Search Results (954)

The inclusion of the Internet of Things (IoT) in indoor agricultural systems has become a fundamental tool for improving cultivation systems by providing key information for decision-making in pursuit of better performance. This article presents the design and implementation of an IoT-based agricultural system installed in a plant growth chamber for hydroponic cultivation under controlled conditions. The growth chamber is equipped with sensors for air temperature, relative humidity (RH), carbon dioxide (CO₂) and photosynthetically active photon flux, as well as control mechanisms such as humidifiers, full-spectrum Light Emitting Diode (LED) lamps, mini split air conditioner, pumps, a Wi-Fi surveillance camera, remote monitoring via a web application and three Nutrient Film Technique (NFT) hydroponic systems with a capacity of ten plants each. An ATmega2560 microcontroller manages the smart system using the MODBUS RS-485 communication protocol. To validate the proper functionality of the proposed system, a case study was conducted using lettuce crops, in which the impact of different nutrient solution concentrations (50%, 75% and 100%) on the phenotypic development and nutritional content of the plants was evaluated. The results obtained from the cultivation experiment, analyzed through analysis of variance (ANOVA), show that the treatment with 75% nutrient concentration provides an appropriate balance between resource use and nutritional quality, without affecting the chlorophyll content. This system represents a scalable and replicable alternative for protected agriculture. Full article

Atriplex hortensis var. rubra (red orache, RO) is a halotolerant species rich in nutraceutical compounds, which makes it a valuable crop for human nutrition. This plant could also be exploited for phytoremediation of contaminated soil and wastewater, and for saline aquaponics. A root rot disease was observed on hydroponically grown RO plants, caused by Pythium deliense and Pythium Cluster B2a sp. Identification was based on morphology, molecular analysis (ITS and COI), and phylogenetic analysis. We assessed disease severity in plants grown in a growth chamber with nutrient solutions containing different NaCl concentrations (0, 7, and 14 g L⁻¹ NaCl). In vitro growth at different salinity levels and temperatures was also evaluated. Both Pythium species were pathogenic but showed different responses. Pythium deliense was significantly more virulent than Pythium Cluster B2a sp., causing a steady reduction in root dry weight (RDW) of 70% across all salinity levels. Pythium Cluster B2a sp. reduced RDW by 50% at 0 and 7 g L⁻¹ NaCl while no symptoms were observed at 14 g L⁻¹ NaCl. Pythium deliense grew best at 7 and 14 g L⁻¹ NaCl, while Pythium Cluster B2a sp. growth was reduced at 14 g L⁻¹ NaCl. Both pathogens had an optimum temperature of 30 °C. This is the first report of Pythium spp. causing root rot on RO grown hydroponically. The effective use of halophytic crops must consider pathogen occurrence and fitness in saline conditions. Full article

This study investigates the viability of a native Scenedesmus sp. strain for use in a 50 L bubble column photobioreactor designed to reduce greenhouse gas emissions under simulated spring, extreme summer, and winter conditions. The experiments were conducted by placing the reactor in a controlled climatic chamber, which allowed us to regulate the temperature, light intensity, and day–night cycles throughout the entire experiment. The results showed that under simulated spring conditions (a maximum temperature of 22 °C), the algal culture grew continuously for 61 days. Under extreme summer conditions (a maximum temperature of 39 °C), an initial drop in cell density was followed by recovery and continued growth over 75 days, although biomass production was 35% lower. Under winter conditions (a maximum temperature of 10 °C), the culture failed, indicating the need to prevent temperatures below 10 °C. In terms of biomass production, the culture densities achieved were 1.04 g L⁻¹ and 0.68 g L⁻¹ in the spring and summer trials, respectively. The Scenedesmus sp. strain demonstrated high carbon capture efficiency, tolerance to extreme heat, and sustained growth without the need for fresh medium or pH adjustments for over 60 days during spring and extreme summer conditions, confirming its potential for outdoor applications. Full article

