High aluminum availability may affect Styrax camporum, an Al non-accumulating species from the Brazilian savanna

Abstract

In the Cerrado vegetation, generally known as ‘Brazilian savanna’, aluminum (Al) accumulating and non-accumulating plants coexist, growing on soils that are acidic, poor in nutrients and rich in Al. Differing from Al-sensitive species, these plants are not expected to experience Al injuries. Using Styrax camporum, a non-accumulating plant, we recorded biometric variations in leaves, shoots and roots of young plants exposed to 0 and 1480 μM Al in a nutrient solution. Photosynthetic responses were measured bi-weekly over 91 days. Plants exposed to Al drastically reduced flushing, indicating that Al interferes with the functioning of the shoot apex. Aluminum caused low CO2assimilation rate, largely explained by low stomatal conductance, while Al-induced decrease in photochemical performance occurred only on some dates during the experiment. In addition, the absorbed Al was mostly retained in the roots. Although counter-intuitive, as this species grows on Al-rich soils, we noted that high Al availability impairs lateral root formation, causing an impact on water uptake and gas exchange rates of this species.