Greenhouse Plant Production Journal

Abstract Epibrassinolide (EBL) regulate plant development and environmental stress responses through complex signaling networks, yet optimization of exogenous 24-Epibrassinolide (EBL) application for commercial vegetable production remains underexplored. We investigated dose- and frequency-dependent effects of foliar 24-epibrassinolide (0, 0.5, and 0.75 μM) applied once (AR1) or twice (AR2) on eggplant (Solanum melongena L.) physiological performance, growth, and yield in a 3 × 2 factorial completely randomized design. Eggplant seeds were sown in a cocopeat and perlite growing medium at a ratio of 3:1 and the seedlings were watered daily in greenhouse. Foliar spraying was done in two stages before transplanting (four-leaf stage) in greenhouse and before flowering in farm. After the first foliar spray, the Eggplant seedlings were transplanted to the field and the plants were irrigated every three days throughout the growth period. Optimal EBL treatment (0.75 μM × AR2) elicited coordinated enhancement of photosynthetic capacity and membrane integrity. Chlorophyll metabolism was substantially upregulated, with SPAD values increasing 43%, total chlorophyll content rising 33.3%, and carotenoid accumulation elevated 82.7% compared to controls. Concurrently, cellular membrane stability improved markedly, evidenced by 43% reduction in electrolyte leakage. These physiological modifications translated into accelerated developmental progression 20.7–32.9% increase in vegetative growth and 17.8–21.7% advancement in flowering time culminating in approximately a two-fold increase in yield under the optimal regimen. Our findings demonstrate that strategic EBL application synchronously increased photosynthetic capacity and cellular homeostasis, establishing dual-spray 24-epibrassinolide treatment as an efficacious biostimulant strategy for Solanaceae crop intensification. Elucidating the underlying molecular pathways particularly EBL receptor dynamics and downstream transcriptional cascades—represents a critical next step for optimizing this approach across diverse genotypes and environmental conditions.

Abstract Greenhouse cultivation in Iran has expanded significantly, yet the influence of greenhouse structural characteristics on the efficacy of pest management remains poorly understood. This study evaluated the efficacy of four commonly used acaricides, abamectin, bifenazate, hexythiazox, and spirodiclofen, against the two-spotted spider mite (Tetranychus urticae Koch) in two distinct greenhouse structural types: gothic multispan (height: 600 cm, fan-and-pad ventilation) and wood-framed (height: 223-245 cm, hand-operated ventilation). The experiments were conducted in four cucumber greenhouses in Isfahan Province, Iran, during July 2022. Acaricides were applied at recommended concentrations, and mite mortality was assessed at 3, 7, and 14 days after treatment (DAT) using the Henderson-Tilton formula. Results revealed significantly higher acaricide efficacy in gothic multispan greenhouses compared with wood-framed structures across all sampling intervals. At 14 DAT, the highest efficacy recorded in gothic greenhouses (bifenazate: 85.22%) was nearly double that observed in wood-framed structures (43.27%). Bifenazate and hexythiazox demonstrated superior residual activity (85.22% and 79.10% at 14 DAT in gothic greenhouses, respectively), while abamectin and spirodiclofen exhibited the lowest persistence, particularly in wood-framed structures (33.95% and 30.98% at 14 DAT, respectively). The reduced efficacy observed in wood-framed greenhouses may be associated with suboptimal environmental conditions, including inadequate ventilation, poor air circulation, and limited spray coverage due to lower height. The findings suggest that investing in modern greenhouse infrastructure can substantially improve acaricide performance, potentially reducing spray frequency and delaying resistance development. However, as this study focused exclusively on chemical control, future research should investigate the compatibility of these findings with biological control agents within integrated pest management programs.

Abstract Rising food demand and the push for decarbonization have made controlled-environment agriculture essential. However, its energy intensity, especially in arid regions, hinders sustainability. This paper introduces the predictive-adaptive coordinated optimization (PACO) framework, a novel control architecture for demand-side energy management in networks of grid-interfaced greenhouses. Departing from population-based metaheuristics, PACO is rigorously grounded in adaptive control theory, recursive online estimation, and distributed optimization. Each greenhouse agent employs an adaptive autoregressive exogenous model with recursive least-squares parameter updating, enabling continuous tracking of seasonal variations, equipment degradation, and sensor drift. A novel correction mechanism, with gains dynamically scheduled based on prediction error and battery state-of-charge, provides robust compensation for forecast mismatches and unforeseen disturbances. An attention-based coordination unit computes lightweight scalar signals that promote global demand flattening without imposing centralized optimization during execution. The framework explicitly enforces physical constraints through penalty-augmented objectives and entropy regularization. Extended simulations, including 30-day horizon, multi-seasonal assessments, and ablation studies on a 10-greenhouse network in a semi-arid climate, demonstrate that PACO reduces total grid import by 29.8%, shaves peak demand by 31.1%, cuts operational costs by 32.9%, and lowers CO₂ emissions by 29.7% compared to benchmark methods, while confirming the synergistic contributions of its three core components. PACO offers a transparent, scalable, and computationally efficient solution for coordinated multi-greenhouses, bridging the gap between physical modeling and online adaptation.

