Controlled Environment Chambers Research Articles

Effects of end-of-day far-red light and relative humidity on flowering and stem elongation of petunia (Petunia × hybrida) seedlings

Far-red light at the end of the day (EOD-FR) can promote the flowering of long-day plants. However, it can cause excessive stem elongation that reduces the quality of transplants. Therefore, flowering and stem elongation must be balanced when EOD-FR is used in bedding-plant production. Here, we examined the interactive role of relative humidity (RH) to suppress excessive elongation caused by EOD-FR and the combined effects of EOD-FR and RH on flowering and stem elongation of petunia (Petunia × hybrida) seedlings. We grew seedlings for 28 days in controlled-environment chambers after two true leaves had expanded, with or without EOD-FR, at 40 % or 80 % RH. We found a significant EOD-FR × RH interaction in stem length, with a smaller increase in stem length due to EOD-FR at lower RH. Flower development, which was evaluated using the node position at first flowering, was promoted by EOD-FR. However, low RH suppressed flower development both with and without EOD-FR, thereby counteracting the promotion of flower development by EOD-FR. Thus, EOD-FR treatment at low RH could not prevent excessive stem elongation while promoting flowering. Clarifying the eco-physiological reasons why low RH counteracts the FR-induced promotion of flowering associated with the shade-avoidance response may be necessary to improve flowering control with bedding plant transplants under a controlled environment.

Effects of temperature and relative humidity on behavior and physiological indices in goats

High temperature and relative humidity (RH) affect the production and health of livestock. This study aimed to investigate the change rule of behavior and internal physiological status of goats under heat stress and determine the relationship between these factors. Eight 18-month-old female goats (non-pregnant or non-lactating) were randomly assigned to two environmental control chambers (labeled A and B; n = 4 per in each batch). Four temperatures (26 °C, 30 °C, 34 °C, and 38 °C) and four RH levels (35%, 5 0%, 65%, and 80%) were applied according to a 4 × 4 experimental design to establish a normal control (23 °C, 50%) and the experimental treatments. The duration of each treatment was five days. The behaviors of the goats were monitored in the first two days, the physiological indices were measured, and serum was collected within 3–5 d. The respiratory rate and HSP70 mRNA expression significantly increased at 74.8 < temperature-humidity index (THI) < 76.51; T3 significantly decreased at 80.62 < THI < 82.92; and the behaviors related to metabolism also significantly decreased at 85.24 < THI < 88.74 (including heart rate and rumination). However, the behaviors related to vapor cooling (including respiratory rate, water intake and urination) showed an opposite trend at this stage. In addition, heat stress disrupted the balance of interleukin-2 (IL-2)/interleukin-4 (IL-4). These findings provide a reference for designing suitable environments for goat breeding.

Protecting Tear-Film Stability under Adverse Environmental Conditions Using a Mucomimetic with a Non-Newtonian Viscosity Agent.

