Effect of salinity on nodulation, nitrogen fixation and growth of common bean (Phaseolus vulgaris) inoculated with rhizobial strains isolated from the Haouz region of Morocco

Abstract

This study compared growth, nodulation, nitrogen fixation, and nodular enzyme activities in response to salinity in some common bean-rhizobia symbiotic combinations. Seeds of Paulista and Efequince, two varieties of the common bean (Phaseolus vulgaris) were germinated and seedlings were transferred to pots containing vermiculite inoculated with the reference Rhizobium strain CIAT899 or with RhM11 or RhM14, two local strains. Plants were grown in a temperature-controlled glasshouse at 28°C and irrigated with a nutrient solution without NaCl (control) or supplemented with 25 mM NaCl (stressed). Plants were harvested at the flowering stage. The results showed that in controls, inoculation with RhM11 improved plant and nodule growth compared with those inoculated with RhM14 and CIAT 899. NaCl treatment generally had a negative affect on plant and nodule growth. Under the saline treatment, symbiotic nitrogen fixation was not significantly affected in the CIAT899-Paulista, CIAT899-Efequince and RhM11-Paulista combinations. Plant mineral nutrition was negatively affected under salt treatment for all of the tested symbiotic combinations. Inoculation with CIAT899 and RhM11 conferred more plant tolerance to salinity than inoculation with RhM14. The nodular phosphoenolpyruvate carboxylase (PEPC) and malate dehydrogenase (MDH) exhibited higher activities and were less affected by salinity in plants inoculated with the reference strain CIAT899 than those inoculated with local strains. We conclude that plants inoculated with CIAT899 and RhM11 showed more salinity stress tolerance than those inoculated with RhM14.

Cultivation-Based and Molecular Assessment of Bacterial Diversity in the Rhizosheath of Wheat under Different Crop Rotations

“…Sequences that showed >97% similarity with previously reported PGPR genera were grouped. Letter ‘a’ represents nitrogen fixing genera, ‘b’ represents IAA producing genera and ‘c’ represents phosphate solubilizing bacterial genera [ 18 ], [ 19 ], [ 20 ], [ 21 ], [ 42 ], [ 43 ], [ 44 ], [ 46 ], [ 47 ], [ 51 ], [ 52 ], [ 53 ], [ 54 ], [ 55 ], [ 56 ], [ 57 ], [ 58 ], [ 59 ],…”

Effet de la salinité sur la croissance et la production de biomasse de deux provenances de <i>Jatropha curcas</i> L. cultivés en serre

“…La salinité du sol provoque une diminution du potentiel osmotique de la solution du sol, le déséquilibre nutritionnel et ou la toxicité des ions (Zhu, 2003;Turan et al, 2010). C'est l'un des principaux facteurs environnementaux qui limitent la croissance et le développement des plantes (Ghoulam et al, 2002;Faghire et al, 2011). Plusieurs études ont montré que la croissance en hauteur (Rui et al, 2009;Memon et al, 2010), la production de biomasse des tiges et des racines (Ashraf and Ali, 2008;Shahbaz et al, 2010) sont négativement affectées par l'accroissement de la salinité.…”

N2 fixation ability of different dry bean genotypes

“…The other important environmental factor affecting SNF is salinity. In the saltsensitive species, like common bean (Faghire et al 2011), salt stress can suppress crop productivity due to reduction in plant growth and the capacity of SNF (Delgado et al 1993), because of weaker symbiotic association between plants and rhizobia (Georgiev and Atkins 1993).…”