ارزیابی خصوصیات جوانه‌زنی و تغییرات بیوشیمیایی دو رقم گندم (Triticum aestivum) تحت شرایط تنش سرب

Extended abstract Introduction: Heavy metals pollution is one of the most important environmental problems. This type of metals with accumulation in the food chain has a lot of human and animal hazards. Among heavy metals, lead is considered to be the most dangerous of heavy metals in the environment, which is contaminated with the environment through the lead-acid battery industry, paint additives and gasoline additives, insecticides, chemical fertilizers, car exhausters and soldering. The objective of this research was to evaluation, the effect of Pb(NO3)2 on germination characteristics and biochemical changes of two wheat cultivars (Chamran and Kohdasht cultivars). Materials and Methods: The objective of this research was to evaluation of germination and biochemical changes of two wheat cultivars under Pb(NO3)2 stress using three-parameter sigmoid model. Experimental design was factorial with complete randomized design as base design with 3 replications. The first factor was 2 wheat cultivars (Kohdasht and Chamran), and the second factor was 6 levels of Pb(NO3)2 (0, 0.25, 0.5, 0.75, 1 and 1.5 mg.L). Results: The results showed that with increasing levels of Pb(NO3)2 stress, germination percentage, germination rate, normal seedling percentage, seedling length, seedling weight and seed vigor index reduced for two wheat cultivars. Results of fitting three-parameter sigmoidal to characteristics indicated that the highest characteristics and X50 obtained from Chamran cultivar. The highest germination percentage (96%), germination rate (23 seed per day), normal seedling percentage (93.33%), seedling length (13.07 cm), seedling weight (0.07) and seedling vigor index (12.18) were attained from Chamran cultivar under non stress conditions. Pb(NO3)2 stress increased proline and catalase activity but reduced protein, proline and protein for Chamran more than Kohdasht cultivar. Conclusion: Generally, results showed that Pb(NO3)2 had a significant effect on germination characteristics and catalase, proline and protein of wheat. Finally, it can be expressed that in copper-accumulated areas, choosing proper cultivars can slightly mitigate the damages caused by copper, which in a comparison between Chamran and Kohdasht cultivars; Chamran seems more suitable in these conditions.   Highlights: Evaluation of the effect of Pb(NO3)2 stress on germination characteristics of wheat. Using of three-parameter sigmoid model for evaluation of biochemical and germination of wheat under Pb(NO3)2 stress.