Plant Stress
Farhad Azarmi-Atajan; Mohammad Hassan Sayyari-Zohan
Abstract
Purpose: The effect of Pseudomonas sp. rhizobacteria as plant growth-promoting rhizobacteria (PGPR) in alleviating salt stress in the lettuce plant was studied under greenhouse condition. Research Method: The experiment was conducted following a completely randomized design with three replicates. The ...
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Purpose: The effect of Pseudomonas sp. rhizobacteria as plant growth-promoting rhizobacteria (PGPR) in alleviating salt stress in the lettuce plant was studied under greenhouse condition. Research Method: The experiment was conducted following a completely randomized design with three replicates. The treatments include four Pseudomonas sp. strains (B0 (non-inoculated), B1, B2 and B3) as PGPR and three levels of irrigation water salinity (0, 4 and 8 dS m-1 as NaCl). Findings: The results showed that with rising salinity levels the lettuce fresh and dry weight, chlorophyll and carotenoids content and K concentration decreased but, the content of membrane stability index (MSI), Na and Na/K ratio increased. However, inoculation of the lettuce plants by PGPR significantly increased the lettuce fresh and dry weight, chlorophyll and carotenoids content, K concentration and K/Na ratio under various salinity levels. Among the PGPR strain, the B2 strain was more effective in the improvement of the lettuce resistance to salinity stress. Research limitations: If antioxidant compounds and enzymes were measured in this study, it would be helpful to interpret the results. Originality/Value: with regards to the useful impact of the PGPR on the lettuce plant under soil salinity, these microorganisms can be used as biofertilizer to provide nutrients and increase plant resistance to salt stress.
Plant Stress
Farid Moradinezhad; Soheyla Hajizadegan; Mohammad Hassan Sayyari; Mehdi Khayyat
Abstract
Purpose: Boron toxicity is an important factor, which reduces crop productivity, quality and medicinal characteristics around the world. Research method: This research was conducted to investigate the effect of different boron (B) concentrations on growth, chemical and physiological characteristics of ...
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Purpose: Boron toxicity is an important factor, which reduces crop productivity, quality and medicinal characteristics around the world. Research method: This research was conducted to investigate the effect of different boron (B) concentrations on growth, chemical and physiological characteristics of Satureja hortensis plants under greenhouse conditions in 2016. The experiment was conducted in a glasshouse with 25±3 °C and 15±3 °C (day-night) temperatures, 60% relative humidity and 340 ppm CO2 concentration. Treatments were different B concentrations as H3BO3 that used via irrigation water including 0, 5, 10, 25 and 50 mg L–1. Main findings: Results indicated that total nitrogen, Fm, Fv, Fv/Fm, chlorophyll a, b and total, leaf number, relative water content (RWC), specific leaf weight (SLW), areal fresh and dry weights significantly decreased by B increase. On the other hand, increased B concentration in leaf was led to increasing of F0, ΦN0, proline, total carbohydrate and phenolics, specific leaf area and leaf electrolyte leakage. Limitations: No significant limitation to report. Originality/Value: It is concluded that summer savory can tolerate B concentrations up to 10 mg L–1, and leaf boron accumulation significantly inhibited, however, increased with more B concentration of root medium, which affected all physiological aspects mentioned above.
