Indução de resistência em plântulas de tomate por meio do tratamento de sementes com óleos essenciais de Citrus spp

Abstract

Tomato is among the most produced and consumed vegetables in the country, having great economic importance. Pest and disease attacks cause losses and control is commonly performed with synthetic substances. Seeking the adoption of techniques of lower environmental impact assumes the induction of resistance in plants by natural products. The present work aimed to evaluate the influence of seed treatment with essential oils of Citrus spp. resistance induction of tomato seedlings. This study was carried out at the Phytopathology Laboratory of UFFS campus Laranjeiras do Sul. It used tomato seeds cv. Gaucho which were treated with 0.5% Citrus sinensis and Citrus lemon essential oil and the control with water, to both, the treatment and the control were added 0.1% Tween 20. Seedlings were collected at 5, 10, 15 20 and 25 days after sowing (DAS), we used 4 replications consisting of 8 seedlings, separated in aerial part and root. Plant material was stored at -20 ºC until biochemical analysis. Total protein content and activity of the enzymes peroxidase, polyphenoloxidase and phenylalanine ammonia lyase were determined. It was observed that the total protein content in aerial part was lower than in C. sinensis treatment at 5 to 20 DAS. For peroxidase and polyphenoloxidase, increasing activity was observed over the days, being more related to seedling development and not to essential oils. Phenylalanine ammonia-lyase showed higher activity at 25 days in the treatment with C. sinensis and C. lemon, both in aerial part and root. The results show resistance inducing effect of the essential oil of Citrus spp. in tomato seedlings by seed treatment with the essential oils, as well as the importance of complementary studies to increase the understanding of the interaction.