EFFECT OF SILICON ON THE ACTIVITY OF ANTIOXIDANT ENZYMES AND THE PHOTOSYNTHETIC RATE OF CUCUMBER UNDER MITE INFESTATION

The aim of the study was to evaluate the effect of silicon on the activity of antioxidant enzymes and the photo,synthetic rate of cucumber plants (Cucumis sativas L.) cv. Get gana under mite infestation. Four variants consisting of I control, 2 mite-infested plants, 3 silicon-treated plants, and 4 mite-infested plants, treated with silicon, were analyed. Plants were grown hydroponically and silicon (Si) was applied to the nutrient solution in form of Na2SiO3. The plants have been infested by the two-spotted spider mite Tetranychus urticae and 20 days later - analyzed The results show a decrease in the mite population in the Si treated plants. The activities of guaiacol peroxidase (GPOD) and,syringaldazine peroxiduse (SPOD) in the leaves of the mite infested plants increased by 175% and 197% respectively, and the net photosynthetic rate (P-N) in the mite-infested plants was reduced by 51%, compared to the control. It was established that Si supply to a nutrient solution of the mite-infested plants decreases the activities of GPOD and SPOD by 62% and 57 respectively and enhances the net photosynthetic rate by 84%.