Nodulation Capacity of Argentinean Soybean (<i>Glycine max</i>L. Merr) Cultivars Inoculated with Commercial Strains of <i>Bradyrhizobium japonicum</i>

The purpose of this research was to evaluate the nodulation potential of 31 Argentinean soybean commercial cultivars. Those with the highest nodulation capacity response developed twice the amount of nodules than the low nodulating ones, which is the variation contained in soybean genotypes. Furthermore, this was not due to bacterial promiscuity, since the response was independent of the bradyrhizobia strain inoculated. The ability of cultivars to develop a larger number and biomass of nodules was unrelated with the maturity group they belong to and also was not a response to quorum sensing effects. Our results suggest that breeding programs can be aimed at improving the nodulation capacity of soybean and that cultivars from different maturity groups can be a source of nodulation QTLs.

铵硝配比对大豆生长及结瘤固氮的影响

通过水培方法在5种不同铵硝配比下,研究不同氮形态及接种根瘤菌对大豆生长、结瘤固氮的影响及其生理机制。结果表明,不同铵硝配比对大豆植株生长、产量、生物固氮及氮效率等影响显著,随硝氮比例增加,植株生物量、籽粒产量、结瘤固氮及氮效率等指标均呈现先增加后降低的趋势,以铵硝比25∶75处理效果最佳,总体表现为铵硝比25∶75≥0∶100>50∶50>75∶25>100∶0。较高铵硝比(≥50∶50)严重抑制了大豆根系的伸长生长、根瘤的形成及其固氮酶的活性,从而降低了生物固氮的贡献率,最终导致大豆产量及氮素效率的降低。接种根瘤菌显著增加大豆产量和籽粒含氮量,并与铵硝比之间存在协同效应。铵硝比为25∶75时接种根瘤菌,氮效率最高,最有利于大豆生长及籽粒产量的形成。研究结果对优化大豆水培营养液配方以及指导农田生产中氮素合理施用均有较强的借鉴作用。