Paddy System with a Hybrid Rice Enhances Cyanobacteria Nostoc and Increases N2 Fixation  

作　　者：MA Jing BEI Qicheng WANG Xiaojie LIU Gang Georg CADISCH LIN Xingwu ZHU Jianguo SUN Xiaoli XIE Zubin 

机构地区：[1]State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China) [2]University of Chinese Academy of Sciences, Beijing 100049 (China) [3]Institute of Agricultural Sciences in the TYopics (Hans-Ruthenberg-Institute), University of Hohenheim, Stuttgart 70593 (Germany)

出　　处：《Pedosphere》2019年第3期374-387,共14页土壤圈（英文版）

基　　金：the National Natural Science Foundation of China (Nos. 31870500, 40871146, and 41501273);the Special Project on the Basis of National Science and Technology of China (No. 2015FY110700);the Knowledge Innovation Program of Chinese Academy of Sciences (No. KZCX2-EW-409);the Technology Supporting Project of Jiangsu Province (No. BE2013451)

摘　　要：Biological nitrogen (N) fixation (BNF) plays a significant role in maintaining soil fertility in paddy field ecosystems. Rice variety influences BNF, but how different rice varieties regulate BNF and associated diazotroph communities has not been quantified. Airtight, field-based 15N2-labelling grow th chamber experiments were used to assess the BNF capac 辻 y of different rice varie ties. In addition, both the 16S rRNA and nifH genes were sequenced to assess the influence of different rice varieties on bacterial and diazotrophic communities in paddy soils. After subjecting a rice-soil system to 74 d of continuous airtight, field-based 15N2 labelling in pots in a growth chamber, the amounts of fixed N were 22.3 and 38.9 kg ha^-1 in inbred japonica (W23) and hybrid indica (IIY) rice cultivars plan ted in the rice-soil systems, respectively, and only 1%—2.5% of the fixed N was allocated to the rice plants and weeds. A greater abundance of diazotrophs was found in the surface soil (0-1 cm) under IIY than under W23. Sequencing of the 16S rRNA gene showed significantly greater abundances of the cyanobacterial genera Nostoc, Anabaena, and Cylindrospermum under IIY than under W23. Sequencing of the nifH gene also showed a significantly greater abundance of Nostoc under IIY than under W23. These results indicate that the hybrid rice cultivar (IIY) promoted BNF to a greater extent than the inbred rice cultivar (W23) and that the increase in BNF might have been due to the enhanced heterocystous cyanobacteria Nostoc.Biological nitrogen（N） fixation（BNF） plays a significant role in maintaining soil fertility in paddy field ecosystems. Rice variety influences BNF, but how different rice varieties regulate BNF and associated diazotroph communities has not been quantified. Airtight,field-based 15N2-labelling growth chamber experiments were used to assess the BNF capacity of different rice varieties. In addition,both the 16 S rRNA and nifH genes were sequenced to assess the influence of different rice varieties on bacterial and diazotrophic communities in paddy soils. After subjecting a rice-soil system to 74 d of continuous airtight, field-based 15N2 labelling in pots in a growth chamber, the amounts of fixed N were 22.3 and 38.9 kg ha-1 in inbred japonica（W23） and hybrid indica（IIY） rice cultivars planted in the rice-soil systems, respectively, and only 1%–2.5% of the fixed N was allocated to the rice plants and weeds. A greater abundance of diazotrophs was found in the surface soil（0–1 cm） under IIY than under W23. Sequencing of the 16 S rRNA gene showed significantly greater abundances of the cyanobacterial genera Nostoc, Anabaena, and Cylindrospermum under IIY than under W23.Sequencing of the nifH gene also showed a significantly greater abundance of Nostoc under IIY than under W23. These results indicate that the hybrid rice cultivar（IIY） promoted BNF to a greater extent than the inbred rice cultivar（W23） and that the increase in BNF might have been due to the enhanced heterocystous cyanobacteria Nostoc.

关 键 词：biological nitrogen FIXATION NIFH GENE 15N2 labelling rice variety 16S rRNA GENE 

分 类 号：P[天文地球]