Leandro Henrique de Souza Mota
◽
Silvana de Paula Quintão Scalon
◽
Daiane Mugnol Dresch
◽
Lourenço Quintão Scalon
◽
César José da Silva
The aluminium at toxic levels causes biochemical and physiological damage that inhibits plant growth and limits productivity. Root growth, chlorophyll a fluorescence, and enzyme activity of four accessions of Jatropha curcas were evaluated under cultivation conditions with different levels of aluminium. The experimental design was completely randomized with a split-split-plot design, in which the plots included four levels of aluminium in the soil (0.0, 8.2, 16.5, and 24.0 mmolc dm-3), the split-plot were the four accessions of J. curcas seeds (P1 = Dourados, MS; P2 = Montes Claros, MG; P3 = Alta Floresta, MT; P4 = Petrolina, PE), and split-split-plot in all four times of evaluation (25, 50, 75, and 100 days after emergence - DAE) with four replications. At 100 DAE were evaluated the curve of transient chlorophyll a fluorescence (OJIP) and enzyme activity, the treatments were arranged in split-plot, being four levels of aluminium in the soil and the four accesses of J. curcas. Six readings for the OJIP curve and three repetitions for enzymatic analysis were conducted. The characteristics of gas exchange and chlorophyll a fluorescence indicated that doses above 8.2 accentuated aluminium stress on plants from all accessions. The reduced efficiency of carboxylation of Rubisco and the results of the OJIP test indicated that photochemical efficiency of all varieties was decreased. The activity of the enzymes catalase, peroxidase, and superoxide dismutase was higher in the presence of aluminium for the accessions P3-Alta Floresta and P4-Petrolina. Our results indicate the greater tolerance of these accesses to aluminium stress conditions.
Gas exchange and antioxidant activity accessions of Jatropha curcas L. under aluminium (Al) stress