RESPONSES TO DIFFERENT LEVELS OF FLOODING IN WILLOWS (SALIX SPP)

RODRÍGUEZ MARÍA EMILIA; DOFFO, GUILLERMO; CERRILLO TERESA; LUQUEZ, VIRGINIA

Berlín

Congreso; IPC 2016; 2016

IPC FAO

In the next decades, there will bean increased demand of biomass for energy from willows (Salix spp). To meet these demands, plantations need to beestablished in marginal areas not used in agriculture, like flood-prone lowlandareas. Climate change will increase the frequency of extreme rain events,causing flash flooding episodes, so it is importantto breed willow clones that can survive these conditions. For willows plantations, theestablishment phase is a crucial point, when the vulnerability to stresses ishigher because the cuttings are still developing a root system. A flooding episode during this early period can have a negative effect upon plants.In this work, we analyzed theresponses of eight willows genotypes to flooding. Amongthese genotypes were individuals of Salixalba (3 clones), S. matsudana (2clones), S. amygdaloides (1 clone)and two clones originated from open pollination of a S. matsudana x S. nigra mother. Most clones were used as parents inbreeding programs developed by INTA, in consequence is important to know theirresponse to flooding. The treatments were: Control (watered normally); partialflooding (submerged in water 10 cm above soil surface); deep flooding(submerged in water 45 cm above soil surface). The cuttings were planted inpots outdoors and the treatments started when the plants where 2 months old,lasting for 3 weeks. The variables measured where: height, diameter, number ofleaves, leaf nitrogen content, stomatal conductance, and total biomass and itspartition between different plant organs. The deep flooding treatment caused ahigher growth reduction than partial flooding in most clones, either measuredas height, diameter or total biomass. Both flooding treatments reducedsignificantly the root-to-shoot ratio compared to control plants. The partialflooding treatment caused a decrease in foliar nitrogen content compared tocontrol plants, while the deep flooding treatment increased the leaf nitrogencontent. After 3 weeks of flooding, once the water drained, the plants thatunderwent deep flooding treatment increased their stomatal conductance comparedto the control and partial flooding treatment.       The treatments changed plant andleaf traits in different ways according to the deep of the floodwater. Thesechanges, especially in root-to-shoot ratio and leaf nitrogen content, couldhave lasting effects on photosynthesis and growth recovery in the post-floodingperiod. Clones which maintain higher root biomass and nitrogen leaf contentprobably will have a faster recovery once the flooding has passed.