Controlled Environment Chambers Research Articles

Collection, Expansion, and Differentiation of Primary Human Nasal Epithelial Cell Models for Quantification of Cilia Beat Frequency.

Measurements of cilia function (beat frequency, pattern) have been established as diagnostic tools for respiratory diseases such as primary ciliary dyskinesia. However, the wider application of these techniques is limited by the extreme susceptibility of ciliary function to changes in environmental factors e.g., temperature, humidity, and pH. In the airway of patients with Cystic Fibrosis (CF), mucus accumulation impedes cilia beating. Cilia function has been investigated in primary airway cell models as an indicator of CF Transmembrane conductance Regulator (CFTR) channel activity. However, considerable patient-to-patient variability in cilia beating frequency has been found in response to CFTR-modulating drugs, even for patients with the same CFTR mutations. Furthermore, the impact of dysfunctional CFTR-regulated chloride secretion on ciliary function is poorly understood. There is currently no comprehensive protocol demonstrating sample preparation of in vitro airway models, image acquisition, and analysis of Cilia Beat Frequency (CBF). Standardized culture conditions and image acquisition performed in an environmentally controlled condition would enable consistent, reproducible quantification of CBF between individuals and in response to CFTR-modulating drugs. This protocol describes the quantification of CBF in three different airway epithelial cell model systems: 1) native epithelial sheets, 2) air-liquid interface models imaged on permeable support inserts, and 3) extracellular matrix-embedded three-dimensional organoids. The latter two replicate in vivo lung physiology, with beating cilia and production of mucus. The ciliary function is captured using a high-speed video camera in an environment-controlled chamber. Custom-built scripts are used for the analysis of CBF. Translation of CBF measurements to the clinic is envisioned to be an important clinical tool for predicting response to CFTR-modulating drugs on a per-patient basis.

Preparation of tourmaline/diatomite-based interior wall bricks and kinetics of formaldehyde removal

Diatomite was used as the main raw material, to which tourmaline powder and sintering additives were added, using an ultra-fine wet grinding process to prepare glaze slurry, and impregnating the surface and pore channel of diatomite-based porous ceramics, tourmaline/diatomite-based interior wall bricks were prepared by low-temperature calcination. The adsorption and degradation abilities of the materials were discussed by using formaldehyde gas as the target pollutant. Results indicate that the tourmaline/diatomite-based inner wall bricks, the original pore structure of diatomite, and the pores formed by particle accumulation constitute an organic whole. After 16% ultrafine tourmaline powder was added to the glaze layer, the average pore diameter and porosity decreased from 4243.8 nm and 45.5% to 2814.5 nm and 41.8% respectively, while the specific surface area increased from 6.14 m2/g to 8.62 m2/g. In a 1-m3 controlled-environment chamber, after 5 h of purification, the concentration of formaldehyde decreased from 0.303 mg/m3 to 0.0782 mg/m3. Based on the Langmuir-Hinshelwood model, the kinetic equation of formaldehyde adsorption in its gas phase was established. The reaction rate constants of formaldehyde gas phase adsorption degradation were obtained by linear regression as follows: κ = 0.483 mg/(m3·min), and the apparent rate constant K = 0.036 m3/mg.

Influence of CNT Incorporation on the Carbonation of Conductive Cement Mortar

This study analyzed the influence of carbon nanotubes (CNTs) on the carbonation conductive cementitious composites. Two powder types of CNT, multi-walled and single-wall CNTs, were employed to give the cement mortar the conductivity, and four tests including the accelerated carbonation, compressive and flexural strength, electrical resistance, and porosity tests were carried out. To intentionally accelerate the carbonation, the prismatic specimens of conductive cement composites were fabricated and stored in the controlled environmental chamber at a constant temperature of 20 ± 2 °C, constant relative humidity of 60 ± 5%, and carbon dioxide (CO2) concentration of 5% for 12 weeks. It was observed that carbonation resulted in only chemical damage so that there was no change in the electrical resistance value of conductive cementitious mortar that had undergone a carbonation attack.