The chickpea (Cicer arietinum L.) is a key legume crop in Mediterranean agriculture, valued for its nutritional profile and adaptability. However, its productivity is severely impacted by drought stress. To identify microbial solutions that enhance drought resilience, we isolated seven Mesorhizobium strains from chickpea nodules collected in southern Spain and evaluated their cultivar-specific symbiotic performance. Two commercial cultivars (Pedrosillano and Blanco Lechoso) and twenty chickpea germplasms were tested under growth chamber and greenhouse conditions, both with and without drought stress. Initial screening in a sterile substrate using nodulation assays, shoot/root dry weight measurements, and acetylene reduction assays identified three elite strains (ISC11, ISC15, and ISC25) with superior symbiotic performance and nitrogenase activity. Greenhouse trials under reduced irrigation demonstrated that several strain–cultivar combinations significantly mitigated drought effects on plant biomass, with specific interactions (e.g., ISC25 with RR-98 or BT6-19) preserving over 70% of shoot biomass relative to controls. Whole-genome sequencing of the elite strains revealed diverse taxonomic affiliations—ISC11 as Mesorhizobium ciceri, ISC15 as Mesorhizobium mediterraneum, and ISC25 likely representing a novel species. Genome mining identified plant growth-promoting traits including ACC deaminase genes (in ISC11 and ISC25) and genes coding for auxin biosynthesis-related enzymes. Our findings highlight the potential of targeted rhizobial inoculants tailored to chickpea cultivars to improve crop performance under water-limiting conditions. Full article

High nighttime temperature (HNT) due to asymmetric diurnal warming threatens wheat productivity. This study evaluated the effect of HNT on wheat phenology, physiology, and yield through field and controlled environment experiments in Central Queensland, Australia. Two wheat genotypes, Faraday and AVT#6, were assessed under three sowing dates—1 May (Early), 15 June (Mid), and 1 August (Late)—within the recommended sowing window for the region. In a parallel growth chamber study, the plants were exposed to two nighttime temperature regimes, of 15 °C (normal) and 20 °C (high), with consistent daytime conditions from booting to maturity. Late sowing resulted in shortened vegetative growth and grain filling periods and increased exposure to HNT during the reproductive phase. This resulted in elevated floret sterility, lower grain weight, and up to 40% yield loss. AVT#6 exhibited greater sensitivity to HNT despite maturing earlier. Leaf gas exchange analysis revealed increased nighttime respiration (Rn) and reduced assimilation (A), resulting in higher Rn/A ratio for late-sown crops. The results from controlled environment chambers resembled trends of the field experiment, producing lower grain yield and biomass under HNT. Cumulative nighttime hours above 20 °C correlated more strongly with yield losses than daytime heat. These findings highlight the need for HNT-tolerant genotypes and optimized sowing schedules under future climate scenarios. Full article

Peatlands store substantial amounts of carbon (C) in the form of peat, but are increasingly threatened by drought and shrub encroachment under climate warming. However, how peat decomposition and its temperature sensitivity (Q₁₀) vary with depth and plant litter input under these stressors remains poorly understood. We incubated peat from two depths with different degrees of decomposition, either alone or incubated with Sphagnum divinum shoots or Betula ovalifolia leaves, under five temperature levels and two moisture conditions in growth chambers. We found that drought and Betula addition increased CO₂ emissions in both peat layers, while Sphagnum affected only shallow peat. Deep peat alone or with Betula exhibited higher Q₁₀ than pure shallow peat. Drought increased the Q₁₀ of both depths’ peat, but this effect disappeared with fresh litter addition. The CO₂ production rate showed a positive but marginal correlation with microbial biomass carbon, and it displayed a rather similar responsive trend to warming as the microbial metabolism quotient. These results indicate that both deep and dry peat are more sensitive to warming, highlighting the importance of keeping deep peat buried and waterlogged to conserve existing carbon storage. Additionally, they further emphasize the necessity of Sphagnum moss recovery following vascular plant encroachment in restoring carbon sink function in peatlands. Full article

