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O arsênio é o elemento químico nocivo à saúde humana. A recuperação de áreas com presença de As requer utilização de espécies tolerantes e manejo adequado da adubação, especialmente do fósforo (P). Assim, o objetivo deste trabalho foi avaliar a interação de doses As e P no desenvolvimento de mudas florestais ingá e angico-vermelho. O delineamento foi em blocos casualizados, em esquema fatorial 5 x 3, sendo 5 doses de As (0, 100, 200, 400 e 800 mg dm-3) e 3 doses de P (0, 150 e 450 mg dm-3) com três repetições. As variáveis analisadas foram matéria seca, altura e diâmetro das plantas e análise do néctar produzido pelas plantas. Aos 10 dias de cultivo as plantas de ingá apresentaram intoxicação com clorose internerval, seguida de necrose, nas doses de 400 e 800 mg dm-3 de As e na ausência de P. Por outro lado, as doses crescentes de arsênio, mesmo na presença do P, contribuíram para reduzir a produção de matéria seca de raízes e parte aérea, altura e diâmetro de planta. As plantas de angico apresentaram-se mais tolerantes que as de ingá. Na avaliação do néctar coletado constatou-se que tais espécies podem absorver, transportar e eliminar arsênio por meio dos nectários foliares. Maiores teores de As no néctar foram encontrados em angico-vermelho (40,50 mg kg-1), enquanto o ingá apresentou teor médio de 3,24 mg kg-1, para a combinação 100 mg dm-3 de As e ausência de P, ambos valores acima do permitido em mel para consumo humano. A B S T R A C T Arsenic (As) is the chemical element most harmful to human health. Rehabilitation of areas with As presence requires the use of tolerant species and adequate fertilization management, especially phosphorus (P). Therefore, this work aims to evaluate the As and P interaction in the seedlings development of species inga (Inga edulis Mart.) and angico-vermelho [Anadenanthera peregrina (L.) Speg.]. The experimental design was a randomized complete block, with three replications, in a 5 x 3 factorial scheme. We used 5 doses of As (0, 100, 200, 400 and 800 mg dm-3) and 3 doses of P (0, 150 and 450 mg dm-3). The analyzed variables were dry matter, height and diameter of the plants and nectar produced by plants. At 10 cultivation days, the ingá plants presented the basal leaves margins purplish with internerval chlorosis, followed by necrosis, only at 400 and 800 mg dm-3 of As and in the P absence. This shows P reduces As toxicity to plants, even at high doses. On the other hand, increasing arsenic doses, even in the P presence, contributed to significantly decrease of roots and shoot dry matter production, height and plant diameter. Increasing P doses for each As dose resulted in increased growth variables, especially in angico plants. The As toxic effect varies according to species, taking into account the symptoms of leaf toxicity and the growth variables analyzed. The angico plants were more tolerant than inga. Booth forest species can absorb, transport and eliminate part of the arsenic through the foliar nectaries, probably, as an elimination mechanism of this metalloid. Higher As-levels in nectar were found in angico (40.50 mg kg-1), while the ingá presented mean content of 3.24 mg kg-1, for the combination of 100 mg dm-3 of As and P absence, both values above that allowed in honey for human consumption. Keywords: phytoremediation, arsenate, toxicity, inga, angico |
