Amir Hossein Shahbazi; Seyyed Javad Mousavizadeh; Kambiz Mashayekhi; Ayoub Ghorbani Dehkordi
Abstract
Introduction Cucumber is one of the most widely cultivated greenhouse vegetables in Iran. It is essential to properly nourish plants and use elements and compounds that increase yield ...
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Introduction Cucumber is one of the most widely cultivated greenhouse vegetables in Iran. It is essential to properly nourish plants and use elements and compounds that increase yield while maintaining and improving quality. However, its production is often challenged by environmental stresses that reduce water and nutrient uptake, directly affecting yield and quality. Salicylic acid serves as a key plant regulator and stress mitigator, while boron plays a critical role in sugar transport, hormone regulation, and fruit and leaf formation. This study aimed to evaluate the combined effect of salicylic acid and boric acid on the growth and yield of greenhouse cucumber (Cucumis sativus cv. Gohar) under soil-based cultivation. Materials and MethodsThe experiment was conducted using a factorial arrangement based on a randomized complete block design (RCBD) with three replications. Treatments included foliar spraying of salicylic acid at three concentrations (0, 0.5 and 1 mM) and boric acid at three concentrations (0, 2 and 4 mM). Foliar applications were carried out four times at 10-day intervals, starting from the emergence of the second true leaf. Morphological traits such as plant height, number of leaves, individual leaf area, and petiole length were recorded. Biochemical parameters, such as chlorophyll a, chlorophyll b, total chlorophyll, carotenoid, and anthocyanin were analyzed. Fruit quality attributes such as total sugar, sucrose, glucose and fructose as well as yield-related traits including the number of fruit and total yield were also measured. Results and DiscussionBoth salicylic acid and boric acid significantly influenced plant growth, biochemical composition, and fruit yield. The highest leaf count (47.33) was observed with 0.5 mM salicylic acid and 0 mM boric acid, while the largest leaf area (306 cm2) was recorded with 0 mM salicylic acid and 2 mM boric acid. The maximum total chlorophyll content (12.11 and 10.8 mgg-1FW) was achieved with in 0 and 1 mM salicylic acid, respectively, combined with 2 mM boric acid. The highest sucrose (226.28 mg g FW-1) and fructose (87.9 mg g FW-1) contents were found in 1 mM salicylic acid without boric acid, while the highest glucose content (368.71 mg g FW-1) was recorded in 1mM salicylic acid with 2 mM boric acid. The greatest number of fruits (86.33) and the highest total fruit yield (9.59 kg plant-1; 21.10 kg m-2) were obtained with 0.5 mM salicylic acid combined with 2 mM boric acid. The lowest number of fruits (44) and yield (3.39 kg plant-1) were recorded in the control treatment. The lowest plant height of 189.3 cm was associated with 1 mM salicylic acid and 4 mM boric acid. The results showed that the highest petiole length with 15.66 cm was related to 0 mM salicylic acid, and 0.5 and 1 mM salicylic acid caused a decrease in petiole length with 14.88 and 14.33 cm, respectively. ConclusionSalicylic acid had a stronger effect on plant growth and yield than boric acid. However, their combined application produced better results than either treatment alone. The most effective treatment for optimizing cucumber growth and fruit yield was o.5 mM salicylic acid combined with 2 mM boric acid.
