Abstract: (19 Views)
Almond (Prunus dulcis) is a commercially important stone fruit tree in Iran, particularly in Chaharmahal and Bakhtiari province. Bacterial canker caused by the pathogen Pseudomonas syringae pv. Syringae is a significant disease in almond orchards in this region. Copper-based compounds, such as copper oxychloride, are commonly used for disease control; however, these compounds may cause phytotoxicity and pose environmental risks at high concentrations. Therefore, alternative compounds such as potassium silicate, which can stimulate the plant defense system against bacterial canker, were evaluated.
In the laboratory, the effects of potassium silicate and copper oxychloride, applied separately in Petri dishes, on the growth of the pathogenic bacterium were investigated. The concentrations used for both compounds were 500, 1000, and 1500 mg/L. After 48 hours of treatment application into the wells, the inhibition zone around each well was measured, and the percentage of inhibitory control for each concentration was calculated compared to the control. The results showed that the highest inhibitory effect among potassium silicate treatments was observed at 1500 mg/L, with 58.64% control, which was statistically lower than all three concentrations of copper oxychloride. The inhibitory percentages for copper oxychloride at 500, 1000, and 1500 mg/L were 66.42%, 74.32%, and 78.22%, respectively.
Under greenhouse conditions, potassium silicate at 1500 mg/L resulted in a 65.12% reduction in leaf spot severity. In the evaluation of fruit morphological traits, the best performance was observed in the potassium silicate 1500 mg/L treatment, which showed a significant difference compared with copper oxychloride.
Regarding gene expression, the highest expression of the phenylalanine ammonia-lyase (PAL) gene was observed in the copper oxychloride treatment (8.3-fold relative to the control on day 20). However, the potassium silicate 1500 mg/L treatment also significantly increased PAL gene expression up to 2.6-fold relative to the control and was statistically higher than the copper oxychloride 500 mg/L treatment.
For the peroxidase gene, potassium silicate treatment on day 20 increased gene expression by 15.5-fold relative to the control, which was comparable to the copper oxychloride treatment. This result indicates the strong ability of potassium silicate to induce the plant’s enzymatic defense system.
Overall, this study demonstrated that nutritional compounds such as potassium silicate, which possess antibacterial properties and contribute to plant and fruit quality, can be considered as alternatives to copper oxychloride. In contrast, copper-based compounds may cause phytotoxicity at high concentrations, reduce soil microbial populations, and pose environmental risks.
In the laboratory, the effects of potassium silicate and copper oxychloride, applied separately in Petri dishes, on the growth of the pathogenic bacterium were investigated. The concentrations used for both compounds were 500, 1000, and 1500 mg/L. After 48 hours of treatment application into the wells, the inhibition zone around each well was measured, and the percentage of inhibitory control for each concentration was calculated compared to the control. The results showed that the highest inhibitory effect among potassium silicate treatments was observed at 1500 mg/L, with 58.64% control, which was statistically lower than all three concentrations of copper oxychloride. The inhibitory percentages for copper oxychloride at 500, 1000, and 1500 mg/L were 66.42%, 74.32%, and 78.22%, respectively.
Under greenhouse conditions, potassium silicate at 1500 mg/L resulted in a 65.12% reduction in leaf spot severity. In the evaluation of fruit morphological traits, the best performance was observed in the potassium silicate 1500 mg/L treatment, which showed a significant difference compared with copper oxychloride.
Regarding gene expression, the highest expression of the phenylalanine ammonia-lyase (PAL) gene was observed in the copper oxychloride treatment (8.3-fold relative to the control on day 20). However, the potassium silicate 1500 mg/L treatment also significantly increased PAL gene expression up to 2.6-fold relative to the control and was statistically higher than the copper oxychloride 500 mg/L treatment.
For the peroxidase gene, potassium silicate treatment on day 20 increased gene expression by 15.5-fold relative to the control, which was comparable to the copper oxychloride treatment. This result indicates the strong ability of potassium silicate to induce the plant’s enzymatic defense system.
Overall, this study demonstrated that nutritional compounds such as potassium silicate, which possess antibacterial properties and contribute to plant and fruit quality, can be considered as alternatives to copper oxychloride. In contrast, copper-based compounds may cause phytotoxicity at high concentrations, reduce soil microbial populations, and pose environmental risks.
Article number: 5
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