Abstract
Grafting studies involving Williams 82 (normally nodulating) and NOD1-3 (hypernodulating) soybean (Glycine max [L.] Merr.) lines and Lablab purpureus were used to evaluate the effect of shoot and root on nodulation control and plant growth. A single- or double-wedge graft technique, with superimposed partial defoliation, was used to separate signal control from a photosynthate supply effect. Grafting of hypernodulated soybean shoots to roots of Williams 82 or L. purpureus resulted in increased nodule numbers. Grafting of two shoots to one root enhanced root growth in both soybean genotypes, whereas the nodule number was a function of shoot genotype but not of the photosynthetic area. In double-shoot, single-root-grafted plants, removing trifoliolate leaves from either Williams 82 or NOD1-3 shoots decreased root and shoot dry matter, attributable to decreased photosynthetic source. Concurrently, Williams 82 shoot defoliation increased the nodule number, whereas NOD1-3 shoot defoliation decreased the nodule number on both soybean and L. purpureus roots. It was concluded that (a) soybean leaves are the dominant site of autoregulatory signal production, which controls the nodule number; (b) soybean and L. purpureus have a common, translocatable, autoregulatory control signal; (c) seedling vegetative growth and nodule number are independently controlled; and (d) two signals, inhibitor and promoter, may be involved in controlling legume nodule numbers.
Full Text
The Full Text of this article is available as a PDF (725.6 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Bhuvaneswari T. V., Bhagwat A. A., Bauer W. D. Transient susceptibility of root cells in four common legumes to nodulation by rhizobia. Plant Physiol. 1981 Nov;68(5):1144–1149. doi: 10.1104/pp.68.5.1144. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Caetano-Anollés G., Gresshoff P. M. Alfalfa Controls Nodulation during the Onset of Rhizobium-induced Cortical Cell Division. Plant Physiol. 1991 Feb;95(2):366–373. doi: 10.1104/pp.95.2.366. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Caetano-Anollés G., Gresshoff P. M. Plant genetic control of nodulation. Annu Rev Microbiol. 1991;45:345–382. doi: 10.1146/annurev.mi.45.100191.002021. [DOI] [PubMed] [Google Scholar]
- Delves A. C., Mathews A., Day D. A., Carter A. S., Carroll B. J., Gresshoff P. M. Regulation of the soybean-Rhizobium nodule symbiosis by shoot and root factors. Plant Physiol. 1986 Oct;82(2):588–590. doi: 10.1104/pp.82.2.588. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Gremaud M. F., Harper J. E. Selection and initial characterization of partially nitrate tolerant nodulation mutants of soybean. Plant Physiol. 1989 Jan;89(1):169–173. doi: 10.1104/pp.89.1.169. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Heron D. S., Pueppke S. G. Regulation of nodulation in the soybean-Rhizobium symbiosis : strain and cultivar variability. Plant Physiol. 1987 Aug;84(4):1391–1396. doi: 10.1104/pp.84.4.1391. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kosslak R. M., Bohlool B. B. Suppression of nodule development of one side of a split-root system of soybeans caused by prior inoculation of the other side. Plant Physiol. 1984 May;75(1):125–130. doi: 10.1104/pp.75.1.125. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Pierce M., Bauer W. D. A rapid regulatory response governing nodulation in soybean. Plant Physiol. 1983 Oct;73(2):286–290. doi: 10.1104/pp.73.2.286. [DOI] [PMC free article] [PubMed] [Google Scholar]