Lung tissue phantom mimicking pulmonary optical properties, relative humidity, and temperature: a tool to analyze the changes in oxygen gas absorption for different inflated volumes

.SignificanceGas in scattering media absorption spectroscopy (GASMAS) enables noninvasive gas sensing in the body. It is developing as a tool for diagnosis and monitoring of respiratory conditions in neonates. Phantom models with relevant features to the clinical translation of GASMAS technology are necessary to understand technical challenges and potential applications of this technique. State-of-the-art phantoms designed for this purpose have focused on the optical properties and anthropomorphic geometry of the thorax, contributing to the source–detector placement, design, and optimization. Lung phantom mimicking the alveolar anatomy has not been included in the existent models due to the inherent complexity of the tissue. We present a simplified model that recreates inflated alveoli embedded in lung phantom.AimThe goal of this study was to build a lung model with air-filled structures mimicking inflated alveoli surrounded by optical phantom with accurate optical properties ( and ) and physiological parameters [37°C and 100% relative humidity (RH)], and to control the air volume within the phantom to demonstrate the feasibility of GASMAS in sensing changes in pulmonary air volume.ApproachThe lung model was built using a capillary structure with analogous size to alveolar units. Part of the capillaries were filled with liquid lung optical phantom to recreate scattering and absorption, whereas empty capillaries mimicked air filled alveoli. The capillary array was placed inside a custom-made chamber that maintained pulmonary temperature and RH. The geometry of the chamber permitted the placement of the laser head and detector of a GASMAS bench top system (MicroLab Dual ), to test the changes in volume of the lung model in transmittance geometry.ResultsThe lung tissue model with air volume range from to was built. Two measurement sets, with 10 different capillary configurations each, were arranged to increase or decrease progressively (in steps of ) the air volume in the lung model. The respective GASMAS data acquisition was performed for both data sets. The maximum absorption signal was obtained for configurations with the highest number of air-filled capillaries and decreased progressively when the air spaces were replaced by capillaries filled with liquid optical phantom. Further studies are necessary to define the minimum and maximum volume of air that can be measured with GASMAS-based devices for different source–detector geometries.ConclusionsThe optical properties and the structure of tissue from the respiratory zone have been modeled using a simplified capillary array immersed in a controlled environment chamber at pulmonary temperature and RH. The feasibility of measuring volume changes with GASMAS technique has been proven, stating a new possible application of GASMAS technology in respiratory treatment and diagnostics.

Determining the impact of sensor orientation on moisture content measurements in eastern white pine

As buildings become more airtight and insulated, the movement and accumulation of moisture within building envelopes become paramount in determining its resiliency. Current methods for quantifying the moisture content (MC) of wood species involve the measurement of electrical resistance between two installed electrodes and the use of existing empirical correlations to evaluate the MC. However, these correlations do not adequately consider the impact of sensor orientation within wall assemblies. The objective of this paper is to determine the impact of MC readings within a wood sample due to sensor orientation. A total of 126 eastern white pine samples were tested with electrodes placed along the grain of the wood (longitudinal), across the grain of the wood (tangential), and in a diamond pattern, using six different fasteners as electrodes. The samples were placed in a controlled environmental chamber until steady state was achieved at approximately 18% MC. Electrical resistances of the samples were measured in both directions at temperatures ranging from -10°C to 40°C. It was found that the tangential-to-longitudinal resistance ratio is 1.1-1.35 depending on the electrode type.

The Combined Effects of Precision-Controlled Temperature and Relative Humidity on Artificial Ripening and Quality of Date Fruit.

