不同花生品种根瘤固氮特点及其与产量的关系
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摘要
花生根系着生根瘤,能够直接利用大气中的氮气作为氮源,在花生氮素供应中占有举足轻重的地位.而有关根瘤高效固氮的机理研究甚少.本研究在盆栽条件下,利用~(15)N示踪技术,研究了19个花生品种根瘤固氮特点及其与产量的关系.结果表明:不同品种根瘤数量、鲜质量、内含物质和固氮量等指标品种间存在显著差异.根瘤数量和鲜质量变异幅度分别为每盆170.59～696.15个和0.83～3.74 g,变异系数分别为36.1%和41.1%;豆血红蛋白含量和固氮酶活性变异幅度分别为每盆15.51～23.23 mg和2.75～20.46μmol C_2H_4·h~(-1),变异系数分别为13.1%和57.2%,后者明显高于前者,表明固氮酶活性除受豆血红蛋白含量影响外,同时受到其他因素的影响.根瘤固氮和全氮积累量变异幅度分别为每盆0.71～1.82和2.16～3.72 g,变异系数分别为21.6%和12.9%,前者明显高于后者,表明花生根瘤固氮不足时,其他氮源在一定程度上能自动补偿根瘤留下的匮缺.花生以根瘤固氮为主,供氮比例平均占总氮量的2/5以上,最高可达50%,培育高供氮比例的品种,可作为花生减氮栽培的途径之一.上述指标中,除根瘤数量外,其余指标间以及这些指标与产量均呈极显著正相关,表明根瘤固氮生理指标与根瘤供氮能力及最终产量密切相关,提高这些指标有助于同时实现高产和化肥减施.
Root nodules in peanut(Arachis hypogaea L.) could directly utilize nitrogen(N) in the atmosphere as N source, which plays an important role in the N supply in peanut. However, little is known about the mechanism of efficient N fixation by root nodule. In this study, ~(15)N tracer technology was used to investigate the characteristics of N fixation by root nodule and its relationship with peanut yields of 19 varieties in a pot culture experiment. Results showed that there were significant differences in nodule number, fresh quality, internal material, N fixation amount and other related indices among different varieties. The range of number and fresh mass of root nodule was 170.59-696.15 per pot and 0.83-3.74 g per pot, with coefficients of variation(CV) of 36.1% and 41.1%, respectively. The range of leghaemoglobin content and nitrogenase activity was 15.51-23.23 mg per pot and 2.75-20.46 μmol C_2H_4·h~(-1) per pot, with CV of 13.1% and 57.2%, respectively. The CV of nitrogenase activity was significantly higher than that of leghaemoglobin content, indicating that nitrogenase activity was not only affected by leghaemoglobin content but also other factors. The range of N fixation by root nodule and total N accumulation was 0.71-1.82 and 2.16-3.72 g per pot, with CV of 21.6% and 12.9%, respectively. The CV of the former was significantly higher than that of the latter, indicating that other N sources could automatically compensate the deficit when N fixation of root nodule was insufficient. Nitrogen fixation by root nodule was one of the main N sources for peanut, while the average N supply percentage was more than 40% of the total N, with a maximum of 50%. Cultivating the variety with high N supply capacity is an effective way for N-saving cultivation in the peanut production. Except for nodule number, there were significantly positive correlations between the other indices and peanut yield, indicating that the physiological indicators of N fixation were closely related to N fixation capacity by root nodule and the final yield. Therefore, enhancing these characters would help achieve high yield of peanut and simultaneously reduce fertilizer application.
Root nodules in peanut(Arachis hypogaea L.) could directly utilize nitrogen(N) in the atmosphere as N source, which plays an important role in the N supply in peanut. However, little is known about the mechanism of efficient N fixation by root nodule. In this study, ~(15)N tracer technology was used to investigate the characteristics of N fixation by root nodule and its relationship with peanut yields of 19 varieties in a pot culture experiment. Results showed that there were significant differences in nodule number, fresh quality, internal material, N fixation amount and other related indices among different varieties. The range of number and fresh mass of root nodule was 170.59-696.15 per pot and 0.83-3.74 g per pot, with coefficients of variation(CV) of 36.1% and 41.1%, respectively. The range of leghaemoglobin content and nitrogenase activity was 15.51-23.23 mg per pot and 2.75-20.46 μmol C_2H_4·h~(-1) per pot, with CV of 13.1% and 57.2%, respectively. The CV of nitrogenase activity was significantly higher than that of leghaemoglobin content, indicating that nitrogenase activity was not only affected by leghaemoglobin content but also other factors. The range of N fixation by root nodule and total N accumulation was 0.71-1.82 and 2.16-3.72 g per pot, with CV of 21.6% and 12.9%, respectively. The CV of the former was significantly higher than that of the latter, indicating that other N sources could automatically compensate the deficit when N fixation of root nodule was insufficient. Nitrogen fixation by root nodule was one of the main N sources for peanut, while the average N supply percentage was more than 40% of the total N, with a maximum of 50%. Cultivating the variety with high N supply capacity is an effective way for N-saving cultivation in the peanut production. Except for nodule number, there were significantly positive correlations between the other indices and peanut yield, indicating that the physiological indicators of N fixation were closely related to N fixation capacity by root nodule and the final yield. Therefore, enhancing these characters would help achieve high yield of peanut and simultaneously reduce fertilizer application.
