Conilon and Catuaí coffee trees tolerance to toxicity caused by aluminum and manganese

Abstract

A water culture greenhouse experiment was performed to compare aluminum and manganese toxicity in «Cojea «canephora, cultivar ConilOn and Cofea arabica, cultivar Catuaí. Two seedlings of each cultivar were transplanted to ten-liter nutrient solution (NS) pots, with these characteristics: NS pH 5.5, NS pH 4.0, NS pH 4.0 + 300 mg Al/l, NS pH 4.0 + 20 mg Mn/l, NS pH 4.0 + 300 mg Al/l + 20 mg Mn/l. The experiment was performed with a 2 x 5 factorial arrange in a randomized complete block design. One plant was taken out 120 days after transplantation and, 50 days later, the second one. The tops and roots were collected separately, dried and weighed. The relation between top dry weight and roots dry weight (TIR) was calculated. There was a decrease in tops and roots growth for Conilon and Catuaí coffee trees due to aluminum toxicity. At the first harvest, Catuaí's T/R decreased in the aluminum treatments, indicating that the greatest damage was suffered by the tops. This effect was registered for Conilon's T/R only at the 170 day harvest.