Floodwater Depth Causes Different Physiological Responses during Post-Flooding in Willows

MOZO IRINA; RODRIGUEZ MARIA EMILIA; MONTEOLIVA SILVIA; LUQUEZ VIRGINIA M.C.

Frontiers in Plant Science

Frontiers Media

Año: 2021 vol. 12 p. 1 - 12

Willows are widely planted in areas under risk of flooding. Thephysiological responses of willows to flooding have been characterized, but littleis known about their responses during the post-flooding period. After the endof the stress episode, plants may modify some traits to compensate for thebiomass loss during flooding. The aim of this work was to analyze thepost-flooding physiological responses of willow under two different depths of stagnantfloodwater.Cuttings of Salix matsudana NZ692 clone were planted in pots in agreenhouse. The experiment started when the plants were 2 months old withthe following treatments: Control plants (watered to field capacity); plants partiallyflooded 10cm above soil level (F10) and plants partially flooded 40cm abovesoil level (F40). The flooding episode lasted 35 days and was followed bya recovery period of 28 days (post-flooding period). After the floodingperiod, height, diameter and total biomass were higher in F10, while F40 plantsshowed an increase in plant adventitious root production and leaf nitrogencontent.During the post-flooding period, the photosynthetic rate, nitrogen, chlorophylland soluble sugar contents were significantly higher in leaves of F40 than in Controland F10 treatments. Stomatal conductance and specific leaf area were higher inthe previously flooded plants compared to Control treatment. Plants from F10treatments showed a higher growth in height, root-to-shoot ratio, and carbonisotope discrimination than F40, while the opposite occurred for growth indiameter, vessel size and leaf area.We conclude that depth of floodwater not only causes different responsesduring flooding, but that its effects are also present in the post-floodingrecovery period, affecting the growth and physiology of willows once the stressepisode has ended. Even when flooding impacted growth negatively in F40, in thepost-flooding period these plants compensated by increasing the photosynthetic rate,plant leaf area and xylem vessel size. Willows endurance to flooding is theresult of both responses during flooding, and plastic responses duringpost-flooding.