Background and Objectives: Tamarind-seed polysaccharide (TSP) and hyaluronic acid (HA) have mucoadhesive properties that improve drug absorption and delay in drug elimination from the ocular surface. We aimed to evaluate TSP/HA-containing formulation for its efficiency in dry-eye symptoms induced by adverse environments and the interaction between mucomimic polymer and tear-film parameters. Materials and Methods: The participants were exposed to 5% relative humidity (RH) in a Controlled Environment Chamber (CEC) under constant room temperature (21 °C). Tear-film parameters were assessed at 40% RH and 5% RH. Rohto Dry Eye Relief drops were used in the two treatment modalities, protection (drops instilled before exposure to the dry environment) and relief (drops instilled after exposure to the dry environment). The HIRCAL grid, Servomed EP3 Evaporimeter, and Keeler's TearScope-Plus were used to screen for non-invasive tear break-up time (NITBUT), tear evaporation rate, and lipid-layer thickness (LLT) using protection and relief treatment methodology. Results: LLT was found to be significantly thinner at 5% RH compared with at 40% RH (p = 0.007). The median LLT dropped from 50-70 nm (grade 3) at 40% RH to 10-50 nm (grade 2) at 5% RH. TSP/HA eye drops significantly augment LLT in both treatment modalities, protection (p = 0.01) and relief (p = 0.004) at 5% RH. The mean evaporation rate doubled from 40.93 at 40% RH to 82.42 g/m2/h after exposure to 5% RH. In protection mode, the TSP/HA allowed the average evaporation rate to be much lower than when no TSP/HA was used at 5% RH (p < 0.008). No alteration in evaporation rate was recorded when the TSP/HA drop was used after exposure (relief). The mean NITBUT was reduced from 13 s in normal conditions to 6 s in the dry environment. Instillation of TSP/HA eye drops resulted in significant improvement (p = 0.006) in tear stability, where the NITBUT increased to 8 s in both protection (before exposure) and relief (after exposure) (p = 0.001). Although improved, these values were still significantly lower than NITBUT observed at 40% RH. Conclusions: Significant protection of tear-film parameters was recorded post instillation of TSP/HA eye drop under a desiccating environment. Both treatment methods (protection and relief) were shown to be effective. The presence of TSP/HA enhances the effectiveness of teardrops in protecting the tear-film parameters when exposed to adverse environments.

Investigating the influence of elevated temperature on nutritional and yield characteristics of mung bean (Vigna radiata L.) genotypes during seed filling in a controlled environment.

Rising temperatures impact different developmental stages of summer crops like mung bean, particularly during the crucial seed-filling stage. This study focused on two mung bean genotypes, categorized as heat-tolerant [HT] or heat-sensitive [HS]. These genotypes were grown in pots in an outdoor natural environment (average day/night temperature 36°C/24.3°C) until the onset of podding (40 days after sowing) and subsequently relocated to controlled-environment walk-in growth chambers for exposure to heat stress (42°C/30°C) or control conditions (35°C/25°C) until maturity. For all measured attributes, heat stress had a more pronounced effect on the HS genotype than on the HT genotype. Heat-stressed plants exhibited severe leaf damage, including membrane damage, reduced chlorophyll content, diminished chlorophyll fluorescence, and decreased leaf water content. Heat stress impeded the seed-filling rate and duration, decreasing starch, protein, fat, and mineral contents, with a notable decline in storage proteins. Heat stress disrupted the activities of several seed enzymes, inhibiting starch and sucrose accumulation and consequently decreasing individual seed weights and seed weight plant-1. This study revealed that heat stress during seed filling severely impaired mung bean seed yield and nutritional quality due to its impact on various stress-related traits in leaves and enzyme activities in seeds. Moreover, this research identified potential mechanisms related to heat tolerance in genotypes with contrasting heat sensitivity.

Assessing a thermoelectric radiative cooling partition as a personalised comfort system using empirical experiments enhanced by digital shadow visualisation

The thermoelectric cooling partition–named Thecla–is a novel hardware setup for individual cooling through radiation exchange with the user's body. In this research, the results of experiments on Thecla as a personalised comfort system (PCS) are investigated to evaluate the cooling effect of Thecla and its impact on thermal comfort. The experiments took place in a controlled-environment climate chamber using a thermal manikin. Furthermore, visualisation as a virtual reality technology was integrated in a digital shadow using the sensors' readings to enhance visualising the thermal impact of Thecla.Comparing the measurements at 28 °C and 30 °C; the higher the temperature, the better the effect of Thecla is on the body parts of the manikin. The results of Thecla as a cooling PCS in 30 °C presented a reduction of local skin temperature by up to 0.5 K. In addition, a reduction was observed in local thermal sensation of 0.12–0.38 points of the 9-point scale; as well as an increase in the body heat dissipation by about 10%. The digital shadow was built on the data of empirical measurements to resemble an interface to monitor thermal changes to improve users' perception of the thermal variations in the ambiance of Thecla. Thus, an easy-to-understand observation of the results allows further control of Thecla based on the visualisation and consequently enhances thermal comfort. This study enables further future investigation aided by visualisation of the thermal effect of PCS on human subjects to analyse individual thermal perceptions and preferences.

