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Irradiance from sunlight changes in a sinusoidal manner during the day, with irregular fluctuations due to clouds, and light–dark shifts at dawn and dusk are gradual. Experiments in controlled environments typically expose plants to constant irradiance during the day and abrupt light–dark transitions. To compare the effects on metabolism of sunlight versus artificial light regimes, Arabidopsis thaliana plants were grown in a naturally illuminated greenhouse around the vernal equinox, and in controlled environment chambers with a 12-h photoperiod and either constant or sinusoidal light profiles, using either white fluorescent tubes or light-emitting diodes (LEDs) tuned to a sunlight-like spectrum as the light source. Rosettes were sampled throughout a 24-h diurnal cycle for metabolite analysis. The diurnal metabolite profiles revealed that carbon and nitrogen metabolism differed significantly between sunlight and artificial light conditions. The variability of sunlight within and between days could be a factor underlying these differences. Pairwise comparisons of the artificial light sources (fluorescent versus LED) or the light profiles (constant versus sinusoidal) showed much smaller differences. The data indicate that energy-efficient LED lighting is an acceptable alternative to fluorescent lights, but results obtained from plants grown with either type of artificial lighting might not be representative of natural conditions.

Due to growing demands for sustainable food production, controlled-environment vertical farms (CEVFs) have emerged as promising systems for cultivating vegetables and herbs in urban areas. However, these systems are often criticized for their high energy consumption, largely influenced by artificial lighting. This study aimed to optimize white LED-based lighting by supplementing it with additional deep red (DR, 660 nm) and far red (FR, 730 nm) light, evaluating effects on the growth of lettuce ( Lactuca sativa cv. Batavia-Caipira) and basil ( Ocimum basilicum cv. Emily). Five treatments were tested, all using a white LED base spectrum (with blue, green, and red components), with varying levels of DR and FR. In one treatment, light intensity (PPFD) was doubled to 244 µmol·m ⁻2 ·s ⁻1 , while others were maintained at 122 µmol·m ⁻2 ·s ⁻1 . The high-PPFD treatment resulted in the highest biomass, increasing fresh weight by 76% in lettuce and 79% in basil compared to white light alone. Among the treatments with equal PPFD, supplemental FR increased leaf number and canopy size, while DR enhanced biomass. Chlorophyll and nitrogen contents were highest under white-only light. Correlation analysis showed that the intensity of added DR and FR significantly influenced plant responses. These results suggest targeted DR and FR supplementation improves light-use efficiency in CEVFs.

Proximal sensors in controlled environment agriculture (CEA) are used to monitor plant growth, yield, and water consumption with non-destructive technologies. Rapid and continuous monitoring of environmental and crop parameters may be used to develop mathematical models to predict crop response to microclimatic changes. Here, we applied the energy cascade model (MEC) on green- and red-leaf butterhead lettuce (Lactuca sativa L. var. capitata). We tooled up the model to describe the changing leaf functional efficiency during the growing period. We validated the model on an independent dataset with two different vapor pressure deficit (VPD) levels, corresponding to nominal (low VPD) and off-nominal (high VPD) conditions. Under low VPD, the modified model accurately predicted the transpiration rate (RMSE = 0.10 Lm−2), edible biomass (RMSE = 6.87 g m−2), net-photosynthesis (rBIAS = 34%), and stomatal conductance (rBIAS = 39%). Under high VPD, the model overestimated photosynthesis and stomatal conductance (rBIAS = 76–68%). This inconsistency is likely due to the empirical nature of the original model, which was designed for nominal conditions. Here, applications of the modified model are discussed, and possible improvements are suggested based on plant morpho-physiological changes occurring in sub-optimal scenarios.

