ISSN: 2474-8846
Authors: Kiani H* and Sohrabi Y
The production of active oxygen species increases under drought stress conditions, which means that their removal or deactivation is out of plant power. Therefore, most plants in the face of drought stress require solutions adopted by farm managers. In order to investigate the effect of various irrigation regimes and anti-evapotranspiration effect of different concentrations of tragacanth gum on protective mechanisms of Nigella sativa L., a factorial experiment was conducted in a completely randomized design with three replications in the greenhouse of the Faculty of Agriculture, the University of Kurdistan in 2018. The experimental factors included irrigation at three levels of 100 (full irrigation), 70 (mild drought stress), and 40% (severe drought stress) of field capacity of soil and spraying with tragacanth gum at six concentrations of 0, 1.25, 2.5, 5, 7.5, and 10 g/L. The results showed that increasing the intensity of drought stress (irrigation reduction) resulted in increased levels of H2O2, MDA, SOD, POD, proline, soluble carbohydrates (water and alcohol soluble), and osmotic potential of the plant and reduced grain yield. The effect of different concentrations of tragacanth gum was differed at different levels of irrigation. In full irrigation, the concentration of 1.25 g/L was positive for all studied traits. In mild drought stress, the use of higher concentrations of tragacanth (up to 5 g/L) had the best efficiency, and concentrations greater than 5 g/L had opposite effects on the traits. In severe drought stress, the use of higher concentrations of tragacanth was beneficial and concentrations up to 7.5 g/L improved the studied traits, but concentrations of 10 g/L had a negative effect on these traits. Regarding that the application of appropriate concentrations of tragacanth gum improved the measured traits and increase grain yield under mild and severe drought stress by 11.6% and 28.2%, respectively, it may be introduced as a novel anti-evapotranspiration agent with natural origin and may be useful in areas with drought stress.
Keywords: Antioxidant Enzymes; Compatible Osmolytes; Oxidative Stress; Tragacanth; Water Deficiency