Effect of Hardwood Dust and Ammonia Gas on the Respiratory Integrity of Broiler Chickens.

Dust and ammonia gas (NH3) are two of the most abundant pollutants suspended in the air of poultry houses. Chronic inhalation of poultry dust and NH3 causes damage to the airways and reduces performance in broilers. Poultry dust is a mixture of organic and inorganic matter from feed, bedding material, manure, feathers, skin debris, and microorganisms. Thus, the composition and concentration of poultry dust vary among farms. This study proposes a model to assess the individual effect of a defined fraction of poultry dust derived from bedding material (wood dust) and its effects, alone or combined with NH3, on the performance and respiratory integrity of broilers. Ninety-six, 1-day-old broilers were randomly divided into groups of 24 and placed into four controlled environment chambers to continuously receive one of four treatments: 1) negative control; 2) exposure to airborne red oak wood dust at a concentration of 7.5 × 106 particles/m3 (particulate matter5.0); 3) exposure to 50 parts per million (ppm) of NH3; and 4) exposure to airborne red oak wood dust and 50 ppm of NH3. On day 43, all birds were weighed and euthanized. Performance data were recorded. Tissue samples were collected from six birds per treatment. Histologic evaluations of the nasal turbinates, trachea, and lungs were conducted. Histologic lesion scores (0 to 3) were assigned, and tracheal mucosal thickness was measured. No significant differences among treatments were found in body weight (P = 0.066), tracheal mucosal thickness (P = 0.593), or tracheal lesion score (P = 0.07). The average nasal turbinate lesion scores were higher in the wood and wood + ammonia treatments compared with the control (P = 0.015). The lung lesion scores were higher (P = 0.004) in all treatment groups compared with the control. In conclusion, chronic exposure to red oak wood dust, alone or in combination with NH3, induced important inflammatory damage to portions of the respiratory system of broilers; however, no significant effects on performance were observed.

Improved chilling tolerance in glasshouse-grown potted sweet basil by end-of-production, short-duration supplementary far red light.

Sweet basil is a popular culinary herb used in many cuisines around the world and is widely grown commercially for retail as a live potted plant. However, basil is easily damaged by temperatures below 12 °C meaning plants must be transported from the grower to the retailer in a warm transport chain, adding considerable commercial cost in temperate countries. Improvement of chilling tolerance has been demonstrated in post-harvest crops such as tomato fruits and, indeed, fresh cut basil, by manipulation of the red:far red ratio of light provided to plants throughout the photoperiod and for a significant duration of the growing process in controlled environment chambers. We tested the effectiveness of periodic short-duration end-of-production supplementary far red light treatments designed for use with basil plants grown in a large scale commercial glasshouse for the live potted basil market. Four days of periodic, midday supplementary far red light given at end of production induced robust tolerance to 24 h of 4 °C cold treatment, resulting in greatly reduced visual damage, and reduced physiological markers of chilling injury including electrolyte leakage and reactive oxygen species accumulation. Antioxidant levels were also maintained at higher levels in live potted basil following this cold treatment. RNAseq-based analysis of gene expression changes associated with this response pointed to increased conversion of starch to soluble raffinose family oligosaccharide sugars; increased biosynthesis of anthocyanins and selected amino acids; inactivation of gibberellin signaling; and reduced expression of fatty acid desaturases, all previously associated with increased chilling tolerance in plants. Our findings offer an efficient, non-invasive approach to induce chilling tolerance in potted basil which is suitable for application in a large-scale commercial glasshouse.

