| Abstract: | Larqué-Saavedra, A., Rodriguez, M. T., Trejo, C. andNava, T. 1985. Abscisic acid accumulation and water relationsof four cultivars of Phaseolus vulgaris L. under drought.—J.exp. Bot 36: 1787–1792. Plants of four cultivars of Phaseolus vulgaris L. differingin drought resistance were grown in pots under greenhouse conditionsand prior to flowering water was withheld from the pots untilthe mid-day transpiration rate reached values below 1.0 µgH2O cm–2 s–1 (designated the ‘drought’stage). At this point leaves were harvested on 3 or 4 occasionsover 24 h to determine the abscisic acid (ABA) concentration,total water potential (  ), solute potential (1) and turgor potential(p). Results showed that values of , 1, and p differed between cultivarswhen they reached the ‘drought’ stage. The stomatalsensitivity to changes in and p, was as follows: Michoacán12A3 > Negro 150 Cacahuate 72 > Flor de Mayo. These datacorrelated well with the pattern of drought resistance reportedfor the cultivars. ABA accumulation at the ‘drought’ stage differedbetween cultivars at each sampling time, but overall differencesin ABA level between cultivars were not significant. ABA levelsdid not, therefore, correlate with the drought resistance propertiesreported for the cultivars. Results are discussed in relationto and hour of the day when bean samples were taken for ABAanalysis. Key words: Phaseolus vulgaris L., drought resistance, abscisic acid |
