POPLARS AND WILLOWS RESPONSES TO FLOODING STRESS

RODRÍGUEZ MARÍA EMILIA; LUQUEZ VIRGINIA M.C.

Poplars and willows: cultivation, applications and environmental benefits

Nova Science Publishers

Lugar: New York; Año: 2016; p. 103 - 130

Different species of the genus Populus are of great economic importanceas major sources of timber, pulp and fiber. Salixspecies have become very important sources of biomass for bioenergy. Both arecharacterized by their fast-growing trees, being asexually propagated, and havingseveral species growing in riparian areas prone to flooding.Floodingis a common stress factor in both natural and planted forestry systems, and itchallenges plant growth and fitness. Climate change models predict an increasein the frequency of flooding events globally due to altered precipitationpatterns which will cause extreme rainfall events. This would make floodingstress a major environmental threat for plants.Floodingtolerance is related to the ability of the plant to develop adaptive structuresto cope with the lack of oxygen caused by the excess of water in the soil. Thedevelopment of aerenchyma, hypertrophied lenticels and adventitious rootsenables the plant to maintain a greater root biomass and foliar area during theepisode of stress. This facilitates the possibility of having better stomatalopening and photosynthetic capacity, therefore maintaining a greateravailability of photoassimilates. These adaptive features, plus the antioxidantcapacity to remove toxic species generated during the flooding period andduring the post-flooding reaeration, would ensure the rapid restoration foroptimum plant growth after the stress episode.A betterunderstanding of the responses to flooding in poplar and willows could serve asa basis for classical breeding programs or biotechnological developmentsdesigned to increase flooding tolerance. The generation of information can alsobe helpful for the management of wetland ecosystems. This review summarizes theresearch on morphological, anatomical, physiological and molecular responses toflooding of species belonging to the Salicaceae family.