توصيفگر ها :
تنش خشكي , علفكش , گياه دارويي , عملكرد دانه , اجزاي شيميايي روغن , لينولئيك اسيد , تنش اكسيداتيو
چكيده انگليسي :
Black cumin (Nigella sativa) is a medicinal and aromatic plant species, however, its quality and quantity may be effected by drought and herbicide stresses. Therefore, measuring of its physiological, biochemical and morphological traits under different irrigation regimes and some herbicide treatments could provide valuable information for successful selection and breeding of tolerant genotypes. In this research we conducted three experimenrs. In the first experiment, physiological, morphological and biochemical traits of ten black cumin genotypes (‘Arak’, ‘Isfahan’, ‘Semirom’, ‘Shahreza’, ‘ShahrKord’, ‘Mashhad’, ‘Afghanistan’, ‘Pakistan’, ‘India’, and ‘Syria’) under three irrigation regimes (40% (I1), 60% (I2) and 80% (I3) of permissible moisture discharge) were investigated during 2017-2018 using a factorial arrangement based on a randomized complete block design with three replicates. The second experiment was performed as factorial, based on the randomized complete block design using three herbicides (acetochlor, butisan star and treflan) with three rates (0.75X, 1X and 1.25X that X equals to the recommended rate). Herbicides were applied at pre and post emergent stages using a pot experiment with three replications. The third experiment was arrange in factorial based in a randomized complete block design with three replications in a pot. The treatments were two irrigation levels (control and moderate stress), three rates of acetochlor herbicide (control, 1X and 1.25X that X equals to the recommended rate) and four black cumin genotypes (‘Arak’, ‘ShahrKord’, ‘Mashhad’and ‘Afghanistan’). Water stress upgraded carotenoids, proline, total soluble carbohydrates, essential oil, MDA and H2O2 contents and CAT and APX activities but downgraded RWC, chlorophyll content, seed yield and yield components. Highest increases in carotenoid, TSC, proline, and essential oil contents and CAT and APX activities were noted in Shahreza, Shahrekord, Arak, Shahrekord, Semirom and Mashhad under I3, respectively. Whereas the lowest decreases in chlorophyll, H2O2, yield and RWC in Semirom and MDA in Isfahan were marked under I3. Mashhad under I1, Arak under I2 and Semirom under I3 produced the highest yield while Shahrekord contained the highest essential oil content under all irrigation regimes. The results showed that physiological, biochemical and morphological traits of black cumin were affected by irrigation regimes, however, the effects were depend on genotype, irrigation regime and the trait. Therefore, selection of more tolerant genotypes may be possible for direct use or breeding programmes. Based on stress susceptibility index, Shahre -Kord under I2 and Semiron under I3 were the most tolerant genotypes. Linoleic (46.43%), oleic (24.40%), and palmitic (15.04%) acids were found to be the main fatty acids produced by the species. Overall, results indicated that black cumin genotypes were both qualitatively and quantitatively affected by drought level; hence, proper irrigation regimes might be used to optimise fatty acid compositions in the selected genotypes. The results also indicated that as hebicides concentrations increased MDA, H2O2, antioxidant enzymes activties increased and RWC, chlorophyll, carotenoid, plant height, branches number, seed yield and components of the yield decreased. In simultaneous application of drought, genotype and herbicide led to physiological and morphology alterations that drought stress and increasing dose of herbicide acetochlor reduced plant height, shoot dry weight and seed yield. Highest and lowest sensitively to herbicide acetochlor in all rate herbicide was detected in Mashhad and Shahrkord under low rate herbicide acetochlor respectively. Finally it can be concluded that drought stress reduced 15% harmful effects high rate herbicide acetochlor on black cumin.