Abscisic acid and catabolites profiling as indicator of different strategies to drought resistance of Patagonian Monte (Argentina) grasses

ANA M. CENZANO, O. MASCIARELLI, MÓNICA B. BERTILLER, AND M. VIRGINIA LUNA

JOURNAL OF PLANT GROWTH REGULATION

SPRINGER

Lugar: Berlin; Año: 2013

0721-7595

Drought affects growth of desert perennial grasses that prevent the desertification and also that are pasture for herbivorous from Patagonian Monte. The identification of physiological traits with play functional roles in adaptation to drought is useful to planning the conservative use of these rangelands. The aim of this study was to evaluate the effect of drought on i) vegetative biomass accumulation, ii) endogenous levels of abscisic acid (ABA) and catabolites (phaseic acid-PA, dihydrophaseic acid-DPA and abscisic acid conjugated with glucose ester-ABA-GE), iii) total carotenoids concentration and iv) compare these traits between grasses and plant organs. P. ligularis and P. speciosa were submitted to two soil water levels from August 2009 to December 2010. Drought significantly decreased vegetative biomass, increased ABA and DPA levels in green leaves of P. ligularis and P. speciosa respectively. In roots of P. ligularis drought increased ABA and decreased DPA. In green and senescent leaves the ABA accumulation was highest in P. ligularis; whilst DPA was highest in P. speciosa. Roots of P. ligularis had more ABA and PA than P. speciosa. Drought increased carotenoids in senescent leaves of both species. Our results show a differential ABA metabolism (synthesis and/or catabolism) in grasses of Patagonian Monte with contrasting drought resistance and life-history strategies. The highest ABA level was found in the mesophytic species P. ligularis and the lower in the xerophytic species P. speciosa revealing that the hormone profiling of each species correlates with the strategies to drought resistance for each plant functional type.