Abstract This study was conducted to evaluate the effect of different urea concentrations on vegetative growth, leaf physiological traits, biochemical characteristics, and fruit quality of container-grown blueberry (Vaccinium corymbosum L. cv. Jewel). The experiment was arranged in a completely randomized design with four concentrations of added urea (5, 4, 3, and 2 mmol L⁻¹) supplied in a basal nutrient solution containing 1 mmol L⁻¹ KNO₃^- Analysis of variance revealed that urea concentration significantly affected SPAD value, leaf nitrogen content, chlorophyll a, chlorophyll b, total chlorophyll, and carotenoids at p < 0.01, while total fruit fresh weight and antioxidant activity (%DPPH) were significant at p < 0.05. Although urea concentration significantly influenced flower number per bush, fruit number per inflorescence, total fruit weight, fruit number per bush, and yield per bush, the responses were not uniform across all reproductive traits and urea levels. These results indicate that blueberry responses to urea were expressed mainly through changes in leaf nitrogen status, pigment accumulation, and antioxidant capacity rather than through major alterations in plant architecture or basic fruit composition. Overall, the findings suggest that moderate variation in urea concentration can effectively influence physiological and biochemical performance in blueberry without adversely affecting fruit quality. Under the conditions of this experiment, added urea concentration affected growth, physiological traits, nutrient status, reproductive performance, and fruit-quality attributes of container-grown highbush blueberry cv. ‘Jewel’.

Abstract Greenhouse cultivation is recognized as an effective strategy for enhancing water productivity; however, its success depends on model-based estimation of crop water requirements under regional climatic conditions. To date, no comprehensive study has been conducted on water requirements of greenhouse crops in Alborz Province. This study estimated net water requirements for ten major greenhouse crops in Alborz Province (solanaceous crops, leafy vegetables, and strawberry) using long-term meteorological data from nine weather stations. Reference evapotranspiration was calculated using the Almeria radiation (AR) and solar radiation (SR) methods, with crop coefficients applied to determine net requirements. Spatial patterns and method agreement were evaluated using boxplots, heatmaps, and regression. The results indicated that annual water requirements ranged from 833.8 to 1,189.7 mm, with bell pepper exhibiting the highest and cucumber the lowest requirements. Among solanaceous crops, bell pepper and eggplant showed the highest values and cucumber the lowest, while among leafy vegetables, cabbage exhibited the highest requirement and basil the lowest. A clear spatial gradient was observed, with Eshtehard, Nazarabad, and Meshkin Dasht showing the highest requirements, and Asara, Taleqan, Payam Airport, and Zidasht the lowest. The AR method consistently produced higher estimates than SR, while both methods showed similar spatial patterns and strong correlation. This study provides the first comprehensive database of estimated water requirements for major greenhouse crops in Alborz Province, serving as a preliminary reference for irrigation planning, water allocation, greenhouse licensing, and sustainable development in the region.

Abstract Low-temperature is one of the environmental stresses that affect the growth, development and performance of the grapevine. Nitric oxide (NO) is a relatively stable gas radical that prevents the production of reactive oxygen radicals at low concentrations. The present study aimed to investigate the physiological changes created in response to the foliar application of NO (0, 100 and 200 µM) in Yaghooti variety grape plants under two temperature treatments (24 ºC and 4ºC) in greenhouse conditions as a factorial experiment based on a completely randomized design. Based on the results, the application of NO increased the membrane stability in the leaf cells of the treated vines, which documented by lower ion leakage and malondialdehyde content in the vines sprayed with this growth regulator under low-temperature stress. On the other hand, in vines under low-temperature stress, the use of NO resulted in maintaining the concentration of chlorophyll, increasing the content of proline, total soluble sugar, total phenol, total flavonoid, soluble proteins and also caused a significant increase in the activity of antioxidant enzymes under low-temperature stress. By affecting compatible osmolytes, antioxidant enzymes, nutritional elements such as magnesium and iron, NO increased the tolerance of grape plants under low-temperature stress conditions. According to the results, foliar spray of NO especially at 200 µM is recommended to increase tolerance to low-temperature stress in grapes.