引文
[1] Zhou L-Y (周录英), Li X-D (李向东), Tang X (汤笑), et al. Effects of different application amount of N, P, K fertilizers on physiological characteristics, yield and kernel quality of peanut. Chinese Journal of Applied Ecology (应用生态学报), 2007, 18(11): 2468-2474 (in Chinese)
[2] Zhang Z-M (张智猛), Wan S-B (万书波), Ning T-Y (宁堂原), et al. Effects of nitrogen level on nitrogen metabolism and correlating enzyme activity in peanut. Chinese Journal of Plant Ecology (植物生态学报), 2008, 32(6): 1407-1416 (in Chinese)
[3] Yang J-S (杨吉顺), Li S-X (李尚霞), Zhang Z-M (张智猛), et al. Effect of nitrogen application on canopy photosynthetic and dry matter accumulation of peanut. Journal of Nuclear Agricultural Sciences (核农学报), 2014, 28(1): 154-160 (in Chinese)
[4] Wang C-B (王才斌), Wu Z-F (吴正锋), Sun X-W (孙学武), et al. Physiological and Ecological and High Efficiency Fertilization of Peanut Nutrition. Beijing: China Agriculture Press, 2017 (in Chinese)
[5] Zheng Y-M (郑永美), Wang C-X (王春晓), Liu Q-M (刘岐茂), et al. Effect of nitrogen fertilizer regulation on root growth and nodulating ability of peanut. Journal of Nuclear Agricultural Sciences (核农学报), 2017, 31(12): 2418-2425 (in Chinese)
[6] Wu Z-F (吴正锋), Chen D-X (陈殿绪), Zheng Y-M (郑永美), et al. Supply characteristics of different nitrogen sources and nitrogen use efficiency of peanut. Chinese Journal of Oil Crop Sciences (中国油料作物学报), 2016, 38(2): 207-213 (in Chinese)
[7] Wang CB, Zheng YM, Shen P, et al. Determining N supplied sources and N use efficiency for peanut under applications of four forms of N fertilizers labeled by isotope 15N. Journal of Integrative Agriculture, 2016, 15: 432-439
[8] Zuo Y-M (左元梅), Liu Y-X (刘永秀), Zhang F-S (张福锁). Effects of the NO3--N on nodule formation and nitrogen fixing of peanut. Acta Ecologica Sinica (生态学报), 2003, 23(4): 758-764 (in Chinese)
[9] Sun H (孙虎), Li S-X (李尚霞), Wang Y-F (王月福), et al. Effects of nitrogen application on source of nitrogen accumulation and yields of different peanut cultivars. Plant Nutrition and Fertilizer Science (植物营养与肥料学报), 2010, 16(1): 153-157 (in Chinese)
[10] Zhang X (张翔), Zhang X-Y (张新友), Zhang Y-T (张玉亭), et al. Effects of nitrogen application rate on nodulation, nitrogen absorption and utilization of peanut. Journal of Peanut Science (花生学报), 2012, 41(4): 12-17 (in Chinese)
[11] Li H-X (李海先), Li X-M (李新民), Danso SKA. Use of 15N dilution method for screening soybean lines with high yield and high nitrogen fixation ability. Acta Agriculturae Nucleatae Sinica (核农学报), 1998, 12(5): 299-303 (in Chinese)
[12] Zheng Y-M (郑永美), Sun X-S (孙秀山), Wang C-B (王才斌), et al. Differences in nitrogen utilization characteristics of different peanut genotypes in high fertility soils. Chinese Journal of Applied Ecology (应用生态学报), 2016, 27(12): 3977-3986 (in Chinese)
[13] Song H-Y (宋鸿遇). Technical Manuals of Botanical Physiology Experiment. Shanghai: Science and Techno-logy Press, 1985 (in Chinese)
[14] Li H (李慧), Ding W (丁伟), Jiang J-F (姜俊凤), et al. Research on the inhibitory mechanism of imazethapyr to nodule nitrogenase activity in soybean. Scientia Agricultura Sinica (中国农业科学), 2013, 46(19): 4173-4178 (in Chinese)
[15] Zhang Z-L (张志良), Qu W-J (瞿伟菁). The Experimental Guide for Plant Physiology. Beijing: Higher Education Press, 2003 (in Chinese)
