Chlorophyll a fluorescence of Bertholletia excelsa Bonpl. plantations under thinning, liming, and phosphorus fertilization

Phosphorus (P) fertilization and liming can reduce negative effects caused by a sudden increase in light availability after thinning of forest plantations. In this study, immediately after thinning, photochemical performance (quantum yield of PSII and performance index) decreased, however, liming and P fertilization reduced the negative effects caused by thinning and accelerated the recovery of Bertholletia excelsa trees. After thinning, the remaining trees increased J-I phase with the formation of a positive K-band which occurred exclusively in unfertilized (no liming or no P) individuals. Additionally, enhanced effective dissipation (DI0/RC) values (140%) were found in individuals without liming or P after thinning, while plants under liming and P increased DI0/RC values by 47 and 79%, respectively. Photochemical performance of B. excelsa was positively correlated to iron, zinc, and manganese. Thus, P fertilization and liming are recommended for alleviating the stress caused by high irradiance after thinning in B. excelsa plantations.