Due to climatic variation, in-situ date palm fruit ripening is significantly delayed, and some fruits (Biser) cannot become ripe naturally on the tree. Because of that issue, the vast quantity of produce is mere wasted. Few traditional methods are adopted to ripe these unripe fruits through open sun drying or solar tunnel dehydration techniques. However, these methods have minimal use due to ambient temperature and relative humidity (RH) instability. Therefore, the present study was designed to find a precise combination of temperature and RH to artificially ripe the unripe Biser fruits under controlled environment chambers. For that purpose, eighteen automated artificial ripening systems were developed. The Biser fruits (cv. Khalas) were placed immediately after harvesting in the treatment chambers of the systems with three set-point temperatures (45, 50, and 55 °C) and six set-point RH (30, 35, 40, 45, 50, and 55%) until ripening. The optimal treatment combination for artificial ripening of Biser fruits was 50 °C and 50% RH. This combination provided good fruit size, color, firmness, total soluble solids (TSS), pH, and sugars content. As a result, there was a reduction in fruit weight loss and had optimum fruit ripening time. On the other hand, low temperature and RH delayed the ripening process, deteriorated fruit quality, and caused more weight loss. Although the combination of the highest temperature and RH (55 °C and 55%) reduced ripening time, the fruits have higher weight loss and negative quality. Therefore, the artificial ripening of unripe date palm Biser fruits can be achieved using 50 °C temperature and 50% RH combination. These findings can be applied in the field using solar energy systems on a commercial scale to reduce the postharvest loss of date palm fruits.

Dietary Fat and Betaine Supplements Offered to Lactating Cows Affect Dry Matter Intake, Milk Production and Body Temperature Responses to an Acute Heat Challenge.

Simple SummaryHot weather is associated with reduced milk yield of dairy cows. Supplementing the diet of lactating cows with ingredients that increase dietary energy density or that reduce internal heat production, may reduce some of the negative impacts of hot weather on milk yield. We used controlled-climate chambers to simulate a short hot-weather event and measured changes in milk yield, feed intake, and body temperature of cows fed either a fat supplement, betaine or a combination of both. Feeding cows fat resulted in improved milk production but also increased body temperature and caused a decrease in feed intake. Feeding betaine did not affect milk yield but did reduce cow body temperature at times. Contrary to our expectations, the combination of fat and betaine supplements did not result in a clear benefit in terms of milk production or body temperature. Further work is warranted to understand the interactions between dietary fat type and betaine supplements when offered to cows during periods of hot weather.Supplementing the diet of lactating cows with ingredients that increase energy density, or reduce internal heat production, may reduce some of the negative impacts of hot weather on milk yield. Thirty-two dairy cows were assigned either: (1) basal diet only, (2) basal diet plus canola oil, (3) basal diet plus betaine, or (4) basal diet plus canola oil and betaine. The basal diet was lucerne hay, pasture silage, and grain. Cows were exposed to a four-day heat challenge (temperature-humidity index 74 to 84) in controlled-environment chambers. Canola oil supplementation increased milk production (22.0 vs. 18.7 kg/d) across all periods of our experiment and increased body temperature (39.6 vs. 39.0 °C) during the heat challenge. Betaine supplementation reduced maximum body temperature during the pre-challenge period (39.2 vs. 39.6 °C) but not during the heat challenge (40.3 °C). Cows fed canola oil had greater declines in dry matter intake (5.4 vs 2.7 kg DM) and energy corrected milk (1.3 vs. 1.0 kg) from the pre-challenge to the heat challenge than other cows. Contrary to our expectations, the combination of fat and betaine supplements did not result in a clear benefit in terms of milk production or body temperature. Further work is warranted to understand the interactions between diet and hot weather.

