Cerium and samarium blocked antioxidant enzymes in wheat plants

Abstract This work was conducted to study positive and negative impacts of cerium (Ce) and samarium (Sm) on two cultivars (Arta and Baharan) in wheat plant. Symbols of stress such as proline, malondialdehyde (MDA) and antioxidant enzymes, which may be complicated in the suppression responses of plants, were also studied. Wheat plants were exposed to 0, 2500, 5000, 7500, 10,000 and 15,000 μM of Ce and Sm for 7 days. The growth enhanced in plants treated with lesser Ce and Sm concentration (2500 μM) and declined in plants treated with upper concentrations as compared to untreated plants. The treatment with 2500 μM of Ce and Sm increased dry weigh in Arta by 68.42 and 20% and in Baharan by 32.14% and 27.3%. Thus, Ce and Sm had hormesis effect on growth in wheat plants. According to plant’s growth parameter patterns, Arta cultivar had more sensitive to Sm than to Ce, whereas Baharan cultivar had sensitive to Ce than to Sm. Our results indicated impact of Ce and Sm on proline accumulation depended on the dosage of Ce and Sm. It was observed that Ce and Sm accumulated in wheat plants at higher exposure doses. Increment of MDA content by Ce and Sm treatments showed that these metals caused oxidative stress in wheat plants. Ce and Sm blocked enzymatic antioxidant system (superoxide dismutases, peroxidase and polyphenol peroxidase) in wheat. In wheat plants treated with lower Ce and Sm concentrations higher amounts of non-enzymatic antioxidant metabolites were detected. Thus, we showed the potential negative impact of unsuitable utilization of REEs in plants and suggested growth and interruption in physiological and biochemical mechanisms as a possible factor to recognize the underlying toxicological processes

<i>Bacillus subtilis</i> stimulates plant growth and production of bioactive components in saffron

The effects of B. subtilis on the morphology and physiology of saffron were investigated using two types of soils. Three different bacterial suspensions were applied at 14-day intervals to treat saffron. Morphological attributes were recorded, and the amounts of α-crocin and safranal in the stigma extracts were quantified. The longest stigma, petal, and leaf were observed in the treated groups with 105 and 108 cfu/ml. The highest weight of stigma per corm belonged to the treated groups with 102 cfu/ml in unsterile soil and 105 and 108 cfu/ml in sterile soil. Treatment with 102 and 108 cfu/ml caused a significant increase in safranal production in sterile and unsterile peat/perlite. While treatment with 105 and 108 cfu/ml in sterile peat/perlite and exposure to 102 cfu/ml in unsterile peat/perlite soil resulted in an increase in α-crocin. The data showed that B. subtlis triggers the morphological and physiological processes in saffron.</p