Photosynthesis and Survival of Young Carpotroche brasiliensis Endl. (Achariaceae) Plants Subjected to Flooding

Abstract

Abstract Carpotroche brasiliensis is a native tree of the Brazilian Atlantic Forest with potential economic value for cultivation in agroforestry systems. We conducted an experiment to determine the photosynthetic and survival responses of young C. brasiliensis plants to electrochemical changes in flooded soils as an indication of their flood tolerance and potential for cultivation in flood-prone areas. Soil flooding decreases the reduction–oxidation potential (redox) potential (Eh), pH, and electrical conductivity (Ec) of the soil, with subsequent recovery of the pH and Ec. Decreases in Eh negatively affect net photosynthesis (A). In flooded soil, decreased A was associated with decreased stomatal conductance (gs) and after 21 days was also associated with decreases in the instantaneous carboxylation efficiency (A/Ci) and potential quantum yield of photosystem II (Fv/Fm). Although flooded C. brasiliensis seedlings developed morphological structures known to increase flood tolerance, this was not enough to prevent severe signs of flooding stress. After 21 days of flooding, flooded plants were unflooded, and 17 days after plants were removed from flood, 90 percent of the unflooded plants died. Our results demonstrate that young plants of C. brasiliensis are suitable for planting in agroforestry systems only in areas with well-drained soils.