Tear film changes in symptomatic versus asymptomatic video display terminal users following computer challenge test

PurposeTo assess the real-time changes in the tear film and ocular surface of symptomatic video display terminal (VDT) versus asymptomatic users. MethodsA total of 35 symptomatic (29 ± 5.6 years; Group 1, mild dry eye disease) and 35 asymptomatic (24.1 ± 4.6 years; Group 2) VDT users with a mean OSDI of 28 ± 11 and 0.86 ± 2.1, respectively, had tear film examination (Oculus Keratograph 5 M and Tearlab Osmolarity System) at baseline and after 1 h of watching a movie on the laptop inside a controlled environment chamber along with blink rate calculation. ResultsThe mean VDT use was 11.4 ± 3.2 h/day in Group 1 and 2.3 ± 2.3 h/day in Group 2. In Group 1, the mean pre- and post-VDT task values for NIBUT and bulbar congestion were 10.7 ± 3.7s and 6.7 ± 3.1s (P = 0.007), and 0.8 ± 0.4 and 1.1 ± 0.5 (P = 0.01), respectively. There were no significant changes in tear meniscus height (P = 0.77), Schirmer I (P =0.14), corneal staining score (P = 1.0), and tear osmolarity (P > 0.05). Group 2 showed insignificant change in all parameters. Only 16.2% individuals in Group 1 met modified TFOS-DEWS II diagnostic criteria at baseline that increased to 67.6% following VDT task. The blink rate reduced significantly during the last 15 min (6.8 ± 3.4 vs. 9.3 ± 4.5; P = 0.006) compared to the first 15 min of the task in Group 1, whereas no significant change occurred in Group 2. ConclusionTear film instability and increased bulbar congestion are observed in symptomatic VDT users after computer work despite baseline stable tear film. The changes are significantly altered in symptomatic VDT users compared to asymptomatic users.

Evaluation of Therapeutic Capability of Emustil Drops against Tear Film Complications under Dry Environmental Conditions in Healthy Individuals.

Background and Objectives: Dry eye disease (DED) is a multifactorial ailment of the tears and ocular surface. The purpose of this study was to assess the tear film physiology under controlled dry environmental conditions and compare the efficacy of oil-in-water emulsion drops on tear film parameters in protection and relief treatment modalities under low-humidity conditions. Emustil eye drops were used after exposure to a low-humidity environment in the relief method, whereas, in the protection method, the drops were applied before exposure to low humidity. Materials and Methods: 12 normal male subjects (mean age 34.0 ± 7.0 years) were exposed to ultra-dry environmental conditions. A number of tear film measurements were carried out under desiccating environmental conditions in a controlled environment chamber (CEC), where the chamber temperature sat at 21 °C with a relative humidity (RH) of 5%. Keeler's TearScope Plus and an HIRCAL grid were used to assess the tear break-up time and lipid layer thickness (LLT), and the evaporation rate was evaluated using a Servomed EP3 Evaporimeter. Results: LLT measurements showed that the dry environment affected LLT significantly (p = 0.031). The median grade of LLT dropped from grade 3 (50-70 nm) at 40% RH to grade 2 (13-50 nm) at 5% RH. A significant increase in LLT was seen after both modes of treatment, with a median LLT grade of 3 when the Emustil was used for both protection (p = 0.004) and relief (p = 0.016). The mean tear evaporation rate in normal environmental conditions (40%) was 40.46 ± 11.80 g/m2/h (0.11 µL/min) and increased sharply to 83.77 ± 20.37 g/m2/h (0.25 µL/min) after exposure to the dry environment. A minimal decrease in tear film evaporation rate was seen in relief; however, statistical tests showed that the decrease in tear film evaporation rate was not significant. Mean NITBUT dropped from 13.6 s at 40% RH to 6.6 s at 5% RH (p = 0.002). All NITBUT measurements at 5% RH (with or without the instillation of Emustil) were significantly lower than those at 40%. The instillation of Emustil at 5% RH resulted in a significant improvement in NITBUT for protection (p = 0.016) but this was not the case for relief (p = 0.0.56). Conclusions: A control environmental chamber (CEC) enables the analysis of tear film parameters comparable to those found in dry eye patients. This enables us to examine the capability of oil in emulsion drops to manage tear film disruption in healthy individuals. This study suggests that using Emustil oil-in-water emulsion before exposure to a dry environment should be advocated for people who work in dry environments.

