title: Physiological analysis of common bean (Phaseolus vulgaris L.) cultivars uncovers characteristics related to terminal drought resistance.
abstract: Terminal drought is a major problem for common bean production because it occurs during the reproductive stage, importantly affecting seed yield. Diverse common bean cultivars with different drought susceptibility have been selected from different gene pools in several drought environments. To better understand the mechanisms associated with terminal drought resistance in a particular common bean race (Durango) and growth habit (type-III), we evaluated several metabolic and physiological parameters using two cultivars, Bayo Madero and Pinto Saltillo, with contrasting drought susceptibility. The common bean cultivars were submitted to moderate and severe terminal drought treatments under greenhouse conditions. We analyzed the following traits: relative growth rate, photosynthesis and transpiration rates, stomatal conductance, water-use efficiency, relative water content, proline accumulation, glycolate oxidase activity and their antioxidant response. Our results indicate that the competence of the drought-resistant cultivar (Pinto Saltillo) to maintain seed production upon terminal drought relies on an early response and fine-tuning of stomatal conductance, CO₂ diffusion and fixation, and by an increased water use and avoidance of ROS accumulation.
authors.affiliation: Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Col. Chamilpa, Apdo. Postal 510-3, C.P. 62250, Cuernavaca, Morelos 62210, Mexico.
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Rosales
authors.forename: Edilia
authors.initials: E
authors.lastname: Ocampo
authors.forename: Rocío
authors.initials: R
authors.lastname: Rodríguez-Valentín
authors.forename: Yadira
authors.initials: Y
authors.lastname: Olvera-Carrillo
authors.forename: Jorge
authors.initials: J
authors.lastname: Acosta-Gallegos
authors.forename: Alejandra A
authors.initials: AA
authors.lastname: Covarrubias
mesh_terms: D000222:Adaptation, Physiological; D000429:Alcohol Oxidoreductases / Q000378:metabolism; D000975:Antioxidants / Q000378:metabolism; D018533:Biomass; D002245:Carbon Dioxide / Q000378:metabolism*; D055864:Droughts; D027805:Phaseolus / Q000145:classification / Q000502:physiology*; D010788:Photosynthesis; D010940:Plant Proteins / Q000378:metabolism; D054046:Plant Stomata; D018526:Plant Transpiration; D011392:Proline / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D012639:Seeds; D013045:Species Specificity; D013312:Stress, Physiological; D014867:Water / Q000378:metabolism*
chemical_list: D000975:Antioxidants; D010940:Plant Proteins; D017382:Reactive Oxygen Species; D014867:Water; D002245:Carbon Dioxide; D011392:Proline; D000429:Alcohol Oxidoreductases; C020821:glycollate oxidase