Resumen de Gas exchange and mass distribution of the cowpea (Vigna unguiculata [L.] Walp.) under water deficit
Carlos Enrique Cardona Ayala, Alfredo de Jesús Jarma Orozco, Hermes Araméndiz Tatis, Marvin José Perneth Montaño, Cesar A. Vergara Cordoba
Drought tolerance is important for the survival and productivityof plants in environments where drought periods areincreasing as a result of climate variability attributable tonatural causes and climate change caused by human activities.The objective of this study was to evaluate the dynamicsof photosynthesis (A), stomatal conductance (gs) and intrinsicwater-use efficiency (WUE=A/gs) as a function of soil moisturecontent over a period of drought and the post-stress recoveryof 14 cowpea genotypes. The studied genotypes tolerated soilmoisture tensions close to -2 Mpa with no permanent wilting.Starting at a soil hydric potential of -0.7 MPa, decreases inphotosynthesis (A), stomatal conductance (gs) and transpiration(E) were evident, as well as an increase in A/gs, whichvaried by genotype. Estimating with regression models allowedfor the discrimination of the degrees of drought tolerancebetween the cultivars. At 4 days after resuming hydration, nosignificant differences were found between the means of A, gs,A/gs and E, suggesting drought tolerance in all genotypes. Thegenotypes: L-047 and L-034 conserved between 4 and 6 leaves,displaying the highest delayed leaf senescence during drought.Furthermore, they presented the highest biomass at 16 dayspost-stress recovery.