Detection of Gas-Phase Cannabinoids

Recent changes in the legal status of cannabis augmented by a rapidly evolving social acceptance towards its consumption, highlight the immediate need for a reliable, non-invasive, point-of-use detection method for cannabis intoxication. Marijuana intoxication reduces motor coordination, slows reaction time, and impairs peripheral vision, concentration, and decision making. The rise in access and consumption of marijuana is anticipated to lead to an increase in drivers and workers impaired from its effects. Current tests for marijuana consumption are invasive (rely on blood/urine), logistically challenging (require weeks to analyze), and can only conclusively confirm use within the past month (not real-time detection). In the absence of a portable, non-invasive analytical tool to quantify marijuana intoxication, real-time THC sobriety tests rely heavily on subjective techniques that are prone to human error and/or bias. Consequently, these methods are inadequate for law enforcement, who need who need to quickly and accurately determine an individual’s state of impairment, and employers, who forbid “working under the influence”, but would allow responsible “off-duty” cannabis consumption to go unpenalized, so long as it does not affect job performance.Although there is no federal legislative consensus on the definition of marijuana intoxication, it is known that Δ9-Tetrahydrocannabinol (THC), the principle psychotropic in marijuana, has an approximate 3-hour detection window in the body that roughly correlates with symptoms of peak cannabis impairment. A small, but detectable, concentration of THC remains in equilibrium in the lungs during this 3-hour window, allowing the use of breath to be leveraged as a non-invasive method to determine recent cannabis consumption. After 3 hours, cannabinoid metabolites are rapidly diminished from the blood and lungs and absorbed into fatty tissue and the brain, reducing the efficacy of breath for use in non-invasive detection methods. While the low concentration of cannabinoids in breath ( µg/L – pg/L ) complicates detection, and there is ongoing debate as to how chronic marijuana use, gender, and body type affect baseline THC levels, there is a growing consensus that a breathalyzer will ultimately provide the best solution for a non-invasive, point-of-use detector for cannabis intoxication.Seacoast Science, Inc. is co-developing a hand-held marijuana breathalyzer in collaboration with Professors Nathaniel Lynd and Feng Zhang of UT Austin. This device will allow for the real-time, point-of-use detection and quantification of cannabinoids measured in the gas-phase. The underlying detection technology is based on the use of smart, biomimetic polymers with enhanced cannabinoid affinity measured by Micro-Electro-Mechanical Systems (MEMS) transducers (ie. chemicapacitors and chemiresistors). We will present results confirming reliable detection of a panel of gas-phase cannabinoids measured using this system in a controlled environmental chamber. The use of chemometric analysis to identify selected cannabinoids vs. common interferents will also be discussed. This technology allows a roadmap for the non-invasive analytical detection of cannabinoids in breath, which serve as biomarkers for marijuana intoxication.

Ammonia Generation System for Poultry Health Research Using Arduino.

An ammonia gas (NH3) generator was developed to maintain a set concentration of ammonia gas in a controlled environment chamber to study poultry physiological responses to sustained elevated levels of ammonia gas. The goal was to maintain 50 parts per million (ppm) of ammonia gas in a 3.7 m × 4.3 m × 2.4 m (12 ft × 14 ft × 8 ft) controlled environment chamber. The chamber had a 1.5 m3/s (3000 cfm) recirculation system that regulated indoor temperature and humidity levels and a 0.06 m3/s (130 cfm) exhaust fan that exchanged indoor air for fresh outdoor air. The ammonia generator was fabricated by coupling ultrasonic humidifiers with an Arduino-based microcontroller and a metallic oxide MQ-137 ammonia gas sensor. Preliminary evaluation under steady conditions showed the average MQ-137 gas sensor accuracy was within 1.4% of the 65.4 ppm concentration measured using a highly accurate infrared gas analyzer. Further evaluation was performed for a setpoint concentration of 50 ppm where ammonia generator reservoirs were filled with 2% or 10% ammonia liquid. For the system tested, it was found that two generators operating at the same time filled with 3.8 L (1.0 gallon) of 2% ammonia cleaning liquid each (7.6 L or 2.0 gallons total) could maintain a gas level of 49.45 ± 0.79 ppm in the chamber air for a duration of 30 h before refilling was required. One generator filled with 3.8 L of 10% ammonia cleaning liquid could maintain 51.24 ± 1.53 ppm for 195 h. Two ammonia generators were deployed for a six-week animal health experiment in two separate controlled environment chambers. The two ammonia generators maintained an average ammonia concentration of 46.42 ± 3.81 ppm and 45.63 ± 4.95 ppm for the duration of the experiment.

Protective Effects of Salicylic Acid and Calcium Chloride on Sage Plants (Salvia officinalis L. and Salviaelegans Vahl) under High-Temperature Stress.