In the present study, we evaluated the potential use of a humic substance (HS)-based biostimulant in mitigating drought stress in lettuce (Lactuca sativa L.) by comparing both root and foliar modes of application. To achieve this, lettuce plants were grown in a growth chamber on a solid substrate composed of vermiculite and perlite (3:1). Plants were exposed to drought conditions (50% of Field Capacity, FC) and 50% FC + HS applied as radicular (‘R’) and foliar (‘F’) at concentrations: R-HS 0.40 and 0.60 mL/L, respectively, and 7.50 and 10.00 mL/L, respectively, along with a control (100% FC). HSs were applied three times at 10-day intervals. Plant growth, nutrient concentration, lipid peroxidation, reactive oxygen species (ROS), and enzymatic and non-enzymatic antioxidants were estimated. Various photosynthetic and chlorophyll fluorescence parameters were also analyzed. The results showed that HS applications alleviated drought stress, increased plant growth, and reduced lipid peroxidation and ROS accumulation. HSs also improved the net photosynthetic rate, carboxylation efficiency, electron transport flux, and water use efficiency. Although foliar HSs showed a greater tendency to enhance shoot growth and photosynthetic capacity, the differences between the application methods were not significant. Hence, in this preliminary work, the HS-based product evaluated in this study demonstrated potential for alleviating drought stress in lettuce plants at the applied doses, regardless of the mode of application. This study highlights HS-based biostimulants as an effective and sustainable tool to improve crop resilience and support sustainable agriculture under climate change. However, further studies under controlled growth chamber conditions are needed to confirm these results before field trials. Full article

Hydraulic shear has been widely accepted as one of the essential factors modulating phytoplankton growth. Previous experimental studies of algal growth have been conducted at the macroscopic level, and direct observation at the cell scale has been lacking. In this study, an algal-cell dynamic continuous observation platform (ACDCOP) is proposed with a parallel-plate flow chamber (PPFC) to capture cellular growth images which are then used as input to a computer vision algorithm featuring a pre-trained backpropagation neural network to quantitatively evaluate the volumes and volumetric growth rates of individual cells. The platform was applied to investigate the growth of Scenedesmus quadricauda cells under different hydraulic shear stress conditions. The results indicated that the threshold shear stress for the development of Scenedesmus quadricauda cells was 270 µL min⁻¹ (5.62 × 10⁻⁵ m² s⁻³). Cellular growth was inhibited at very low and very high intensities of hydraulic shear. Among all the experimental groups, the longest growth period for a cell, from attachment to PPFC to cell division, was 5.7 days. Cells with larger initial volumes produced larger volumes at division. The proposed platform could provide a novel approach for algal research by enabling direct observation of algal growth at the cell scale, and could potentially be applied to investigate the impacts of various environmental stressors such as nutrient, temperature, and light on cellular growth in different algal species. Full article

Ozone pollution decreases rice yield and quality in general, but how ozone stress changes grain-filling capacity is unclear. A chamber experiment was conducted to compare the effects of ozone exposure during the rice growth season on the grain-filling capacity and quality of spikelets located on the upper primary rachis (superior spikelets, SS) and the lower secondary rachis (inferior spikelets, IS). Ozone stress significantly decreased filled grain percentage by 41.4% and grain mass by 10.2% in IS, but had little effect on grain-filling capacity in SS. Consistent with the reduction in grain mass, ozone stress decreased grain volume, mainly due to reduced grain thickness, and IS was reduced more than SS. After removing the hull, brown rice obtained from ozone treatment exhibited higher proportions of immature and abnormal kernels, resulting in a substantially lower proportion of perfect kernels. Under ozone stress, the proportion of perfect kernels was only one-third in IS, compared with two-thirds in SS. Ozone stress affected the pasting properties of brown rice for both SS and IS, as shown by the decreased amylose content, and the increased maximum viscosity, minimum viscosity, final viscosity, setback, and peak time of the rapid visco analyzer profile. Out of fourteen traits related to nutritional quality of brown rice, only five showed significant increases under ozone stress, and they were the concentrations of albumin, prolamin, sulfur, copper, and manganese. The differential ozone responses between SS and IS were rather small for rice pasting properties and chemical compositions as shown by very few significant interactions between ozone and grain position. It is concluded that ozone stress during plant growth imposed more adverse effects on IS than SS in terms of grain-filling capacity and appearance quality, suggesting an enlarged asynchronous grain-filling pattern in rice panicles under ozone pollution. Strategies to improve the grain-filling capacity of IS are needed to mitigate ozone-induced damage to rice production. Full article

