Key Laboratory of Soil and Plant Nutrition in South China, Ministry of Agriculture; Root Biology Center, South China Agricultural University, Guangzhou 510642, China.
Mycorrhiza. 2011 Apr;21(3):173-81. doi: 10.1007/s00572-010-0319-1. Epub 2010 Jun 11.
Soybean plants can form tripartite symbiotic associations with rhizobia and arbuscular mycorrhizal (AM) fungi, but little is known about effects of co-inoculation with rhizobia and AM fungi on plant growth, or their relationships to root architecture as well as nitrogen (N) and phosphorus (P) availability. In the present study, two soybean genotypes contrasting in root architecture were grown in a field experiment to evaluate relationships among soybean root architecture, AMF colonization, and nodulation under natural conditions. Additionally, a soil pot experiment in greenhouse was conducted to investigate the effects of co-inoculation with rhizobia and AM fungi on soybean growth, and uptake of N and P. Our results indicated that there was a complementary relationship between root architecture and AMF colonization in the field. The deep root soybean genotype had greater AMF colonization at low P, but better nodulation with high P supply than the shallow root genotype. A synergistic relationship dependent on N and P status exists between rhizobia and AM fungi on soybean growth. Co-inoculation with rhizobia and AM fungi significantly increased soybean growth under low P and/or low N conditions as indicated by increased shoot dry weight, along with plant N and P content. There were no significant effects of inoculation under adequate N and P conditions. Furthermore, the effects of co-inoculation were related to root architecture. The deep root genotype, HN112, benefited more from co-inoculation than the shallow root genotype, HN89. Our results elucidate new insights into the relationship between rhizobia, AM fungi, and plant growth under limitation of multiple nutrients, and thereby provides a theoretical basis for application of co-inoculation in field-grown soybean.
大豆植物可以与根瘤菌和丛枝菌根（AM）真菌形成三方共生关系，但对于根瘤菌和 AM 真菌的共接种对植物生长的影响，以及它们与根系结构以及氮（N）和磷（P）供应的关系知之甚少。在本研究中，在田间试验中种植了两种根系结构差异较大的大豆基因型，以评估自然条件下大豆根系结构、AMF 定殖和结瘤之间的关系。此外，还在温室土壤盆栽试验中研究了根瘤菌和 AM 真菌共接种对大豆生长和 N、P 吸收的影响。我们的结果表明，在田间条件下，根系结构和 AMF 定殖之间存在互补关系。深根大豆基因型在低 P 条件下具有更高的 AMF 定殖率，但在高 P 供应下的结瘤情况更好，而浅根基因型则相反。根瘤菌和 AM 真菌在大豆生长上存在一种依赖于 N 和 P 状态的协同关系。在低 P 和/或低 N 条件下，根瘤菌和 AM 真菌的共接种显著增加了大豆的生长，表现为地上部干重增加，同时植物 N 和 P 含量增加。在 N 和 P 充足的条件下，接种没有显著效果。此外，接种的效果与根系结构有关。深根基因型 HN112 比浅根基因型 HN89 从共接种中受益更多。我们的研究结果阐明了在多种养分限制下根瘤菌、AM 真菌和植物生长之间关系的新见解，为共接种在田间大豆中的应用提供了理论依据。
