling Method

作　　者：张燕辉 胡天龙 王慧 靳海洋 刘本娟 刘红涛 刘琦 林志斌[1,2] 蔺兴武 谢祖彬[1] ZHANG Yanhui;HU Tianlong;WANG Hui;JIN Haiyang;LIU Benjuan;LIU Hongtao;LIU Qi;LIN Zhibin;LIN Xingwu;XIE Zubin(State Key Laboratory of Soil and Sustainable Agriculture,Institute of Soil Science,Chinese Academy of Sciences,Nanjing 210008,China;University of Chinese Academy of Sciences,Beijing 100049,China;College of Forestry,Nanjing Forestry University,Nanjing 210008,China)

机构地区：[1]土壤与农业可持续发展国家重点实验室(中国科学院南京土壤研究所),南京210008 [2]中国科学院大学,北京100049 [3]南京林业大学林学院,南京210008

出　　处：《土壤》2021年第4期739-745,共7页Soils

基　　金：国家科技基础性工作专项(2015FY110700);国家自然科学基金项目(31870500,41501273)资助。

摘　　要：稻田固氮对土壤维持肥力有着重要的作用,但水稻种植与固氮菌及其活性之间的关系尚不清楚。本试验利用15N2直接标记法测定了下位砂姜土发育的简育水耕人为土在种水稻和不种水稻条件下的生物固氮量,及其在土壤不同层次(0~1、1~5、5~15 cm)和水稻中的分配,并通过实时荧光定量PCR技术测定了土壤中固氮菌nifH DNA及RNA基因数量。结果表明:种水稻处理显著提高了土壤各层固氮量,尤其提高了1~5 cm和5~15 cm土层土壤固氮量对总固氮量的贡献;种水稻处理的总固氮量是不种水稻处理的10.3倍;水稻植株中生物固定的氮占总固氮量的31.48%;在0~1 cm土层,种水稻处理显著提高了nifH RNA基因数量,而对nifH DNA基因数量的增加不显著。可见,水稻种植没有增加固氮菌的数量,稻田固氮量的增加是因为水稻种植极大地促进了固氮菌nifH基因的表达,提高了固氮菌的固氮活性。Paddy N_(2) fixation plays an important role for soil fertility maintenance,however,the relationship between rice planting and activity of diazotrophs to fix N_(2) remains elusive.In this paper the amount of biological nitrogen fixation(BNF)and its distribution in different soil layers(0–1,1–5,5–15 cm)and rice were measured by ^(15)N_(2) direct labeling method.The abundances of nitrogen fixing bacteria and active nitrogen fixing bacteria in soil were determined by real-time quantitative PCR(qPCR).The results showed that rice planting significantly increased nitrogen fixation amount in each soil layer,and also increased the contribution of 1–5 cm and 5–15 cm layers to total nitrogen fixation.Total nitrogen fixation amount in rice planting treatment was 10.3 times higher than CK.The fixed N_(2) allocated to rice plants accounted for 31.48%of the total nitrogen fixation.In 0–1cm soil layer,rice planting significantly increased the number of nifH RNA gene,but did not significantly increase the number of nifH DNA gene.These results indicated that rice planting did not increase the number of nitrogen fixing bacteria.The increase of nitrogen fixation amount in rice field is because rice planting greatly promoted the expression of nifH gene of nitrogen fixing bacteria,thus improved nitrogen fixation activity of nitrogen fixing bacteria.

关 键 词：生物固氮 固氮活性 稻田 ^(15)N_(2)直接标记法 nifH反转录 

分 类 号：S51[农业科学—作物学] S-3