Research on thermal comfort of obese and overweight people during indoor running exercise

Regular and adequate physical exercise plays a pivotal role in enhancing physical fitness, mitigating the occurrence of obesity, and upholding body weight. The comfort of individuals engaging in exercise is significantly impacted by various environmental factors within sports fields, including ambient temperature, humidity, air velocity, and mean radiant temperature. To investigate the influence of ambient temperature, relative humidity, and body mass index (BMI) on the comfort levels of individuals with high body fat during exercise, treadmill running experiments were conducted within controlled environmental chambers. Furthermore, the subjects’ subjective sensations and physiological indexes were recorded. The results implied that subjects exhibited a broader range of acceptable thermal sensations during exercise compared to rest periods. Moreover, individuals with a higher BMI displayed heightened sensitivity to elevated temperatures and a greater propensity for perceiving sensations of heat, resulting in a narrower range of acceptable exercise conditions. Additionally, the findings highlighted that air temperature exerted a more pronounced impact on comfort levels than humidity. For indoor running exercises, it was advisable to maintain ambient temperatures within the ranges of 15.1°C–24.3 °C and 16.1°C–27.8 °C for obese and overweight individuals, respectively. Furthermore, it was recommended to maintain a relative humidity level between 50% and 80% in the exercise environment.

Impact of Phytase Supplementation on Meat Quality of Heat-Stressed Broilers.

Heat stress (HS) is one of the most challenging stressors to poultry production sustainability. The adverse effects of HS range from feed intake and growth depression to alteration of meat quality and safety. As phytase supplementation is known to improve nutrient utilization and consequently growth, we undertook the present study to evaluate the effects of dietary phytase on growth and meat quality in heat-stressed broilers. A total of 720 day-old hatch Cobb 500 chicks were assigned to 24 pens within controlled environmental chambers and fed three diets: Negative Control (NC), Positive Control (PC), and NC diet supplemented with 2000 phytase units (FTU)/kg) of quantum blue (QB). On day 29, birds were exposed to two environmental conditions: thermoneutral (TN, 25 °C) or cyclic heat stress (HS, 35 °C, 8 h/d from 9 a.m. to 5 p.m.) in a 3 × 2 factorial design. Feed intake (FI), water consumption (WI), body weight (BW), and mortality were recorded. On day 42, birds were processed, carcass parts were weighed, and meat quality was assessed. Breast tissues were collected for determining the expression of target genes by real-time quantitative PCR using the 2-ΔΔCt method. HS significantly increased core body temperature, reduced feed intake and BW, increased water intake (WI), elevated blood parameters (pH, SO2, and iCa), and decreased blood pCO2. HS reduced the incidence of woody breast (WB) and white striping (WS), significantly decreased drip loss, and increased both 4- and 24-h postmortem pH. Instrumental L* and b* values were reduced (p < 0.05) by the environmental temperature at both 4- and 24-h postmortem. QB supplementation reduced birds' core body temperature induced by HS and improved the FCR and water conversion ratio (WCR) by 1- and 0.5-point, respectively, compared to PC under HS. QB increased blood SO2 and reduced the severity of WB and WS under TN conditions, but it increased it under an HS environment. The abovementioned effects were probably mediated through the modulation of monocarboxylate transporter 1, heat shock protein 70, mitogen-activated protein kinase, and/or glutathione peroxidase 1 gene expression, however, further mechanistic studies are warranted. In summary, QB supplementation improved growth performance and reduced muscle myopathy incidence under TN conditions. Under HS conditions, however, QB improved growth performance but increased the incidence of muscle myopathies. Therefore, further QB titration studies are needed.

Aerosol absorption measurement by a Shack-Hartmann wavefront sensor.