[16] Ding W, Reddy KN, Zablotowicz RM, et al. Physiological responses of glyphosate-resistant and glyphosate sensitive soybean to aminomethyl phosphonic acid, a meta-bolite of glyphosate. Chemosphere, 2011, 83: 593-598
[17] Zhong Z-T (钟增涛), Shen Q-R (沈其荣), Sun X-H (孙晓红), et al. Role of Rhizobium in wheat-astragalus mixed cropping system. Chinese Journal of Applied Eco-logy (应用生态学报), 2003, 14(2): 187-190 (in Chinese)
[18] Chou M-X (丑敏霞), Wei X-Y (魏新元). Review of research advancements on the molecular basis and regulation of symbiotic nodulation of legumes. Chinese Journal of Plant Ecology (植物生态学报), 2010, 34(7): 876-888 (in Chinese)
[19] Liu Y, Wu L, Baddeley JA, et al. Models of biological nitrogen fixation of legumes: A review. Agronomy for Sustainable Development, 2011, 31: 155-172
[20] Sato T, Onoma N, Fujikake H. Changes in four leghemoglobin components in nodules of hypernodulating soybean (Glycine max Merr.) mutant and its parent in the early nodule developmental stage. Plant and Soil, 2001, 237: 129-135
[21] Daimon H, Yoshioka M. Responses of root nodule formation and nitrogen fixation activity to nitrate in a split-root system in peanut (Arachis hypogaea L.). Journal of Agronomy and Crop Science, 2008, 187: 89-95
[22] Liu X-J (刘晓静), Ye F (叶芳), Zhang X-L (张晓玲). Effects of exogenous nitrogen forms on root chara-cteristics of alfalfa at different growth stages. Acta Prata-culturae Sinica (草业学报), 2015, 24(6): 53-63 (in Chinese)
[23] Xia X (夏玄), Gong Z-P (龚振平). Research advance on the relationship between nitrogen and leguminous nitrogen fixation. Journal of Northeast Agricultural University (东北农业大学学报), 2017, 48(1): 79-88 (in Chinese)
[24] Lea PJ, Miflin BJ. Glutamate synthase and the synthesis of glutamate in plants. Plant Physiology and Biochemistry, 2003, 41: 555-564
[25] He Q-Y (何庆元), Yu Y-X (玉永雄), Hu Y (胡艳). Study on variation of nodulation and nitrogen fixing capacity of different Rhizobium meliloti. Chinese Journal of Grassland (中国草地学报), 2006(4): 79-83 (in Chinese)
[26] Feng B-Z (冯博政), Liu X-J (刘晓静), Hao F (郝凤), et al. Correlation and effects of exogenous nitrogen on nitrogenase activity and ureide content of Medicago sativa L. Acta Agrestia Sinica (草地学报), 2016, 24(2): 351-357 (in Chinese)
[27] Liu W (刘伟), Yang L-F (杨立飞), Zhu W-L (朱文莉), et al. Effects of OsPT6 gene overexpression on nodulation and nitrogen fixation of vegetable soybean under low phosphorus conditions. Acta Botanica Boreali-Occidentalia Sinica (西北植物学报), 2016, 36(2): 266-273 (in Chinese)
[28] Wang M-L (王梦亮), Zhang R (张蕊), Wang J-H (王俊宏), et al. Soybean growth and nitrogen fixation affected by different concentration of nodule growth-promoting agent. Soybean Science (大豆科学), 2011, 30(2): 246-249 (in Chinese)
[29] Wang C-B (王才斌), Cheng B (成波), Sun X-S (孙秀山), et al. Effect of distribution modes of nitrogenous fertilizer on wheat and peanut yields and the nitroge-nous fertilizer utilization ratio under the wheat-peanut cropping system. Acta Agriculturae Nucleatae Sinica (核农学报), 2002, 16(2): 98-102 (in Chinese)
[30] Zheng Y-M (郑永美), Wang C-B (王才斌), Wan G-B (万更波), et al. Effects of nitrogen forms on nitrogen metabolism and accumulation in peanut. Shandong Agricultural Sciences (山东农业科学), 2012, 44(2): 57-62 (in Chinese)
