Physiological changes in bean cultivadas con riego reducido y aplicaciones foliares de PectiMorf[R]

The effect of foliar applications of PectiMorf[R] was studied in bean plants (Phaseolus vulgaris L.) cultivated under two irrigation variants. For this, 12 concrete containers were planted with the cultivar "Tomeguin 93". The irrigation consisted of applying 100 and 50 % of the ETc (standard evapotranspiration of the crop) and the PectiMorf[R] foliar applications were 150 mg [ha.sup.-1] at 20 and 35 days after sowing giving rise to the following four treatments: T1-100 % ETc, considered as control treatment. T2- 100 % ETc + P (P = PectiMorf[R] application at 20 and 35 DAS) T3- 50 % ETc + P and T4- 50 % ETc, considered as stress treatment. Seven days after the PectiMorf[R] applications (28 and 43 DAS) were evaluated, the soil moisture content and different physiological indicators such as growht in dried biomass, leaf water potential ([PSI]f), actual osmotic potential ([PSI]s), osmotic potential at maximum turgor ([PSI]100s) and stomatal conductance (gs). In addition, the water potential of the soil at the level of the soil-root interfaces ([PSI]r) and the contribution of dehydration to changes in potential osmotic [DELTA][PSI] ss were calculated. The results showed a positive effect of the foliar applications of PectiMorf[R] in the improvement of plants water status in both irrigation variants. Key words: bean, plant water relations, water stress. Se estudio el efecto de aplicaciones foliares de PectiMorf[R] en plantas de frijol cultivadas bajo dos variantes de riego, Se sembraron con el cultivar "Tomeguin 93" 12 canaletas de hormigon. El riego consistio en aplicar el 100 y el 50 % de la ETc (Evapotranspiracion estandar del cultivo) y las aplicaciones foliares de PectiMorf[R] fueron de 150 mg [ha.sup.-1], a los 20 y 35 dias despues de la siembra (DDS), dando lugar a los siguientes tratamientos: T1-100 % ETc, considerado como tratamiento control; T2- 100 % ETc + P (P= aplicacion de PectiMorf[R] a los 20 y 35 DDS); T3- 50 % ETc + P y T4-50 % ETc, considerado, este ultimo, como tratamiento estres. A los siete dias de realizadas las aplicaciones de PectiMorf[R] (28 y 43 DDS) se evaluo el contenido de humedad del suelo y los diferentes indicadores fisiologicos, como son: el crecimiento en biomasa seca, el potencial hidrico foliar ([PSI]f), el potencial osmotico actual ([PSI]s), el potencial osmotico a maxima turgencia ([PSI]100s) y la conductancia estomatica (gs). Ademas, se calculo el potencial hidrico del suelo a nivel de la interface suelo-raiz ([PSI]r) y la