ALTERAÇÕES MORFOANATÔMICAS E FISIOLÓGICAS EM PLANTAS NÃO ALVO DE Bauhinia variegata L. COMO INDICADORAS DA AÇÃO DO HERBICIDA DIUROM

Abstract

The wide use of diuron herbicide in sugarcane lands has compromised surrounding uncultivated areas, which may result in acute and/or chronic damage in non-target plants, among other toxic effects in the environment. Sensitive plant species to anthropogenic stressors have been used to delimit and predict effects of toxic substances in the environment and in non-target plants, a method called environmental biomonitoring. Thus, the aim of this research was to evaluate physiological and morphoanatomic responses in Bauhinia variegata L. plants to different doses of diuron to characterize its bioindicator potential for indicating its occurrence in phytotoxic levels in the environment. Seedlings of B. variegata 90 day-old were transplanted into 10 liter pots. After acclimatization period (about 30 d) treatments consisting of diuron doses were applied: 0 (control), 400, 800, 1600 and 2400 g ai ha-1. The experiment was conducted in a randomized block design, in a 5 x 5 factorial scheme with five doses of diuron and five evaluation times and five replicates per treatment. Gas exchange, chlorophyll a fluorescence, anatomy and morphology were evaluated. The herbicide diuron changed starkly the physiological and anatomical characteristic of plants from the lowest dose applied. The effects observed, such as the visible symptoms and changes in the ETR, YII and Fv/Fm, were considered adequate biomarkers of diuron action on non-target plants. Therefore, we concluded that B. variegata is sensitive to diuron herbicide and has potential as bioindicators.