[31] Alam F, Bhuiyan MAH, Alam SS, et al. Effect of Rhizobium sp. BARIRGm901 inoculation on nodulation, nitrogen fixation and yield of soybean (Glycine max) genotypes in gray terrace soil. Bioscience, Biotechnology, and Biochemistry, 2015, 79: 1684-1694
[32] Wan S-B (万书波), Feng H-S (封海胜), Zuo X-Q (左学青), et al. Nitrogen use efficiency of different nitrogen supply level of peanut. Shandong Agricultural Sciences (山东农业科学), 2000(1): 31-33 (in Chinese)
[33] Zhu C-P (朱长甫), Miao Y-N (苗以农), Yang W-J (杨文杰), et al. Correlation between soybean seed protein content and nitrogenase activity and nitrate reductase activity. Chinese Journal of Oil Crop Sciences (中国油料作物学报), 1992, 14(2): 45-47 (in Chinese)
[34] Ferguson BJ, Indrasumunar A, Hayashi S, et al. Mole-cular analysis of legume nodule development and autore-gulation. Journal of Integrative Plant Biology, 2010, 52: 61-76
[35] Liu W-Y (刘文钰), Yong T-W (雍太文), Liu X-M (刘小明), et al. Effect of reduced N application on nodule N fixation, N uptake and utilization of soybean in maize-soybean relay strip intercropping system. Soybean Science (大豆科学), 2014, 33(5): 705-712 (in Chinese)
[36] Ye F (叶芳), Liu X-J (刘晓静), Zhang J-X (张进霞). Effects of nitrogen forms on the nitrogen metabolism of alfalfa ‘Gannong No. 3’ varity at different growth stages. Acta Agrestia Sinica (草地学报), 2015, 23(2): 285-293 (in Chinese)
[37] Jiang Y (姜妍), Wang Q-Q (王清泉), Li Y-M (李远明), et al. Effect of different nitrogen application levels on the root morphology, nodulation and nitrogen fixation in 7S subunit lacked soybean. Soybean Science (大豆科学), 2017, 36(2): 267-273 (in Chinese)
[38] Yang W-Y (杨文英), Du Q (杜青), Yang H (杨航), et al. Effect of different varieties and root barriers on soybean nodule nitrogen fixation and nitrogen uptake in maize/soybean intercropping system. Journal of Sichuan Agricultural University (四川农业大学学报), 2016, 34(1): 1-5 (in Chinese)
[2] Zhang Z-M (张智猛), Wan S-B (万书波), Ning T-Y (宁堂原), et al. Effects of nitrogen level on nitrogen metabolism and correlating enzyme activity in peanut. Chinese Journal of Plant Ecology (植物生态学报), 2008, 32(6): 1407-1416 (in Chinese)
[3] Yang J-S (杨吉顺), Li S-X (李尚霞), Zhang Z-M (张智猛), et al. Effect of nitrogen application on canopy photosynthetic and dry matter accumulation of peanut. Journal of Nuclear Agricultural Sciences (核农学报), 2014, 28(1): 154-160 (in Chinese)
[4] Wang C-B (王才斌), Wu Z-F (吴正锋), Sun X-W (孙学武), et al. Physiological and Ecological and High Efficiency Fertilization of Peanut Nutrition. Beijing: China Agriculture Press, 2017 (in Chinese)
[5] Zheng Y-M (郑永美), Wang C-X (王春晓), Liu Q-M (刘岐茂), et al. Effect of nitrogen fertilizer regulation on root growth and nodulating ability of peanut. Journal of Nuclear Agricultural Sciences (核农学报), 2017, 31(12): 2418-2425 (in Chinese)
[6] Wu Z-F (吴正锋), Chen D-X (陈殿绪), Zheng Y-M (郑永美), et al. Supply characteristics of different nitrogen sources and nitrogen use efficiency of peanut. Chinese Journal of Oil Crop Sciences (中国油料作物学报), 2016, 38(2): 207-213 (in Chinese)
[7] Wang CB, Zheng YM, Shen P, et al. Determining N supplied sources and N use efficiency for peanut under applications of four forms of N fertilizers labeled by isotope 15N. Journal of Integrative Agriculture, 2016, 15: 432-439
[8] Zuo Y-M (左元梅), Liu Y-X (刘永秀), Zhang F-S (张福锁). Effects of the NO3--N on nodule formation and nitrogen fixing of peanut. Acta Ecologica Sinica (生态学报), 2003, 23(4): 758-764 (in Chinese)
