In recent decades, the impacts of climate change an‎d rising temperatures on plant function have become distinctly evident. High temperatures not only constrain the cultivation of plants but also reduce the quality an‎d yield of cool-season crops such as cabbage. Greenhouse cultivation has provided a way to extend the production period an‎d better manage environmental conditions. Yet, in practice, frequent power outages often lead to sudden rises in greenhouse temperature, exposing plants to heat stress. This challenge highlights the importance of developing practical strategies to strengthen the tolerance of cabbage to high-temperature stress. This study examined the effects of different silicon sources on the physiological performance of white an‎d red cabbage under high-temperature stress conditions. The experiment was conducted in the educational greenhouse of Isfahan University of Technology using a completely ran‎domized factorial design with three replications. Experimental treatments included various silicon sources (control, nanosilicon, biosilicon, an‎d silicon dioxide at concentrations of 1 an‎d 2 millimolar) an‎d three temperature levels (greenhouse temperature 25 ± 1°C, 30 ± 1°C, an‎d 35 ± 1°C. Results showed that elevated temperatures reduced plant height, fresh an‎d dry weight, chlorophyll content, stomatal width, an‎d phenols, while increasing electrolyte leakage, proline, flavonoids, an‎d antioxidant activity. Application of silicon, particularly silicon dioxide, significantly improved relative water content an‎d dry weight while mitigating the negative effects of heat stress. In red cabbage as superior varieties, silicon application resulted in decreased catalase enzyme activity, whereas foliar application of 1 mM biosilicon enhanced ascorbate peroxidase activity. Furthermore, high-performance liquid chromatography (HPLC) data demonstrated increases in several glucosinolate compounds (sinigrin, glucoraphanin, gluconapin, an‎d glucobrassicin), flavonoids (catechin, lutein, rutin, quercetin, an‎d kaempferol), an‎d phenolic compounds (gallic acid) at elevated temperatures under silicon treatments.

مريم حقيقي , مهدي رحيم ملك

حميد زيلوئي

علي نيكبخت , محمدحسين اهتمام