High-temperature stress is a major risk to fresh-market Salvia production, and heat intolerance is a major constraint in sage cultivation, particularly during the hot summer season. Previously, we investigated heat tolerance in five common-market cultivars of sage plants using leaf relative injury (RI) values and found that S. elegans Vahl (SE) and S. officinalis L. (SO) were the most and least heat-tolerant species, respectively. The exogenous applications of salicylic acid (SA) and calcium chloride (CaCl2) to alleviate heat stress in various species have been extensively studied, but reports of the effects of SA and CaCl2 treatments on the heat tolerance of sage plants are scarce. The objective of this study was to investigate how SA and CaCl2 affect the physiology and morphology of SE and SO plants under high-temperature conditions. Potted plants were pretreated with SA (0, 100, 200, 400, and 800 μM) and CaCl2 (0, 5, 10, and 15 mM), alone and combined, exposed to 55 °C and 80% humidity for 30 min, then placed in an environment-controlled chamber at 30 °C for three days and evaluated for changes in phenotypic appearance, RI, spectral reflectance, and chlorophyll fluorescence indices at different time intervals. Plants watered without chemical solutions were used as controls. Our results show that the growth of SO plants pretreated with SA and CaCl2 was more robust, compared with control plants, which were considerably affected by heat stress, resulting in brown, withered leaves and defoliation. The effects of the combined applications of SA (100 μM) and CaCl2 (5 mM) to SO plants were superior to control plants in increasing values of soil-plant analysis development (SPAD), normalized difference vegetation index (NDVI), and the maximal quantum yield of photosystemII photochemistry (Fv/Fm), while reducing RI%. Furthermore, SO plants exhibited higher SPAD and Fv/Fm values and lower RI% than SE plants in combined treatments at all time intervals after heat stress, implying that different genotypes displayed variations in their SPAD, Fv/Fm, and RI%. Thus, a combined treatment of 100 μM of SA and 5 mM of CaCl2 is effective and beneficial to plant appearance and ability to ameliorate heat stress. These indices can be used as indicators to characterize the physiology of these plants and applied on a commercial scale for informing the development of rapid and precise management practices on bedded sage plants grown in plant factories to achieve maximum market benefit.

Rice mutants with tolerance to multiple abiotic stresses show high constitutive abundance of stress-related transcripts and proteins

Mutation breeding has a long track record in the development of crop cultivars with improved tolerance to abiotic stresses such as heat, salinity and drought. Oryza sativa L. cv IR64 is a very popular high yielding rice, but susceptible to major abiotic stresses, such as low and high temperatures, salinity and drought. We subjected IR64 to gamma irradiation and generated a mutant population (M3) with ~2,000 families. These were screened at the seedling stage for tolerance to high-temperature stress using hydroponics and controlled-environment chambers, resulting in the identification of three mutant lines showing a robust seedling phenotype. Under heat stress, higher CO2 assimilation (10-30%), higher spikelet fertility (40-45%) and higher antioxidant activity (15-20% catalase activity) confirmed superiority of the selected mutant lines over wild type plants at seedling and flowering stages. Upon exposure to salinity and drought stress, the three selected lines also exhibited better tolerance than wild type in terms of higher CO2 assimilation, stomatal conductance, transpiration and chlorophyll fluorescence. Transcript and protein abundance analyses confirmed higher constitutive levels of heat shock proteins and antioxidant enzymes in the mutant lines relative to wild type. Tolerance to multiple abiotic stresses was reflected in higher (25-30%) grain yield than wild type. It is anticipated that the mutant lines identified will be useful for developing new improved cultivars for dry and saline areas and may be exploited to dissect the molecular basis of multiple stress tolerance in crop plants

Thermal Comfort and Performance Evaluation of High-End Versus Popular Dupe Athleticwear Leggings

Activewear clothing consumption has significantly taken hold of the apparel industry, shifting the way consumers dress day to day. During the COVID-19 pandemic, work at home orders and pivoting business agendas prompted consumers to purchase comfortable garments that make them feel active and on-the-move. More time at home has resulted in consumers’ researching and comparing products to find the best overall value of their purchases. This research evaluated the material and comfort performance of higher price versus lower price point leggings (knits). Based on consumer research, four pairs of leggings were selected by first determining the higher price point leggings and their consumer preferred dupes. The laboratory evaluations for each pair of leggings included fabric weight, thickness, pilling resistance, opacity, vertical wicking, and air permeability. A dynamic sweating thermal manikin was utilized to assess the physiological responses (primarily skin temperature and comfort sensation) of each pair of leggings, tested on a 35 zone ANDI thermal manikin in a controlled environmental chamber. Although the Brand A leggings were the most expensive, they could be considered the most valuable as they significantly outperformed all leggings in this study. Brand D dupe leggings may be considered a better value than brand C as they were half the price and had a similar material performance.

