Clonal variation in photosynthesis, foliar nutrient concentrations, and photosynthetic nutrient use efficiency in a Brazil nut (Bertholletia excelsa) plantation

Abstract

Bertholletia excelsa Bonpl. (Lecythidaceae) has been used for reclaiming degraded areas and in commercial plantations in Amazonia. In this study, we analyzed five clones of B. excelsa (Aruãna [ARU], 609, 606, Manuel Pedro, and Santa Fe) in a commercial plantation to elucidate the responses of specific leaf area (SLA), photosynthetic rates per unit mass (PNmass), foliar nutrient concentrations, and photosynthetic nutrient use efficiency [P(element)UE] in sun and shade leaves during high and low precipitation. Clone 606 had foliar K concentrations between 24 and 50% higher than those in all other clones. Clones ARU, 609, and 606 were most efficient in the use of all leaf nutrients. ARU showed the best performance in primary macronutrient use efficiencies (nitrogen, phosphorus [P], and potassium [K]). Shade leaves preferentially accumulated P and K, whereas sun leaves preferentially accumulated manganese. All clones had higher SLA, PNmass, and foliar P and K concentrations during low precipitation. This effect may partially be related to leaf age because development of new leaves in B. excelsa takes place at the beginning of the low-precipitation period. The results provide information to guide selection of B. excelsa clones for nutrient-poor soils in Amazonia.