Mabroom dates (Phoenix dactylifera L.) are recognized as one of the most important crops in Qatar. Fresh fruit dates are susceptible to mould and post-harvest spoilage, resulting in a significant financial loss. Octanoic fatty acid (OFA) has been shown to regulate the growth of mould-causing organisms such as fungi and bacteria. It is known to have antibacterial properties. The objective of the current study was to evaluate the in vitro effect of OFA on the post-harvest pathogens of Mabroom fruits. Fresh, apparently healthy, and fully ripe Mabroom dates were obtained from the National Agriculture and Food Corporation (NAFCO). The chosen fruits were packed in sterile, well-ventilated plastic boxes and transported to the lab under controlled conditions. The fruits were distributed into five groups (G1 to G5). The groups G1, G2, and G3 received 1%, 2%, and 3.5% OFA, respectively, while G4 was left untreated and G5 was washed only with tap water as a positive control treatment. Each group contained 200 g of fresh and healthy semi-soft dates. The samples were then dried and incubated in a humidity chamber at 25 °C ± 2 for seven days. The signs and symptoms of decay were monitored and recorded. The presence of pathogens was confirmed via phenotypic and microscopic-based methods. The results showed a significant difference (p ≤ 0.05) among the groups. OFA at 3.5% had the strongest inhibitory action against post-harvest pathogens, followed by OFA2%. However, there were no differences (p ≤ 0.05) between OFA1% and the control groups. Aspergillus spp., Penicillium spp., Rhizopus spp., and Botrytis spp. were most abundant in the control group, followed by OFA2% and OFA1%, respectively. In conclusion, octanoic fatty acid at 3.5% may improve the quality of date fruits through its high antimicrobial activity, reduce the effect of post-harvest decay, minimize the loss of date fruits during storage, and improve the sustainability of date fruits. Further experiments are necessary to confirm the effectiveness of OFA as a green solution for sustainable date fruit production. Full article

The field of metal additive manufacturing has witnessed significant growth in recent years, with technology offering the ability to produce complex geometries that are challenging to manufacture using the traditional methods. In situ monitoring and control of the manufacturing process are crucial for increasing the production capacity and improving the quality of manufactured parts. This article provides a comparative analysis of computational, indirect, and direct methods for in situ temperature monitoring during additive manufacturing of metal alloy components. Furthermore, it discusses the current status, recent improvements, and perspectives for in situ temperature measurements. The basic principles of thermal imaging, two-color pyrometry, and millimeter-wave radiometry are explored, highlighting their limitations for addressing challenges related to material emissivity and rapid changes in building material composition. Overcoming the challenges related to the inaccessibility of the chamber where the parts are formed, direct temperature measurements would allow for the integration of collected information into big data systems. Within the framework of Industry 4.0, this approach offers a viable alternative to the conventional metal shaping processes, improving the production capacity and part quality. This research aims to contribute to ongoing advancements in metal additive manufacturing and its potential to completely replace traditional metal casting practices in the Industry 4.0 era. Full article

Creeping bentgrass (Agrostis stolonifera L.) is an important cool-season turfgrass species widely used for golf course putting greens; however, it experiences a summer stress-induced quality decline in the U.S. transition zone and other regions with similar climates. The objective of this study was to determine the effects of five amino acid biostimulants on creeping bentgrass drought and heat stress tolerance. The five biostimulants, including Superbia, Amino Pro V, Siapton, Benvireo, and Surety, at the rate of 0.22 g of N m⁻², were applied biweekly to foliage, and the treatments were arranged in a randomized block design with four replications and were subjected to 56 days of heat and drought stress in growth chamber conditions. The amino acid biostimulants Superbia and Amino Pro V improved the turf quality, photochemical efficiency (PE), normalized difference vegetation index (NDVI), chlorophyll content, antioxidant enzyme superoxide dismutase activity, root growth, and viability and suppressed leaf H₂O₂ levels when compared to a control. Among the treatments, Superbia and Amino Pro V exhibited greater beneficial effects on turf quality and physiological fitness. The results of this study suggest that foliar application of amino acid biostimulants may improve the summer stress tolerance of cool-season turfgrass species in the U.S. transition zone and other regions with similar climates. Full article

