EFFECT OF GLUCOSE AND LACTOSE ON UPTAKE OF PHENOL BY LEMNA MINOR

Previous researches have demonstrated that presence of some carbohydrates in the culture medium will cause callus induction and frond regeneration in Lemna minor, and it is expected that presence of carbohydrates will affect the uptake of organics by this plant. However, limited studies have investigated the uptake of organics by this plant. The aim of this study was to clarify the effect of conventional carbohydrates such as glucose and lactose on uptake of phenol by Lemna- minor. Experiments were carried out in the presence and absence of glucose and lactose in the growth solution. The growth solution was fresh water collected from river and phenol was added to it. The initial concentrations of phenol were 20, 50 and 100 mg/L and density of Lemna minor (fresh weight) were 50, 100 and 150 g/m2. The plants were contacted with growth solutions for 4 weeks. Control bottles (without plants) were examined with the same manner. The bottles were placed under white cool light with 12h photo periods at room temperature. Every four days sample was taken and the concentration of phenol was determined by spectrophotometer. Uptake of phenol by lemna-minor increased with increasing the contact time and decreased by increasing phenol concentration. In the presence of glucose and lactose in the growth solutions, uptake of phenol was decreased. Phenol uptake was dependent to plant density and when Lemna minor completely covered the surface of the water, uptake decreased.
In the presence of glucose and lactose, uptake of phenol by Lemna minor was decreased. Uptake of phenol by lemna minor was affected by density of plant.