Volume 14, Issue 1 (3-2023)                   2023, 14(1): 89-107 | Back to browse issues page


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Department of Environmental Sciences, Faculty of Natural Resources and Desert Studies, Yazd University, Yazd, Iran.
Abstract:   (700 Views)
Abstract
In this research, the effect of plant growth-promoting rhizobacteria, Bacillus pumilus, and Zhihengliuella halotolerans, on the morpho-physiological traits of Nitraria schoberi under the influence of dust (control and 1.5 g/m2/month) was investigated. The results showed that dust had a negative effect on the morphological and physiological traits of the plant. Dust caused a decrease of 20, 15, 17 and 20% in chlorophyll a, carotenoid, total soluble protein, and total dry biomass and an increase in the total flavonoids, total phenol content, total antioxidant capacity and glycine betaine amounting to 107, 32, 15 and 10 percents, respectively. Both bacteria improved the condition of the plant against stress, so that B. pumilus and Z. halotolerans increased the amount of chlorophyll b by 13 and 21%, protein by 27 and 43%, and total biomass by 60 and 27%, respectively. In this experiment, the role of B. pumilus strain was more than that of Z. halotolerans strain, so that B. pumilus strain alone had the greatest effect in increasing chlorophyll a and seedling quality index by 52 and 108%, respectively. The results showed that B. pumilus and Z. halotolerans strains can increase the resistance of the Nitraria schoberi to dust stress and help us to stabilize salty dusts in playas.

Background and Objective: Salt and dust can cause harmful effects on the photosynthetic activity and serious damage to the plant. Plants under these stresses will experience a series of morphological, physiological and biochemical changes (4). In recent years, the use of plant growth-promoting rhizobacteria as a leading strategy in reducing the effects of environmental stresses has attracted the attention of researchers (3). In this research, the effect of inoculation of two bacteria, Bacillus pumilus and Zhihengliuella halotolerans, on some morphological and physiological traits of Nitraria schoberi under dust stress was investigated. The results of this research can help us in the optimal afforestation of this species under dust in the conditions of climate change in arid and semi-arid ecosystems.

Methods: Three-month old seedlings of the same size were inoculated by plant growth-promoting bacteria under dust stress in a two-factor factorial experiment with a randomized complete block design in three replications in a period of 5 months. The strains of Bacillus pumilus and Zhihengliuella halotolerans were provided by previously purified research by Amini et al. (2022) (1). Inoculation was applied twice to the plant roots. Only nutrient broth solution without bacteria was applied to the control plants. Dusting was done using a simulator. The amount of falling dust equal to 1.5 grams per square meter per month was applied once a week. After completing the treatments, 8-month old seedlings were sampled for physiological and morphological tests. The amounts of chlorophyll a, b and leaf carotenoid, total anthocyanin and flavonoid, total phenol content, total antioxidant activity, glycine betaine, malondialdehyde and total soluble protein were measured (2).

Results: The results showed that dust had a negative effect on the morphological and physiological traits of the plant. Dust caused a decrease of 20, 15, 17 and 20% in chlorophyll a, carotenoid, total soluble protein, and total dry biomass and an increase in total flavonoid, total phenol content, total antioxidant capacity and glycine betaine amounting to 107, 32, 15 and 10 percents, respectively. Both bacteria improved the condition of the plant against stress, so that B. pumilus and Z. halotolerans increased the amount of chlorophyll b by 13 and 21%, protein by 27 and 43%, and total biomass by 60 and 27%, respectively. In this experiment, the role of B. pumilus strain was more pronounced than that of Z. halotolerans strain. B. pumilus strain alone had the greatest effect in increasing chlorophyll a and seedling quality index by 52 and 108%, respectively. The results showed that the plant growth-promoting rhizobacteria could increase the resistance of the Nitraria schoberi under dust stress and help us to stabilize salty dusts in playas.

Conclusions: The results showed that the plant growth-promoting bacteria improved the morphological and physiological traits of Nitraria schoberi seedlings under dust stress compared to the control. It can be concluded that the rhizosphere of salt-tolerant plants are suitable sources for isolating salt-resistant bacteria. It is also concluded that B. pumilus and Z. halotolerans can increase resistance to dust stress via improving Nitraria schoberi seedlings physiological traits. However, it is necessary to conduct additional field research in the desert habitat to examine the performance and efficiency of these bacterial strains as suitable bio-fertilizers to deal with dusty conditions.

References:
1. Amini Hajiabadi, A., Mosleh Arani, A., Ghasemi, S., Rad, M.H., Etesami, H., Shabazi Manshadi, S., Dolati, A., 2021. Mining the rhizosphere of halophytic rangeland plants for halotolerant bacteria to improve growth and yield of salinity-stressed wheat. Plant Physiology and Biochemistry 163: 139153.
2. Dickson, A., Leaf, A.L., Hosner, J.F., 1960. Quality appraisal of white spruce and white pine seedling stock in nurseries. The Forestry Chronicle 36(1): 1013.
3. Rastegari, A.A., Yadav, A.N., Yadav, N., 2020. New and Future Developments in Microbial Biotechnology and Bioengineering: Trends of Microbial Biotechnology for Sustainable Agriculture and Biomedicine Systems: Diversity and Functional Perspectives. Elsevier: Amsterdam, The Netherlands.
4. Zilaie, M.N., Arani, A.M., Etesami, H., Dinarvand, M., Dolati, A., 2022. Halotolerant plant growth-promoting rhizobacteria-mediated alleviation of salinity and dust stress and improvement of forage yield in the desert halophyte Seidlitzia rosmarinus. Environmental and Experimental Botany 201: 104952.
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Type of Study: Research | Subject: Plant water relations
Received: 2023/01/30 | Accepted: 2023/03/30 | Published: 2023/06/18

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