[9] Sun H (孙虎), Li S-X (李尚霞), Wang Y-F (王月福), et al. Effects of nitrogen application on source of nitrogen accumulation and yields of different peanut cultivars. Plant Nutrition and Fertilizer Science (植物营养与肥料学报), 2010, 16(1): 153-157 (in Chinese)
[10] Zhang X (张翔), Zhang X-Y (张新友), Zhang Y-T (张玉亭), et al. Effects of nitrogen application rate on nodulation, nitrogen absorption and utilization of peanut. Journal of Peanut Science (花生学报), 2012, 41(4): 12-17 (in Chinese)
[11] Li H-X (李海先), Li X-M (李新民), Danso SKA. Use of 15N dilution method for screening soybean lines with high yield and high nitrogen fixation ability. Acta Agriculturae Nucleatae Sinica (核农学报), 1998, 12(5): 299-303 (in Chinese)
[12] Zheng Y-M (郑永美), Sun X-S (孙秀山), Wang C-B (王才斌), et al. Differences in nitrogen utilization characteristics of different peanut genotypes in high fertility soils. Chinese Journal of Applied Ecology (应用生态学报), 2016, 27(12): 3977-3986 (in Chinese)
[13] Song H-Y (宋鸿遇). Technical Manuals of Botanical Physiology Experiment. Shanghai: Science and Techno-logy Press, 1985 (in Chinese)
[14] Li H (李慧), Ding W (丁伟), Jiang J-F (姜俊凤), et al. Research on the inhibitory mechanism of imazethapyr to nodule nitrogenase activity in soybean. Scientia Agricultura Sinica (中国农业科学), 2013, 46(19): 4173-4178 (in Chinese)
[15] Zhang Z-L (张志良), Qu W-J (瞿伟菁). The Experimental Guide for Plant Physiology. Beijing: Higher Education Press, 2003 (in Chinese)
[16] Ding W, Reddy KN, Zablotowicz RM, et al. Physiological responses of glyphosate-resistant and glyphosate sensitive soybean to aminomethyl phosphonic acid, a meta-bolite of glyphosate. Chemosphere, 2011, 83: 593-598
[17] Zhong Z-T (钟增涛), Shen Q-R (沈其荣), Sun X-H (孙晓红), et al. Role of Rhizobium in wheat-astragalus mixed cropping system. Chinese Journal of Applied Eco-logy (应用生态学报), 2003, 14(2): 187-190 (in Chinese)
[18] Chou M-X (丑敏霞), Wei X-Y (魏新元). Review of research advancements on the molecular basis and regulation of symbiotic nodulation of legumes. Chinese Journal of Plant Ecology (植物生态学报), 2010, 34(7): 876-888 (in Chinese)
[19] Liu Y, Wu L, Baddeley JA, et al. Models of biological nitrogen fixation of legumes: A review. Agronomy for Sustainable Development, 2011, 31: 155-172
[20] Sato T, Onoma N, Fujikake H. Changes in four leghemoglobin components in nodules of hypernodulating soybean (Glycine max Merr.) mutant and its parent in the early nodule developmental stage. Plant and Soil, 2001, 237: 129-135
[21] Daimon H, Yoshioka M. Responses of root nodule formation and nitrogen fixation activity to nitrate in a split-root system in peanut (Arachis hypogaea L.). Journal of Agronomy and Crop Science, 2008, 187: 89-95
[22] Liu X-J (刘晓静), Ye F (叶芳), Zhang X-L (张晓玲). Effects of exogenous nitrogen forms on root chara-cteristics of alfalfa at different growth stages. Acta Prata-culturae Sinica (草业学报), 2015, 24(6): 53-63 (in Chinese)
[23] Xia X (夏玄), Gong Z-P (龚振平). Research advance on the relationship between nitrogen and leguminous nitrogen fixation. Journal of Northeast Agricultural University (东北农业大学学报), 2017, 48(1): 79-88 (in Chinese)
[24] Lea PJ, Miflin BJ. Glutamate synthase and the synthesis of glutamate in plants. Plant Physiology and Biochemistry, 2003, 41: 555-564