Societal Impact Statement Cultivation of strawberry plants in urban production systems, whether in green open‐air spaces or under some form of protected horticulture such as vertical farming, has demonstrated to be challenging to new farmers and businesses. Commercial strawberry producers have an advanced understanding of strawberry plant physiology, enabling them to grow the crop successfully and profitably. Lack of knowledge exchange between commercial growers and new urban farmers seems to result in the abandonment of strawberries as crop of choice in urban systems. This review will confront the specific plant science challenges urban growers need to address to incorporate this nutritional crop into their revolutionary urban growing systems, whilst achieving good quality produce with high yields. Summary To ensure a sustainable future of farming, urban horticulture (UH) will need to be a key part of our everyday life. There are increasing demands for higher productivity and more locally produced food, even close to densely populated urban areas, to address environmental pressures and accelerate the resilience of modern food systems. UH is a broad term and can include numerous cultivation methods; rooftop gardens, public spaces, vertical walls, indoor vertical farms, as well as an array of crops including, salads, soft fruits and trees. Crops such as strawberries are expected to soon make a significant contribution to UH. Urban strawberry production promises all‐year round fruit availability, reduced reliance on imports, increased self‐sufficiency, lower food miles, a supply of high‐quality fresh fruits from hyper‐local spaces, increased employment opportunities, welfare benefits and an opportunity to promote a sense of community. Strawberry is a complex perennial crop with agronomical challenges, which requires specialist knowledge that is not always available to new urban farmers. Achieving an urban version of a strawberry field will require knowledge exchange between the commercial rural strawberry producers and the newly entered urban growers. Plant physiology, management of plant pathogens, choice of propagation material, fertigation, pollination and environmental requirements are the most common challenges for urban strawberry production. This review aims to consolidate the common bottleneck challenges of UH for new urban strawberry facilities. Cultivation of strawberry plants in urban production systems, whether in green open‐air spaces or under some form of protected horticulture such as vertical farming, has demonstrated to be challenging to new farmers and businesses. Commercial strawberry producers have an advanced understanding of strawberry plant physiology, enabling them to grow the crop successfully and profitably. Lack of knowledge exchange between commercial growers and new urban farmers seems to result in the abandonment of strawberries as crop of choice in urban systems. This review will confront the specific plant science challenges urban growers need to address to incorporate this nutritional crop into their revolutionary urban growing systems, whilst achieving good quality produce with high yields. El cultivo de plantas de fresa en sistemas de producción urbanos, ya sea en espacios agrícolas al aire libre o mediante alguna forma de horticultura controlada, como la agricultura vertical, ha demostrado ser un desafío para los nuevos agricultores y empresas. Los productores comerciales de fresas tienen un conocimiento detallado de la fisiología de las plantas de fresa, lo que les permite cultivar con éxito y de manera rentable. La falta de intercambio de conocimientos entre los productores comerciales y los nuevos agricultores urbanos, parece tener como resultado el abandono de las fresas como un cultivo preferido en los sistemas urbanos. Esta revisión aborda los desafíos específicos de la ciencia vegetal que los productores urbanos deben enfrentar para incorporar este cultivo nutritivo en sus revolucionarios sistemas de cultivo urbano, y al mismo tiempo lograr productos de buena calidad con altos rendimientos.

As of recent, microgreen vegetable production in controlled environments are being investigated for their bioactive properties. Phytochemicals like glucosinolates (GLS) are highly sensitive to varying spectral qualities of light, especially in leafy greens of Brassica where the responses are highly species-dependent. The accumulation of bioactive GLS were studied under 8 different treatments of combined amber (590 nm), blue (455 nm), and red (655 nm) light-emitting diodes (rbaLED). A semi-targeted metabolomics approach was carried out to profile common intact-GLS in microgreen extracts of Brassica by means of LC-HRMS/MS. Thirteen GLS were identified, among them were 8 aliphatic, 4 indolic and 1 aromatic GLS. Mass spectrometry data showed sinigrin had the highest average concentration and was highest in B. juncea , progoitrin was highest in B. rapa and glucobrassicin in R. sativus . The individual and total GLS in the microgreens of the present study were largely different under rbaLED; B. rapa microgreens contained the highest profile of total GLS, followed by R. sativus and B. juncea . Sinigrin was increased and gluconasturtiin was decreased under rbaLED lighting in most microgreens, glucoalyssin uniquely increased in R. sativus and decreased in B. rapa and glucobrassicin uniquely decreased in both B. rapa and B. juncea . The present study showed that rbaLED contributed to the altered profiles of GLS resulting in their significant modulation. Optimizing the light spectrum for improved GLS biosynthesis could lead to production of microgreens with targeted health-promoting properties. Graphical Abstract

Light-emitting diode (LED) technology is paving the way to increase crop production efficiency with electric lamps. Users can select specific wavelengths to elicit targeted photomorphogenic, biochemical, or physiological plants responses. In addition, LEDs can help control the seasonality of flowering plants to accurately schedule uniform flowering based on predetermined market dates. Research has shown that the monochromatic nature of LEDs can help prevent physiological disorders that are common in indoor environments, and help reduce incidence of pest and disease pressure in agriculture, which could ultimately increase crop production efficiency by preventing crop losses. Furthermore, a significant attribute of LED technology is the opportunity to reduce energy costs associated with electric lighting. Studies have shown that by increasing canopy photon capture efficiency and/or precisely controlling light output in response to the environment or to certain physiological parameters, energy efficiency and plant productivity can be optimized with LEDs. Future opportunities with LED lighting include the expansion of the vertical farming industry, applications for space-based plant growth systems, and potential solutions to support off-grid agriculture.

