Effect of Nano Sio2 on Physiological Features of Pistacia atlantica subsp. mutica under Drought Stress

It is a strategic need to find drought-resistant tree species with the aim of reviving Zagros forests. There are no enough researches about the effect of nano particls on the woody plants especially on their physiological features, while most of recordes have focused on crops. Therefore, in the current research, we investigated the effect of Nano Sio2 on Wild Pistachio (Pistacia atlantica subsp. mutica) seedlings in order to finding a resistant plant for rehabilitation of Zagros forest.

The experiment was based on a completely randomized design with 126 seedlings, six treatments of Nano Sio2 (control, 100, 300, 700, 1500, and 3000 mg. l-1) for 30 days and three replicates at three levels of drought stresses (control, every other day of irrigation; moderate, every four days of irrigation; and severe drought, with no irrigation). At the end, the physiological characteristics such as chlorophyll a, b, total, caratoneid, carbohydrate, proline content, enzyme peroxidase of guaiacol and catalase were analysed in treated leaves seedlings.

The results showed that levels of drought stress decreased the chlorophyll, caratoneid contents and increased the soluble carbohydrates, proline, and antioxidant enzymes. In the other words, the seedlings reacted differently to nano Sio2 treatments that the highest amount of carbohydrates and catalase were observed in 700 mg.l-1; chlorophyll a, b, total and caratoneid in 3000 mg.l-1, and proline and peroxidase in 300 mg.l-1. Furthermore, the different levels of drought stresses made a reduction in the types of chlorophylls and caratoneid; increase in carbohydrates, proline, and antioxidant enzymes.

It can be concluded that the most physiological traits were increased under drought stress and the Sio2 nanoparticles mitigated some traits like types of chlorophyll and carotenoids. Concentrations of 300, 700 and 3000 mg. l-1 had a better effect on many of the physiological traits than the others. Reducing the types of chlorophyll and carotenoids and increasing carbohydrate, proline and antioxidant enzymes are occurred in plants to tolerate the drought stress. Due to the lack of basic information about the resistant mechanism in the endemic tree species from Zagros forest in response to nanoparticles, this study will be a great assistance to develop nano technology in wooden plants. It is suggested to study the effect of Sio2 nano particles for longer periods or on some more species that could be a considerable way to find reliable results. These results may lead into economical production of drought resistant seedlings in large scales. Keywords: Drought resistant; leaf physiological features; Sio2 Nano-particles; Chlorophyll; Pistachio.