INVESTIGADORES
LUQUEZ Virginia Martha Cristina
congresos y reuniones científicas
Título:
Willows responses to alternate periods of drought and flooding stress
Autor/es:
DOFFO, GUILLERMO; RODRÍGUEZ MARÍA EMILIA; MONTEOLIVA SILVIA; CERRILLO TERESA; LUQUEZ VIRGINIA M.C.
Lugar:
Vancouver
Reunión:
Simposio; IPS VI; 2014
Institución organizadora:
IUFRO
Resumen:
In the next years, climate
change will increase the occurrence of flash flooding as a consequence of
extreme rain events. In certain areas of Argentina, this fact will create
alternate periods of drought and flooding during the growing season. To develop
willow plantations in these areas, it is necessary to gain a better understanding
of the physiology under these particular combinations of stresses. In this
work, we explored the responses of two willow clones to different combinations
of stress treatments: continuous flooding or drought for 6 weeks, or cyclic
treatment of 2 weeks of stress separated by 2 weeks of normal watering.
The type of stress and the
order of occurrence modified in different ways the growth in height, dry matter
partitioning, gas exchange, leaf area dynamics and shoot hydraulic
conductivity. Above ground growth was severely reduced by drought in both
clones, either in continuous or cyclic treatment. A cycle of drought followed
by flooding reduced growth in a lesser extent than the opposite situation. The
clones responded to the flooding followed by drought combination in a different
way. One clone experienced a marked reduction in shoot hydraulic conductivity
that was ten times lower than in control plants, combined with and extensive
defoliation. In the other clone, the reduction of hydraulic conductivity was
not significant, and it experienced a lesser degree of defoliation. It is
likely that the extensive defoliation is a consequence of the inability to
maintain an adequate water supply to the leaves because of the occurrence of
severe embolism. The higher susceptibility to embolism correlates with the
occurrence of fewer vessels with a higher lumen.
The two willow clones analyzed in this work had
different strategies to cope with the occurrence of drought episodes. One clone
experiences an extensive defoliation and a rapid resuming of growth after the
end of the stress, while the other maintained the leaf area at the expense of growth