Researchers at the U.S. Army Space and Missile Defense Command have developed a method for quantifying high energy near-infrared (NIR) laser heating of air resulting from laser absorption of suspended dry aerosols in a controlled environmental chamber. The measurements were accomplished using an ISO standard test dust and NIR high energy laser using a Shack-Hartmann wavefront sensor. This paper presents the methodology of the measurement as well as the quantitative reconstruction of the air temperature profile, absorption efficiency, and imaginary refractive index of the aerosol. The resulting measurement of the aerosol imaginary index of refraction was significantly lower than values typically found in the literature from measurements using low power techniques. These findings are in general agreement with other recently published works that have found that previously published values of mineral dust aerosols could be significantly overestimated.

Cuticular hydrocarbons as weathering biomarkers of empty puparia of the forensically important blowfly Calliphora vicina Robineau-Desvoidy, 1830 (Diptera: Calliphoridae) in soil v/s under room conditions

Forensic entomology uses the age of insects, such as blow flies, to determine a minimum post-mortem interval (PMImin). Recent research has focused on using the analysis of specific cuticular hydrocarbons (CHCs) in adult insects and their empty puparia to estimate their age, as it has been shown that their profile changes are consistent with age. The current work is based on the weathering of five CHCs from empty puparia of Calliphora vicina that were stored in soil (field/outdoor) and non-soil (room/indoor conditions) based pupariation media for a total of six months. The experiment was conducted in a controlled environment chamber at a constant temperature of 25 ± 2 °C under constant darkness. Gas chromatography-mass spectrometry (GC-MS) was used to analyze the cuticular hydrocarbons after they were extracted in n-Hexane. n-Pentacosane, n-Hexacosane, n-Heptacosane, n-Octacosane, and n-Nonacosane were the five CHCs investigated. Results showed that CHCs weathered more quickly in the soil than in the non-soil environment. It was also found that the abundance of Heptacosane increased in the samples during the fifth month when stored in a non-soil medium, while the abundances of all five CHCs were not detected after eight weeks onwards in soil pupation medium.

Evaluation of different treatment modalities on the efficacy of hydroxypropyl Guar (HP-Guar) formulation on tear film stability (TFS) in subjects exposed to adverse environmental conditions

The study aimed to assess the efficacy of hydroxypropyl guar (HP) formulation (Systane) to protect tear film parameters under desiccating environment using protection and relief treatment modalities. The subjects were exposed to adverse environmental conditions using a Controlled Environment Chamber (CEC) where the relative humidity (RH) was 5% and the ambient temperature was 21 °C and screened for Tear break-up time (TBUT), Tear film evaporation rate (TFER) and lipid layer thickness (LLT) using the HIRCAL grid, Servomed EP3 Evaporimeter and Keeler’s TearScope-Plus respectively. Significant improvement in LLT was noticed in the protection modality. The mean tear film evaporation rate doubled after exposure to the humidity of 5% to a value of 105.37 g/m2/h (0.29 µl/min). All subjects displayed a significant reduction in non-invasive tear break-up time (NITBUT) with a mean NITBUT of 7.7 s after exposure to a desiccating environment for 15 min. A significant increase in NITBUT after the instillation of the drops was recorded in both methods. The results obtained from this study showed that a solution containing HP-Guar significantly improves tear film parameters under a desiccating environment. Apart from the tear evaporation rate, all tear parameters showed improvement after the use of HP-Guar eye drops. It is evident that tear film parameters respond differently to the management modalities and using CEC has the potential to provide researchers with a readily available method to evaluate the efficiency of tear supplementation.

