Asghar Mosleh Arani, Alireza Amini Hajiabadi, Someye Ghasemi, Mohammad Hadi Rad,
Volume 10, Issue 45 (12-2021)
Abstract
Salinity is one of the most important abiotic stresses that reduces the growth and development of wheat. Reducing the effects of salinity with the help of plant growth-promoting rhizosphere bacteria has been considered by researchers as an environmentally friendly solution. In the present study, some physiological responses of wheat cultivar of Narin to salinity-resistant growth-promoting bacteria isolated from the rhizosphere of salt-tolerant plants) Atriplex lentiformis, Tamarix ramosissim, Seidlitzia rosmarinus, Halostachys belangeriana) were investigated. Wheat seeds after inoculation with the identified bacteria (Bacillus safensis, B. pumilus and Zhihengliuella halotolerans) were planted in pots and irrigated with saline water of 0.2 (control), 4, 8 and 16 dS/m. The results showed all isolated bacteria had the ability to produce auxin, siderophore, hydrogen cyanide, 1-aminocyclopropane-1-carboxylic acid deaminase (ACC deaminase) and phosphate solubility.With increasing salinity, chlorophyll content decreased in all treatments compared to the control. The use of bacteria increased 21 to 92.6 to 175 and 21 to 52% of chlorophyll a, b and total chlorophyll content among salinity treatments, respectively. Increased salinity raissed content of proline (136-136%), total phenol (11-92.5%), free radical scavenging capacity (12.5-89%) and total soluble sugars (7.5-1.5%) in salinity treatments inoculated with bacteria compared to the control. The growth-promoting bacteria in this study improved wheat resistance to salinity stress. Improving the physiological conditions of plant under the positive effect of bacteria eventually increased the plant biomass, in which the role of B. safensis was more than the other two bacteria. The results of this study showed that the plant growth-promoting bacteria of halophytic rangeland plants can play a role in improving the growth indices of wheat plants in saline conditions.
Sara Salimian Rizi, Zahra Rezayatmand, Monireh Ranjbar, Nasrin Yazdanpanahi, Zarrindokht Emami Karvani,
Volume 13, Issue 64 (1-2025)
Abstract
Artemisia absinthium (L.) is known as wormwood and grand wormwood. The use of growth-promoting bacteria reduces environmental stress and improves plant growth. Some Bacillus spp. found in the rhizosphere of plants, which can produce auxin hormone and have phosphate dissolution ability, which improves plant growth. This study aimed to isolate Bacillus spp. from the rhizosphere of A. absinthium L. and to evaluate the ability of the isolated strains for auxin production and phosphate dissolution as well as their effect on biochemical indices of A. absinthium L. under salinity stress. Soil samples were collected from the rhizosphere of A. absinthium L. and Bacillus spp. were isolated and purified from them, utilizing an initial heat shock for bacterial spore selection and then cultivation of spores on nutrient agar. In the next step, quantitative measurements of auxin production capacity and inorganic phosphate dissolution were performed on the purified isolates, and then the selected isolates that had more auxin production and phosphate dissolution were biochemically and molecularly identified. Finally, the effect of selected bacteria on some biochemical characteristics of the A. absinthium plant under salt stress was investigated. The effect of four levels of inoculation (no inoculation, inoculation with B. cereus B strain, B. cereus E strain, and co-inoculation with B. cereus B strain and B. cereus E strain) was investigated on the biochemical indices of A. absinthium under three levels of salinity stress (control, 75 mM, and 150 mM). The production of malondialdehyde (MDA), protein, proline, superoxide dismutase enzyme (SOD), catalase (CAT), peroxidase (POX), and total phenol increased with increasing salinity. The results showed that the inoculation of Bacillus bacteria under salinity stress decreased proline and MDA and increased the amount of protein, total phenol and antioxidant enzymes (superoxide dismutase, catalase, and peroxidase). The best results were obtained by the combined inoculation of rhizosphere bacteria, B. cereus B and E strains, under salinity stress (75 mM NaCl), in which the greatest decrease in proline (90%) and MDA (90%) as well as the greatest increase in protein (9%), total phenol (180%), and antioxidant enzymes including superoxide dismutase (SOD) (50%), catalase (CAT) (40%), and peroxidase (POX) (70%) was obtained compared to the control.