Some evidence of a time-varying thermal perception

Recent research suggests that a time-varying indoor thermal environment can lead to energy savings and contribute to boost buildings' energy flexibility. However, thermal comfort standardization has so far considered thermal comfort criteria as constant throughout the day. In general, very little attention has been given to the ‘ time of day' variable in the context of thermal comfort research. In this paper, we show some evidence of a time-varying thermal perception by using: (1) data from about 10,000 connected Canadian thermostats made available as part of the ‘ Donate Your Data' dataset and (2) about 22,000 samples of complete (objective + ‘ right-here-right-now' subjective) thermal comfort field data from the ASHRAE I and SCATs datasets. We observe that occupants prefer colder thermal conditions at 14:00 and progressively warmer ones in the rest of the day, indistinctively in the morning and evening. Neutral temperature differences between 08:00 and 14:00 and 14:00 and 20:00 are estimated to be of the order of 2°C. We hypothesize that the human circadian rhythm is the cause of this difference. Nevertheless, the results of this study are only based on observational data. Thermal comfort experiments in controlled environmental chambers are required to confirm these findings and to better elucidate the effects of light and circadian timing and their interaction on thermal perception.

Corneal lymphangiogenesis in dry eye disease is regulated by substance P/neurokinin-1 receptor system through controlling expression of vascular endothelial growth factor receptor 3

PurposeTo evaluate the role of substance P (SP)/neurokinin-1 receptor (NK1R) system in the regulation of pathologic corneal lymphangiogenesis in dry eye disease (DED). MethodsImmunocytochemistry, angiogenesis assay, and Western blot analysis of human dermal lymphatic endothelial cells (HDLECs) were conducted to assess the involvement of SP/NK1R system in lymphangiogenesis. DED was induced in wild-type C57BL/6 J mice using controlled-environment chamber without scopolamine. Immunohistochemistry, corneal fluorescein staining, and phenol red thread test were used to evaluate the effect of SP signaling blockade in the corneal lymphangiogenesis. The expression of lymphangiogenic factors in the corneal and conjunctival tissues of DED mouse model was quantified by real-time polymerase chain reaction. ResultsNK1R expression and pro-lymphangiogenic property of SP/NK1R system in HDLECs were confirmed by Western blot analysis and angiogenesis assay. Blockade of SP signaling with L733,060, an antagonist of NK1R, or NK1R-targeted siRNA significantly inhibited lymphangiogenesis and expression of vascular endothelial growth factor (VEGF) receptor 3 stimulated by SP in HDLECs. NK1R antagonist also suppressed pathological corneal lymphangiogenesis and ameliorated the clinical signs of dry eye in vivo. Furthermore, NK1R antagonist effectively suppressed the lymphangiogenic factors, including VEGF-C, VEGF-D, and VEGF receptor 3 in the corneal and conjunctival tissues of DED. ConclusionsSP/NK1R system promotes lymphangiogenesis in vitro and NK1R antagonism suppresses pathologic corneal lymphangiogenesis in DED in vivo.

Evaluation of foamed nickel photocatalytic filters for an air cleaner on removal of formaldehyde in the indoor environment

Foamed nickel photocatalytic filters based on zinc oxide and fitted to standard air cleaner are assessed under the same indoor air quality conditions in a real test site setting with UV light applied via a suitable lamp. Environmental parameters determined using a chamber test are input to the mass balance model and airflow analysis software (CONTAM) to simulate the change of HCHO concentration with time at the real test site. The mass balance model is validated by mean absolute percentage error (MAPE). Results of the environmental control chamber test for ZnO filters at 60 min interval show the highest removal efficiency for HCHO are under no UV light irradiation. It also shows that regardless of whether the UV lamp is on or off, the highest removal efficiency for HCHO is under high humidity and low concentration. The removal efficiency of HCHO with application of UV light is not significantly affected by low humidity and low concentration. Clean air delivery rates (CADR) of the air cleaner are consistent with HCHO removal efficiency, i.e., higher CADR brings higher removal efficiency. The results show the removal efficiency of HCHO by TiO2 photocatalytic filters is higher than that obtained with ZnO photocatalytic filters under UV light irradiation. For the real test site, the MAPEs of the simulations are 13.52 ~ 38.80% for changes of HCHO concentrations in 20 min interval with mass balance model and CONTAM. The MAPEs of HCHO for CONTAM simulations is 5.38%, which shows the CONTAM has good.