Plants are continuously exposed to multiple environmental stressors throughout their lifecycle. Understanding their integrated physiological, biochemical, and anatomical responses under combined stress conditions is crucial for developing effective approaches to improve stress tolerance and maintain crop productivity. This study aimed to investigate the physiological, biochemical, and anatomical changes in photomorphogenic Micro-Tom plants exposed to high irradiance and water deficit—an abiotic stress combination that commonly co-occurs in natural environments but remains poorly understood in light-sensitive genotypes. We hypothesized that the high pigment 1 (hp1) mutant, due to its enhanced light responsiveness, would display improved stress acclimation compared to the wild-type when exposed to combined stress factors. This study was conducted in a controlled plant growth chamber, using a randomized block design with five replicates. Two Micro-Tom genotypes (wt and hp1) were exposed to control (soil at field capacity (FC) + 450 μmol m⁻² s⁻¹ PPFD) and combined stress (40% FC + 1800 μmol m⁻² s⁻¹ PPFD) conditions. Despite the higher concentration of chloroplast pigments in hp1, its photosynthetic performance under combined stress was not significantly improved, and its defense mechanisms did not effectively mitigate the stress impacts. Anatomically, wt exhibited greater structural adjustment, observed by adaptations in the spongy parenchyma and mesophyll. Overall, the wt genotype showed stronger defense mechanisms, while hp1 was more susceptible to combined abiotic stress. Full article

It is necessary to explore possibilities to increase agricultural production in environmentally friendly ways while maintaining the quality standards of plant raw materials. The effect of amino acids on sweet basil (Ocimum basilicum L.) development may stimulate biomass accumulation and enhance the biosynthesis of secondary metabolites. Investigated varieties “Rosie”, “Red Opal”, “Bordeaux”, “Dark Opal”, “Red Rubin”, “Genovese”, “Cinamon”, “Italiano Classico”, “Marseillais”, and “Thai” were cultivated in a controlled-environment growth chamber and the impact of isoleucine, methionine, glutamine, tryptophan, phenylalanine was studied on biomass accumulation, chlorophyll and phenolic content, and antioxidant activity. Five to six true leaves plants were treated once with an aqueous solution containing 100 mg L⁻¹ of the mentioned amino acids or received no treatment. Our results show that methionine or tryptophan improved the most fresh and dry weight of shoot system of sweet basil plants. Methionine increased chlorophyl a content in 6 of 10 sweet basil varieties, while glutamine had the greatest results in chlorophyl b content. Phenylalanine increased total phenolic content in most treated plants, as well as antioxidant activity. Amino acids may be applied as useful biostimulants in modern agriculture, as they play an important role in ensuring sustainable crop productivity, fostering beneficial plant properties. Full article

It is projected that the world population will quadruple over the next century, and to meet future food demands, agricultural production will need to increase by 70%. Therefore, there has been a transition from traditional farming methods to autonomous modern agriculture. One such modern technique is aeroponic farming, in which plants are grown without soil under controlled and hygienic conditions. In aeroponic farming, plants are significantly less affected by climatic conditions, infectious diseases, and biotic and abiotic stresses, such as pest infestations. Additionally, this method can reduce water, nutrient, and pesticide usage by 98%, 60%, and 100%, respectively, while increasing the yield by 45–75% compared to traditional farming. In this study, a three-dimensional industrial design of an innovative aeroponic plant growth chamber was presented for use by individuals, researchers, and professional growers. The proposed chamber design is modular and open to further innovation. Unlike existing chambers, it includes load cells that enable real-time monitoring of the fresh weight of the plant. Furthermore, cameras were integrated into the chamber to track plant growth and changes over time and weight. Additionally, RGB power LEDs were placed on the inner ceiling of the chamber to provide an optimal lighting intensity and spectrum based on the cultivated plant species. A customizable chamber design was introduced, allowing users to determine the growing tray and nutrient nozzles according to the type and quantity of plants. Finally, system models were developed for temperature control of the chamber. Temperature control was implemented using a proportional-integral-derivative controller optimized with particle swarm optimization, radial movement optimization, differential evolution, and mayfly optimization algorithms for the gain parameters. The simulation results indicate that the temperatures of the growing and feeding chambers in the cabinet reached a steady state within 260 s, with an offset error of no more than 0.5 °C. This result demonstrates the accuracy of the derived model and the effectiveness of the optimized controllers. Full article