STRESS SIGNALLING SUBSTANCES INFLUENCE IN VEGETABLES AND THEIR ANTIOXIDANT RELATIONSHIP: A PRELIMINARY STUDY

Vegetables growing under greenhouse conditions were sprayed with salicylic acid (SA) 10^-6 M, benzoic acid (BeA) 10^-6 M and chitosan (CH) 1%, with the purpose of knowing their effects on the antioxidant levels and phenotypical parameters. Each stress signalling substance showed a different effect in each crop in both, antioxidant level and phenotypic parameters. On some cases, interaction between compounds and horticultural species was found. The plant height and root length were not affected in any of the tested vegetables. Leaf number was increased only in cabbage and the root fresh weight was increased when BeA was sprayed. This parameter was decreased in cauliflower whereas broccoli and cabbage showed no significant differences. Total fresh weight and shoot fresh weight were higher only in cabbage when sprayed with BeA. Dry weight was increased with the BeA treatment while SA and CH application caused a reduction. The total antioxidant levels were increased by SA and CH in Swiss chard and cabbage. In contrast a reduction of these substances was observed in broccoli. Cauliflower did not show any effect with the treatments used.