Diverse Physiological and Physical Responses among Wild, Landrace and Elite Barley Varieties Point to Novel Breeding Opportunities

Climate change from elevated [CO2] may reduce water availability to crops through changes in precipitation and higher temperatures. However, agriculture already accounts for 70% of human consumption of water. Stomata, pores in the leaf surface, mediate exchange of water and CO2 for the plant. In crops including barley, the speed of stomatal response to changing environmental conditions is as important as maximal responses and can thus affect water use efficiency. Wild barleys and landraces which predate modern elite lines offer the breeder the potential to find unexploited genetic diversity. This study aimed to characterize natural variation in stomatal anatomy and leaf physiology and to link these variations to yield. Wild, landrace and elite barleys were grown in a polytunnel and a controlled environment chamber. Physiological responses to changing environments were measured, along with stomatal anatomy and yield. The elite barley lines did not have the fastest or largest physiological responses to light nor always the highest yields. There was variation in stomatal anatomy, but no link between stomatal size and density. The evidence suggests that high photosynthetic capacity does not translate into yield, and that landraces and wild barleys have unexploited physiological responses that should interest breeders.

Growth Stage Specific Lighting Spectra Affect Photosynthetic Performance, Growth and Mineral Element Contents in Tomato

The aim of study was to evaluate if the alternation in growth stage–specific lighting spectrum would be superior for tomato growth, photosynthesis, and mineral element contents compared to constant spectrum lighting. Dwarf tomato (Solanum lycopersicum L. cv. Micro Tom) was cultivated in controlled environment chamber (23/19 °C) under light emitting diode lighting. Three lighting spectrum treatments were set, optimized for different tomato growth stages: “seedling” (S; blue (B, 447 nm), red (R, 660 nm) and far red (FR, 740 nm) light), “growth” (G; R, B and FR light, supplemented with 523 nm green) and fruiting (F; R, B, FR light supplemented with 385 nm ultraviolet A (UV-A)). The total photon flux density of 250 μmol m−2·s−1 was maintained in all treatments. Three lighting spectrums were alternated in seedling (S, G, F), biomass growth (SS, SG, GG, FF) and fruiting (SSS, SGG, GGG, GGF, FFF, SGF) stages of tomato creating growth stage-specific or constant lighting spectrum strategies. The light effects depended on tomato age, however the alternation in growth stage-specific lighting spectrum did not have a pronounced impact on dwarf tomato photosynthetic indices, growth, yield and mineral element content. The investigated parameters mainly depended on the spectrum of the latter growth stage.

Heat stress affects floral morphology, silique set and seed quality in chamber and field grown winter canola

AbstractThe impact of heat stress coinciding with reproductive stages in winter canola was studied using walk‐in controlled environment chambers and field‐based tents. Six different cultivars (46W94, Edimax CL, Mercedes, Popular, DKW44‐10 and DKW46‐15) were used in both the experiments following a split‐plot design. Under controlled environment chambers, all six cultivars were exposed to HDT (day/night; 34/15°C), HNT (23/20°C), HDNT (34/20°C) and control (23/15°C) conditions for 14 days coinciding with flowering. Under field conditions, custom built ‘heat tents’ were used to impose heat stress starting seven days after 50% of flowering till maturity. The results demonstrated that HDT and HDNT induced significant impact on floral morphology, extreme levels of floral sterility and complete yield loss with two weeks of stress exposure during flowering. However, biomass, seed weight and oil concentration at maturity were either significantly increased or unchanged which demonstrated significant post‐stress phenotypic plasticity in canola to overcome damage caused by short episode of HDT and HDNT during flowering. The long duration heat stress under field conditions recorded significant decrease in yield parameters and oil concentration in the canola cultivars. Incorporating greater post‐stress phenotypic plasticity will help develop canola as an ideal alternative crop under future climates associated with enhanced frequency of short heat stress episodes coinciding with critical reproductive stages.

