Nodule Formation and Development in Soybeans (Glycine max L.) in Response to Phosphorus Supply in Solution Culture

• Published in: Pedosphere Vol. 17; no. 1; pp. 36 - 43
• Main Authors: MIAO, Shu-Jie, QIAO, Yun-Fa, HAN, Xiao-Zeng, AN, M.
• Format: Journal Article
• Language: English
• Published: Key Laboratory of Soybean Biology of Ministry of Education, Harbin 150030 (China) 01.02.2007; Graduate School of the Chinese Academy of Sciences,Beijing 100049(China)%Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin 150081 (China)%E. H. Graham Centre for Agricultural Innovation, NSW Department of Primary Industries & Charles Sturt University,Wagga Wagga, NSW 2650 (Australia); Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin 150081 (China)
• Subjects: nodulation; inoculation level; nitrogen fixation; phosphorus; soybeans
• ISSN: 1002-0160; 2210-5107
• DOI: 10.1016/S1002-0160(07)60005-8

S1; Phosphorus (P) is necessary for growth and nitrogen fixation, and thus its deficiency is a major factor limiting legume production in most agricultural soils. The effect of phosphorus supply on nodule development and its role in soybeans (Glycine max L.) was studied in a nutrient solution. Plants were inoculated with Bradyrhizobium japonicum and grown for 35 days in a glasshouse at a day and night temperature of 25 ℃ and 15 ℃, respectively. Although increasing P supply increased the concentrations of P and N in the shoots and roots, the external P supply did not significantly affect the P concentration in the nodules, and the N fixed per unit nodule biomass decreased with increasing P supply. The nitrogen content in the shoots correlated well with the P content (r = 0.92**). At an inoculation level of 102 cells mL-1, the P supply did not affect the number of nodules; however, at inoculation levels of 103.5 and 105 cells mL-1, increasing P supply increased both the number and size of nodules. Irrespective of the inoculation level, increasing P supply increased the nodule biomass relative to the biomass of the host plant. It is suggested that the P deficiency specifically inhibited the nodule development and thereby the total N2 fixation.