Influence ofPseudomonas syringaeR25 andP. putidaR105 on the growth and N2fixation (acetylene reduction activity) of pea (Pisum sativumL.) and field bean (Phaseolus vulgarisL.)
✍ Scribed by J. R. Freitas; V. V. S. R. Gupta; J. J. Germida
- Publisher
- Springer
- Year
- 1993
- Tongue
- English
- Weight
- 651 KB
- Volume
- 16
- Category
- Article
- ISSN
- 0178-2762
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✦ Synopsis
The effects of inoculating field peas (Pisum sativum L.) with Rhizobium leguminosarum and field beans (Phaseolus vulgaris L.) with R. phaseoli, alone or in combination with Pseudomonas syringae R25 and/or R putida R 105, were assessed under gnotobiotic conditions in growth pouches and in potted soil in a growth chamber. Inoculation of peas with P. syringae R25 or P. putida R105 alone had no effect on plant growth in pouches. In soil, however, the isolate R25 inhibited nitrogenase activity (as assessed by acetylene reduction assay) of nodules formed by indigenous rhizobia; strain R 105 stimulated pea seedling emergence and nodulation. P. syringae R25 inhibited the growth of beans in either plant-growth system. R putida R 105, however, had no effects on beans in pouches, but reduced plant root biomass and nodulation by indigenous rhizobia in soil. Coinoculation of pea seeds with R. leguminosarum and either of the pseudomonads significantly (P<0.01) increased shoot, root, and total plant weight in growth pouches, but had no effect in soil. Co-inoculation of field beans with R. phaseoli and P. putida R 105 had no effects on plant biomass in growth pouches or in soil, but the number of nodules and the acetylene reduction activity was significantly (P< 0.01) increased in the soil. In contrast, co-inoculation of beans with rhizobia and P. syringae R25 had severe, deleterious effects on seedling emergence, plant biomass, and nodulation in soil and growth pouches. Isolate R25 was responsible for the deleterious effects observed. Although plant growth-promoting rhizobacteria may interact synergistically with root-nodulating rhizobia, the PGPR selected for one crop should be assessed for potential hazardous effects on other crops before being used as inoculants.