Hyperlocal Variation in Soil Iron and the Rhizosphere Bacterial Community Determines Dollar Spot Development in Amenity Turfgrass.

Dollar spot, caused by the fungal pathogen Clarireedia spp., is an economically important foliar disease of amenity turfgrass in temperate climates worldwide. This disease often occurs in a highly variable manner, even on a local scale with relatively uniform environmental conditions. The objective of this study was to investigate mechanisms behind this local variation, focusing on contributions of the soil and rhizosphere microbiome. Turfgrass, rhizosphere, and bulk soil samples were collected from within a 256-m2 area of healthy turfgrass, transported to a controlled environment chamber, and inoculated with Clarireedia jacksonii Bacterial communities were profiled by targeting the 16S rRNA gene, and 16 different soil chemical properties were assessed. Despite their initial uniform appearance, the samples differentiated into highly susceptible and moderately susceptible groups following inoculation in the controlled environment chamber. The highly susceptible samples harbored a unique rhizosphere microbiome with suggestively lower relative abundance of putative antibiotic-producing bacterial taxa and higher predicted abundance of genes associated with xenobiotic biodegradation pathways. In addition, stepwise regression revealed that bulk soil iron content was the only significant soil characteristic that positively regressed with decreased dollar spot susceptibility during the peak disease development stage. These findings suggest that localized variation in soil iron induces the plant to select for a particular rhizosphere microbiome that alters the disease outcome. More broadly, further research in this area may indicate how plot-scale variability in soil properties can drive variable plant disease development through alterations in the rhizosphere microbiome.IMPORTANCE Dollar spot is the most economically important disease of amenity turfgrass, and more fungicides are applied targeting dollar spot than any other turfgrass disease. Dollar spot symptoms are small (3 to 5 cm), circular patches that develop in a highly variable manner within plot scale even under seemingly uniform conditions. The mechanism behind this variable development is unknown. This study observed that differences in dollar spot development over a 256-m2 area were associated with differences in bulk soil iron concentration and correlated with a particular rhizosphere microbiome. These findings provide interesting avenues for future research to further characterize the mechanisms behind the highly variable development of dollar spot, which may inform innovative control strategies. Additionally, these results suggest that small changes in soil properties can alter plant activity and hence the plant-associated microbial community, which has important implications for a broad array of agricultural and horticultural plant pathosystems.

Modulating Vapor Pressure Deficit in the Plant Micro-Environment May Enhance the Bioactive Value of Lettuce

Growing demand for horticultural products of accentuated sensory, nutritional, and functional quality traits has been driven by the turn observed in affluent societies toward a healthy and sustainable lifestyle relying principally on plant-based food. Growing plants under protected cultivation facilitates more precise and efficient modulation of the plant microenvironment, which is essential for improving vegetable quality. Among the environmental parameters that have been researched for optimization over the past, air relative humidity has always been in the background and it is still unclear if and how it can be modulated to improve plants’ quality. In this respect, two differentially pigmented (green and red) Salanova® cultivars (Lactuca sativa L. var. capitata) were grown under two different Vapor Pressure Deficits (VPDs; 0.69 and 1.76 kPa) in a controlled environment chamber in order to appraise possible changes in mineral and phytochemical composition and in antioxidant capacity. Growth and morpho-physiological parameters were also analyzed to better understand lettuce development and acclimation mechanisms under these two VPD regimes. Results showed that even though Salanova plants grown at low VPD (0.69 kPa) increased their biomass, area, number of leaves and enhanced Fv/Fm ratio, plants at high VPD increased the levels of phytochemicals, especially in the red cultivar. Based on these results, we have discussed the role of high VPD facilitated by controlled environment agriculture as a mild stress aimed to enhance the quality of leafy greens.