Assessing the total energy expenditure (TEE) and the levels of physical activity in free-living conditions with non-invasive techniques remains a challenge. The purpose of the present study was to investigate the accuracy of a new uniaxial accelerometer for assessing TEE and physical-activity-related energy expenditure (PAEE) over a 24 h period in a respiratory chamber, and to establish activity levels based on the accelerometry ranges corresponding to the operationally defined metabolic equivalent (MET) categories. In study 1, measurement of the 24 h energy expenditure of seventy-nine Japanese subjects (40 (SD 12) years old) was performed in a large respiratory chamber. During the measurements, the subjects wore a uniaxial accelerometer (Lifecorder; Suzuken Co. Ltd, Nagoya, Japan) on their belt. Two moderate walking exercises of 30 min each were performed on a horizontal treadmill. In study 2, ten male subjects walked at six different speeds and ran at three different speeds on a treadmill for 4 min, with the same accelerometer. O2 consumption was measured during the last minute of each stage and was expressed in MET. The measured TEE was 8447 (SD 1337) kJ/d. The accelerometer significantly underestimated TEE and PAEE (91·9 (SD 5·4) and 92·7 (SD 17·8) % chamber value respectively); however, there was a significant correlation between the two values (r 0·928 and 0·564 respectively; P<0·001). There was a strong correlation between the activity levels and the measured MET while walking (r2 0·93; P<0·001). Although TEE and PAEE were systematically underestimated during the 24 h period, the accelerometer assessed energy expenditure well during both the exercise period and the non-structured activities. Individual calibration factors may help to improve the accuracy of TEE estimation, but the average calibration factor for the group is probably sufficient for epidemiological research. This method is also important for assessing the diurnal profile of physical activity.

Berry fruits are well known to contain large amounts of polyphenol compounds. Among them, flavan-3-ol derivatives are a group of secondary metabolism compounds currently attracting a great deal of attention owing to their health benefits. Not only the fruits, but also the leaves of raspberry plants, are highly esteemed for tea making around the world and are largely used for food. In this report, we discuss the results of our study on the effect of light and temperature on polyphenol accumulation in raspberry leaves. When raspberry was cultivated in a plant factory unit and light intensity, wavelength, and temperature were varied, the amount of total polyphenol increased under blue light. Quantitative determination of (+)-catechin, (–)-epicatechin, procyanidin B4, flavan-3-ol trimer, which are flavan-3-ol derivatives, was carried out using HPLC, whereby we confirmed their increase under blue light. Semi-quantitative RT-PCR showed correlation between chalcone synthase (CHS) gene expression and the amounts of the compounds measured in the leaves.

1. The occurrence and intensity of climate extremes, such as extremely warm years, are expected to continue to increase with increasing tropospheric radiative forcing caused by anthropogenic greenhouse gas emissions. 2. Responses of terrestrial ecosystem processes and services - such as above-ground net primary productivity (ANPP) and maintenance of plant species diversity - to these extreme years for multiple years post-perturbation are poorly understood but can have significant feedback effects on net ecosystem CO₂ uptake and ecosystem carbon sequestration. 3. We exposed six 12 000-kg intact natural tallgrass prairie monoliths to an extremely warm year (+4 °C in 2003) in the second year of a 4-year study (2002-2005) using the EcoCELL whole-ecosystem controlled-environment, gas exchange facility. Six control monoliths were not warmed in the second year but were maintained under average field conditions. Natural diel and seasonal patterns in air temperature were maintained in both treatments throughout the study. Thus, with the exception of the second year in the 'warmed' treatment, we created 4 years of nearly identical climate in all EcoCELLs. 4. Interannual ANPP (10 cm clipping height) responses of the entire plant community to the extreme year were largely determined by responses of the dominant C₄ grasses. These included large decreases in ANPP in 2003 followed by complete recovery to levels observed in the control ecosystems in the year following warming. Species richness and productivity of the nitrogen-fixing plant functional group appeared to play a role in defining overall plant community ANPP, however, even though this richness and productivity could not explain the decrease in community ANPP observed in warmed ecosystems in the second year (2003) of the study or its recovery in the year after (2004). Surprisingly, very few of the 67 species present in plant communities during the 4-year study responded to the warm year at any time during or after the treatment. 5. Synthesis. Results from this study indicate that as extreme climate years become more prevalent, their immediate and lagged impacts on collective ecosystem processes, such as whole-community ANPP, may be very pronounced, but effects on component ecosystem processes may be limited to the dominant plant functional group (ANPP).

[This corrects the article DOI: 10.3389/fpls.2025.1650327.].