Tolerância de espécies nativas do cerrado ao alumínio em solução

Abstract

The Cerrado biome (Brazilian savanna) occupies about 30% of the Brazilian territory. Its soils have limitations for the development of crops of economic interest, as they are naturally acidic, with high levels of aluminum (Al) and low availability of nutrients. However, native plant species tend to be insensitive to excess Al in the soil, using mechanisms of exclusion or internal detoxification. The fundamental objective of this study was to study the tolerance of seedlings of five native vegetal from to the Cerrado to increasing doses of Al (0, 10, 30, 60, and 120 mg L-1) in nutrient solution. The experiment was conducted in a greenhouse, in a randomized block design, with a 5 x 5 factorial scheme and three replicates. The following native species were used: Aegiphila sellowiana (Pau-tamanco), Tabernaemontana hystrix (Leiteiro), Lafoensia pacari (Dedaleiro), Cordia ecalyculata (Café-de-bugre), and Cedrela fissilis (Cedro-Rosa). The seedlings were transplanted into Leonard pots containing nutrient solution and different concentrations of Al. After 21 days, results of shoot and root biomass were submitted to analysis of variance and compared by Tukey's test, at the 5% level of significance. There was no significant difference for the biomass of the shoots and roots of the species studied with the increase in the concentration of Al in solution, probably due to the period of contact between the seedlings and the Al in solution being insufficient for the appearance of the Al effects. However, the fact that plant development was not affected was interpreted as indicative of tolerance to this type of abiotic stress, which normally is not observed in cultivated plants. Leonard vessels were considered suitable experimental apparatus for studying the influence of Al in solution on plant development. It was concluded that the five native species were tolerant to abiotic stress caused by exposure to nutrient solutions containing up to 120 mg L-1 of Al.