Ability to recover overrides the negative effects of flooding on growth of tropical grasses Chloris gayana and Panicum coloratum

Abstract

This study assessed the flooding tolerance of the tropical grasses Chloris gayana Kunth and Panicum coloratum L. at different times of the year: (i) late winter flooding for 50 days (WF), (ii) early spring flooding (SF) for 20 days, and (iii) long-term flooding covering both periods (WF + SF, 70 days). A growth period under well-watered conditions was allowed after each flooding event to assess recovery of plant species. Plants were harvested after each flooding event and at the end of the recovery period. Panicum coloratum had higher tolerance to WF than C. gayana. Treatment WF did not affect biomass in P. coloratum, whereas it reduced biomass of flooded plants by 38% in C. gayana. Treatment SF did not differentiate the species for tolerance; both registered moderate reduction in their growth (20–30%). Under WF + SF, C. gayana showed additional reduction in its growth over that observed when subjected separately to either WF or SF, whereas P. coloratum did not. Both species displayed remarkably fast recovery from flooding when temperatures rose during early summer, attaining biomass equivalent to that of non-flooded plants 1 month after water subsided. Therefore, although P. coloratum appears slightly more tolerant during flooding than C. gayana, both species are promising for introduction in temperate lowland grasslands.