[25] He Q-Y (何庆元), Yu Y-X (玉永雄), Hu Y (胡艳). Study on variation of nodulation and nitrogen fixing capacity of different Rhizobium meliloti. Chinese Journal of Grassland (中国草地学报), 2006(4): 79-83 (in Chinese)
[26] Feng B-Z (冯博政), Liu X-J (刘晓静), Hao F (郝凤), et al. Correlation and effects of exogenous nitrogen on nitrogenase activity and ureide content of Medicago sativa L. Acta Agrestia Sinica (草地学报), 2016, 24(2): 351-357 (in Chinese)
[27] Liu W (刘伟), Yang L-F (杨立飞), Zhu W-L (朱文莉), et al. Effects of OsPT6 gene overexpression on nodulation and nitrogen fixation of vegetable soybean under low phosphorus conditions. Acta Botanica Boreali-Occidentalia Sinica (西北植物学报), 2016, 36(2): 266-273 (in Chinese)
[28] Wang M-L (王梦亮), Zhang R (张蕊), Wang J-H (王俊宏), et al. Soybean growth and nitrogen fixation affected by different concentration of nodule growth-promoting agent. Soybean Science (大豆科学), 2011, 30(2): 246-249 (in Chinese)
[29] Wang C-B (王才斌), Cheng B (成波), Sun X-S (孙秀山), et al. Effect of distribution modes of nitrogenous fertilizer on wheat and peanut yields and the nitroge-nous fertilizer utilization ratio under the wheat-peanut cropping system. Acta Agriculturae Nucleatae Sinica (核农学报), 2002, 16(2): 98-102 (in Chinese)
[30] Zheng Y-M (郑永美), Wang C-B (王才斌), Wan G-B (万更波), et al. Effects of nitrogen forms on nitrogen metabolism and accumulation in peanut. Shandong Agricultural Sciences (山东农业科学), 2012, 44(2): 57-62 (in Chinese)
[31] Alam F, Bhuiyan MAH, Alam SS, et al. Effect of Rhizobium sp. BARIRGm901 inoculation on nodulation, nitrogen fixation and yield of soybean (Glycine max) genotypes in gray terrace soil. Bioscience, Biotechnology, and Biochemistry, 2015, 79: 1684-1694
[32] Wan S-B (万书波), Feng H-S (封海胜), Zuo X-Q (左学青), et al. Nitrogen use efficiency of different nitrogen supply level of peanut. Shandong Agricultural Sciences (山东农业科学), 2000(1): 31-33 (in Chinese)
[33] Zhu C-P (朱长甫), Miao Y-N (苗以农), Yang W-J (杨文杰), et al. Correlation between soybean seed protein content and nitrogenase activity and nitrate reductase activity. Chinese Journal of Oil Crop Sciences (中国油料作物学报), 1992, 14(2): 45-47 (in Chinese)
[34] Ferguson BJ, Indrasumunar A, Hayashi S, et al. Mole-cular analysis of legume nodule development and autore-gulation. Journal of Integrative Plant Biology, 2010, 52: 61-76
[35] Liu W-Y (刘文钰), Yong T-W (雍太文), Liu X-M (刘小明), et al. Effect of reduced N application on nodule N fixation, N uptake and utilization of soybean in maize-soybean relay strip intercropping system. Soybean Science (大豆科学), 2014, 33(5): 705-712 (in Chinese)
[36] Ye F (叶芳), Liu X-J (刘晓静), Zhang J-X (张进霞). Effects of nitrogen forms on the nitrogen metabolism of alfalfa ‘Gannong No. 3’ varity at different growth stages. Acta Agrestia Sinica (草地学报), 2015, 23(2): 285-293 (in Chinese)
[37] Jiang Y (姜妍), Wang Q-Q (王清泉), Li Y-M (李远明), et al. Effect of different nitrogen application levels on the root morphology, nodulation and nitrogen fixation in 7S subunit lacked soybean. Soybean Science (大豆科学), 2017, 36(2): 267-273 (in Chinese)
[38] Yang W-Y (杨文英), Du Q (杜青), Yang H (杨航), et al. Effect of different varieties and root barriers on soybean nodule nitrogen fixation and nitrogen uptake in maize/soybean intercropping system. Journal of Sichuan Agricultural University (四川农业大学学报), 2016, 34(1): 1-5 (in Chinese)