Photosynthesis, Salicylic Acid Content and Enzyme Activity of Triticum aestivum L. Influenced by the Use of a Seaweed Biostimulant Based on Solieria chordalis

Plant elicitation offers numerous advantages for both plant development and defense, contributing significantly to the promotion of sustainable agriculture. However, it is essential to recognize that the selection of appropriate experimental designs and techniques is crucial as they directly impact the reliability and impartiality of the data obtained. The utilization of incorrect methodologies can lead to biased and unreliable results. Therefore, an investigation was undertaken to evaluate the elicitation potential of a red seaweed biostimulant (RSB), either independently or in combination with a fungicide, under tightly controlled conditions using wheat (Triticum aestivum L.) plants. This study encompassed an assessment of various parameters at different time intervals following the application of the elicitor, including catalase, superoxide dismutase, ascorbate peroxidase, phenylalanine ammonia-lyase (PAL) activity, salicylic acid (SA) content, the incidence of powdery mildew, photosynthetic rates, and instantaneous water use efficiency. The application of the RSB demonstrated a remarkable ability to prevent the occurrence of powdery mildew in wheat plants. Conversely, the use of the fungicide, either in isolation or in combination with the RSB, led to unfavorable outcomes, manifested as negative photosynthetic rates and a decrease in the activity of certain enzymes. Importantly, it was observed that greater PAL activity did not necessarily correspond to an increased accumulation of SA within the plants.