Flooding tolerance of Calophyllum brasiliense Camb. (Clusiaceae): morphological, physiological and growth responses

Calophyllum brasiliense Camb. (Clusiaceae) is a tree of swampy areas of the coastal Restinga in southeastern Brazil (a coastal sand-plain scrub and forest formation). To elucidate possible adaptive strategies that enable this species to occupy areas subjected to seasonal or perennial waterlogging, growth characters such as shoot height, biomass production, leaf expansion, new leaf development, stem diameter, carbon dioxide assimilation rate, stomatal conductance, chlorophyll concentration and fluorescence were studied in controls and plants flooded for up to 150 days. Although flooded plants kept incorporating carbon all through the experiment, their assimilation rate and growth rate were lower than control, non-flooded plants. Injuries such as leaf senescence and abscision were not observed but some flooded plants showed signs of leaf chlorosis. In view of its capacity to maintain carbon assimilation and growth during the treatment, C. brasiliense can be classified as flood-tolerant tree. Flooding induced hypertrophy of lenticels, increased stem diameter and development of adventitious roots. These characteristics of C. brasiliense are most probably responsible for its survival and success in naturally seasonally flooded areas, inhospitable environments for most tree species. Reduction in total chlorophyll concentration was probably the main cause of reduced carbon dioxide assimilation rate. Based on the results we recommend C. brasiliense for rehabilitation of native vegetation in flood-prone areas.