Variations in the responses of Acacia mangium to inoculation with different strains of Bradyrhizobium sp. under nursery conditions
Jayakumar, P. Tan, T.K.
Jayakumar, P.
Citations
Altmetric:
Alternative Title
Abstract
Acacia mangium Willd. is a leguminous tree that can form symbiotic association with N2-fixing Bradyrhizobium sp. A nursery experiment was conducted to study the variations in the responses of A. mangium seedlings to inoculation with different strains of Bradyrhizobium in terms of dry matter production and allocation to underground parts, P uptake, and nodulation and N2 fixation. Bradyrhizobium strains Aust 11c, Aust 13c, BuT 2, Nlu 27, Tel 2 and Was 9 were used in the present study. Inoculated seedlings were also compared with N-fed seedlings. All the inoculated seedlings allocated more biomass for undergrowth and had higher P contents when compared to N-fed seedlings. However, N-fed seedlings had higher N contents. The shoot N:P ratio was significantly higher in N-fed seedling when compared to Bradyrhizobium- inoculated seedlings indicating imbalances in nutrient uptake. Among the different strains of Bradyrhizobium, Was-9-inoculated seedlings allocated more biomass for root and nodule growth, and had higher N and P contents when compared to seedlings inoculated with other strains. Only inoculation with Was 9 had a significant positive effect on the growth of A. mangium when compared to N application. The differences in underground production in A. mangium seedlings inoculated with different strains of Bradyrhizobium can be attributed to the differences in nodule carbon consumption. Strains that efficiently utilize the resources allocated for N2 fixation can stimulate underground growth without affecting aboveground production, and such strains are more suitable for inoculation to nursery seedlings used in reforestation programme. ©2006 Balaban.
Keywords
Acacia mangium, Bradyrhizobium, N2 fixation, Nodulation, P uptake
Source Title
Symbiosis
Publisher
Series/Report No.
Collections
Rights
Date
2006
DOI
Type
Article