title: Physiological traits related to terminal drought resistance in common bean (Phaseolus vulgaris L.).
abstract: BACKGROUND
  A major problem in common bean (Phaseolus vulgaris L.) agriculture is the low yield due to terminal drought. Because common beans are grown over a broad variety of environments, the study of drought-resistant genotypes might be useful to identify distinctive or common mechanisms needed for survival and seed production under drought.
  
  
  RESULTS
  In this study the relationship between terminal drought resistance and some physiological parameters was analysed using cultivars contrasting in their drought response from two different gene pools. Trials were performed in three environments. As expected, drought treatments induced a decrease in leaf relative humidity and an increase in leaf temperature; however, when these parameters were compared between susceptible and resistant cultivars under optimal irrigation and drought, no significant differences were detected. Similar results were obtained for chlorophyll content. In contrast, analysis of relative water content (RWC) and stomatal conductance values showed reproducible significant differences between susceptible and resistant cultivars grown under optimal irrigation and drought across the different environments.
  
  
  CONCLUSIONS
  The data indicate that drought-resistant cultivars maximise carbon uptake and limit water loss upon drought by increasing stomatal closure during the day and attaining a higher RWC during the night as compared with susceptible cultivars, suggesting a water balance fine control to achieve enough yield under drought.
authors: Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Col. Chamilpa CP 62210, Cuernavaca, Morelos, Mexico.
authors: Miguel A
authors: MA
authors: Rosales
authors: Sonia M
authors: SM
authors: Cuellar-Ortiz
authors: María
authors: M
authors: de la Paz Arrieta-Montiel
authors: Jorge
authors: J
authors: Acosta-Gallegos
authors: Alejandra A
authors: AA
authors: Covarrubias
mesh_terms: D015415:Biomarkers / Q000378:metabolism; D057486:Carbon Cycle; D002734:Chlorophyll / Q000096:biosynthesis; D018556:Crops, Agricultural / Q000254:growth & development* / Q000378:metabolism; D055864:Droughts; D006358:Hot Temperature / Q000009:adverse effects; D008800:Mexico; D027805:Phaseolus / Q000254:growth & development* / Q000378:metabolism; D018515:Plant Leaves / Q000254:growth & development* / Q000378:metabolism; D015203:Reproducibility of Results; D012639:Seeds / Q000254:growth & development* / Q000378:metabolism; D013045:Species Specificity; D013499:Surface Properties; D014867:Water / Q000378:metabolism*
chemical_list: D015415:Biomarkers; D014867:Water; D002734:Chlorophyll