Morphological and physiological responses during the post-flooding period of Salix matsudana Koidz.

RODRÍGUEZ MARÍA EMILIA; MONTEOLIVA SILVIA; MOZO IRINA; LUQUEZ VIRGINIA M.C.

Buenos Aires

Simposio; VII IUFRO International Poplar Symposium; 2018

The morphological and physiological responses of willowsto flooding have been characterized, but not much is known about theirresponses during the post-flooding period. After the end of the stress episode,plants may modify some traits to compensate for the biomass loss duringflooding. The aim of this work was to analyze the post-flooding responses ofwillows under two different depths of floodwater. The hypothesis was that thephysiological responses in the post-flooding period would be differentaccording to the floodwater depth.Cuttings of clone Salixmatsudana NZ692 were planted in pots in a greenhouse. The experimentstarted when the plants were 2 months old with the following treatments: plantswatered to field capacity (C); plants flooded 10 cm above soil level (F10) andplants flooded 40 cm above soil level (F40). There were 22 repetitions for eachtreatment. The flooding episode lasted for 30 days and was followed by arecovery period of 28 days (post-flooding period).During the post-flooding period, the photosyntheticrate and total leaf area were significantly higher in F40 than in C and F10treatments. However, the relative growth rate in height was not significantlydifferent between the treatments. This could be because flooding increased rootmortality, and in the post flooding period the root-to-shoot ratio was still significantlylower in F40 compared with C and F10. It is likely that part of thecarbohydrates in F40 were used to develop new roots to compensate for thelosses, instead of increasing the growth in height. In addition, F40 had alower number of xylem vessels with higher diameter compared with C treatment,but this did not affect significantly the xylem hydraulic conductivity (eitherexpressed per unit length, per unit xylem area or per unit leaf area).From our results, it is clear that the depth of thefloodwater not only causes different responses during flooding. The effectspersist into the post flooding recovery period, affecting the growth and physiologyof willows once the stress episode has ended.