Influência de herbicidas do grupo das imidazolinonas em características relacionadas a fisiologia de espécies fitorremediadoras de solo

Abstract

The objective of the study was to evaluate the influence of the commercial mixture of imazethapyr and imazapic, belonging to the imidazolinone group in characteristics related to photosynthesis of winter species. The experiment was conducted in a greenhouse in a randomized block design with four replications, arranged in 6 x 3 factorial scheme. The first factor was composed of the winter species (Brassica napus, Festuca arundinacea, Lolium multiflorum, Lotus corniculatus, Trifolium repens and Vicia sativa) and B by doses of imazethapyr and imazapic (0, 1 e 2 L ha-¹ ) applied pre-emergence where 0 represents no applied dose, recommended dose and 1 to 2 L ha-¹ twice the dose. At 60 days after emergence (DAE) Evaluations were performed in stomatal conductance of water vapor (Gs – mol m-¹ s-¹ ), transpiration rate (E - mol H2O m-² s-¹ ), leaf temperature (TlºC), internal CO2 concentration (Ci - µmol mol-¹ ), CO2 consumed (∆C - µmol mol-¹ ), photosynthetic rate (A - µmol m-² s-¹ ) and water use efficiency (EUA - mol CO2 mol H2O-¹ ). It was observed that the species B. napus and F. arundinacea regardless of the applied dose was complete plant death. The two doses of imazethapyr and imazapic negatively influenced all variables related to the physiological characteristics of the species, B. napus and F. arundinacea. The L. corniculatus and V. sativa not suffered any injury on plant physiology to apply 1 ou 2 L ha-¹ commercial mixture. It was observed that the recommended dose (1 L ha-¹) the herbicide did not cause changes in the physiological characteristics of L. multiflorum, L. corniculatus, T. repens and V. sativa. Thus it was concluded that there was no influence on physiological characteristics of the species, L. corniculatus and V. sativa when applying 1 ou 2 L ha-¹ , already L. multiflorum and T. repens there was no damage to plant physiology only when using the recommended dose of herbicide.