Avaliação da germinação e do crescimento inicial de plântulas de Lactuca sativa L. expostas ao cloreto de alumínio em microambiente

Abstract

Aluminum when in low soil concentrations can promote growth or even other benefits to plants. However, in acidic soils (pH <5) this metal can cause phytotoxic effects on plants, becoming one of the limiting factors for their growth. The present study aimed to evaluate the phytotoxicity of aluminum chloride (AlCl3) on the germination and initial development of Lactuca sativa L. For this purpose, aqueous solutions of AlCl3 were prepared at concentrations of 0 mg.L-1, 5 mg.L-1,10 mg.L-1, 50 mg.L-1 and 100 mg.L-1. Followed by the application of 3 mL of each solution in Petri dishes containing 25 lettuce seeds each, germinated in a B.O.D (Biochemical Oxigen Demand) chamber lasting seven days. The parameters used to evaluate Al phytotoxicity were: root length, hypocotyl and total, root diameter, NSG / day, IVG, vigor, IT chlorophyll and carotenoid contents and physicochemical parameters. Considering the phytotoxic effects of aluminum demonstrated by the reduction in root size, hypocotyl, total length and increase of root diameter of the seedlings that received the aluminum treatments, the seedlings that received the treatment with the highest concentration showed to be less tolerant to aluminum, however germination, IVG, vigor and chlorophyll and carotenoid contents were not negatively affected by aluminum. Thus it can be concluded that aluminum, despite causing root damage, was not sufficient to inhibit the initial development of lettuce seedlings.