Physiological responses to alternative flooding and drought stress episodes in two willow (Salix spp.) clones.

DOFFO, GUILLERMO; MONTEOLIVA SILVIA; RODRÍGUEZ MARÍA EMILIA; LUQUEZ VIRGINIA M.C.

CANADIAN JOURNAL OF FOREST RESEARCH

NATL RESEARCH COUNCIL CANADA-N R C RESEARCH PRESS

Lugar: Otawa; Año: 2017 vol. 47 p. 174 - 182

0045-5067

Climate change will increase the occurrence of flash floods as a consequence of extreme rain events, creating alternateperiods of drought and flooding during the growing season. We analyzed the responses of two willow clones with contrasting responses to flooding (clone B:Salix matsudana x Salix alba hybrid; clone Y: Salix alba) to different combinations ofstress treatments: continuous flooding or drought for six weeks, or cyclictreatments of two weeks of stress separated by two weeks of watering at fieldcapacity. Drought reduced growth, stomatal conductance and total leaf area inboth clones, but flooding did not. Flooding reduced the root/shoot ratio inboth clones. The hydraulic conductivity of the main stem was significantlyreduced by drought only in clone Y. The area of the vessels was decreased byboth drought and flooding, but the number was increased only by drought. The occurrence of drought before flooding reduced thevessel area, but the opposite treatment did not. An episode of drought afterone of flooding is more stressful than the opposite situation, especially forclone Y that could not adjust its water transport capacity during the droughtperiod.