Symbiotic performance, nitrogen flux and growth of lima bean (Phaseolus lunatus L.) varieties inoculated with different indigenous strains of rhizobia

• Published in: Symbiosis (Philadelphia, Pa.) Vol. 73; no. 2; pp. 117 - 124
• Main Authors: da Costa Neto, Vicente Paulo, Mendes, Janaina Barros Siqueira, de Araújo, Ademir Sérgio Ferreira, de Alcântara Neto, Francisco, Bonifacio, Aurenivia, Rodrigues, Artenisa Cerqueira
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.10.2017; Springer Nature B.V
• Subjects: Biomedical and Life Sciences; Bradyrhizobium; Chlorophyll; Conservation; Developmental Biology; Ecology; Evolutionary Biology; Host plants; Legumes; Life Sciences; Microbiology; Nitrogen; Nitrogen fixation; Nutrient solutions; Phaseolus lunatus; Plant Sciences; Root nodules; Symbiosis; Growth; Diazotrophs; Nitrogen fixation efficiency
• ISSN: 0334-5114; 1878-7665
• DOI: 10.1007/s13199-017-0475-6

Legumes, such as lima bean, can form symbiotic relationships with rhizobia and can therefore grow in nitrogen-poor soils. Lima bean varieties in symbiosis with indigenous rhizobia were evaluated for their symbiotic performance over three harvest periods. Four indigenous rhizobial strains (ISOL-16, ISOL-18, ISOL-19 or ISOL-35) were isolated from soil samples in lima bean fields and used separately to inoculate two lima bean varieties (‘boca de moça’ and ‘branca’). Uninoculated, unfertilized plants were used as controls, and uninoculated, nitrogen-supplied plants were used as the nitrogen control. All inoculated plants and the uninoculated control were cultivated using nitrogen-free nutrient solutions in the greenhouse. As expected, the uninoculated plants did not develop nodules on their root systems and were inferior in all evaluated parameters. The lima bean nodulated by Bradyrhizobium exhibited growth variables, nodules parameters, and nitrogen flux values superior to those of plants inoculated with Rhizobium . The highest total chlorophyll values were recorded in lima bean inoculated with Bradyrhizobium , confirming that these plants had the greenest leaves and likely have superior photosynthetic efficiency – a hypothesis supported by the greater growth exhibited by these plants. Nitrogen fixation efficiency was superior in lima bean nodulated by Bradyrhizobium , indicating that this microbe possesses a greater ability to fix nitrogen and provide it continuously to the host plant. The symbiosis between lima bean and Bradyrhizobium sp. ISOL-18 displayed the best values with respect to carbon and nitrogen flow. We conclude that Bradyrhizobium is the most effective at establishing an efficient and successful symbiotic relationship with lima bean and emphasize the potential value of Bradyrhizobium strains as inoculants in lima bean cultivation.