Temperature driven variations in VOC emissions from plastic products and their fate indoors: A chamber experiment and modelling study

Plastic products are ubiquitous in our homes, but we know very little about emissions from these products and their subsequent impact on indoor air quality. This is the first study to systematically determine temperature-dependent emissions of volatile organic compounds from commonly used plastic consumer products found in the home. The plastic types included high-density polyethylene (HDPE), polypropylene (PP), polyethylene terephthalate (PET), polystyrene (PS) and polyester rubber. Plastic samples were exposed to increasing temperatures (between 18 and 28 °C) in controlled environmental chambers, connected to a proton-transfer-reaction time-of-flight mass-spectrometer (PTR-ToF-MS), where real-time emissions were detected. Average emission rates were determined and used to initialise an indoor air chemistry model (INCHEM-Py) at the highest and lowest experimental temperatures, to explore the impact these product emissions have on the indoor air chemistry. The PS tubing plastic proved to be the highest emitting polymer per surface area. Almost all selected VOC emissions were found to have a linear relationship with temperature. Upon observing the impacts of primary VOC emissions from plastics in modelled simulations, the hydroxyl radical concentration decreased by an average of 1.6 and 10 % relative to the baseline (with no plastics included) at 18 °C and 28 °C respectively. On the other hand, formaldehyde concentrations increased by 29 and 31.6 % relative to the baseline conditions at 18 °C and 28 °C respectively. The presence of plastic products indoors, therefore, has the potential to impact the indoor air quality.

Experimental study of the effects of temperature and humidity on the wear and damage behavior of U71Mn rail steel

Wheel-rail interfaces operating in open systems are constantly affected by environmental factors, such as water, relative humidity, temperature, leaves, and sand. In this study, a twin-disc rolling-sliding friction and wear test device with a controlled environmental chamber was used to conduct experiments to study the influence of high temperature and humidity on the wear and damage behavior of U71Mn rail steel. The results showed that surface oxidation of rails increased with increasing temperature and humidity. The surface oxides and very humid air provided lubrication that could reduce wear. With increasing temperature and humidity, the trend of the friction coefficient of the rail samples was basically consistent with that of the plastic deformation layer. The wear of rail samples first decreased and then increased with increasing humidity. However, with increasing temperature, the wear of the rail samples first increased and then decreased. With increasing temperature and humidity, the crack length on the rail surface gradually increased and extended to the center of the material, which made the competition between wear and rolling contact fatigue more intense. When the wear was less than rolling fatigue, rail surfaces underwent severe cracking and peeling, which resulted in the loss of a large amount of surface material.

Elevated CO2 Priming as a Sustainable Approach to Increasing Rice Tiller Number and Yield Potential

Tillering and yield are linked in rice, with significant efforts being invested to understand the genetic basis of this phenomenon. However, in addition to genetic factors, tillering is also influenced by the environment. Exploiting experiments in which seedlings were first grown in elevated CO2 (eCO2) before transfer and further growth under ambient CO2 (aCO2) levels, we found that even moderate exposure times to eCO2 were sufficient to induce tillering in seedlings, which was maintained in plants grown to maturity plants in controlled environment chambers. We then explored whether brief exposure to eCO2 (eCO2 priming) could be implemented to regulate tiller number and yield in the field. We designed a cost-effective growth system, using yeast to increase the CO2 level for the first 24 days of growth, and grew these seedlings to maturity in semi-field conditions in Malaysia. The increased growth caused by eCO2 priming translated into larger mature plants with increased tillering, panicle number, and improved grain filling and 1000 grain weight. In order to make the process more appealing to conventional rice farmers, we then developed a system in which fungal mycelium was used to generate the eCO2 via respiration of sugars derived by growing the fungus on lignocellulosic waste. Not only does this provide a sustainable source of CO2, it also has the added financial benefit to farmers of generating economically valuable oyster mushrooms as an end-product of mycelium growth. Our experiments show that the system is capable of generating sufficient CO2 to induce increased tillering in rice seedlings, leading eventually to 18% more tillers and panicles in mature paddy-grown crop. We discuss the potential of eCO2 priming as a rapidly implementable, broadly applicable and sustainable system to increase tillering, and thus yield potential in rice.

Indoleamines Impart Abiotic Stress Tolerance and Improve Reproductive Traits in Hazelnuts.

Hazelnuts have recently gathered tremendous attention due to the expansion of the confectionary industry. However, the sourced cultivars fail to perform in initial phase of cultivation as they enter bare survival mode due to changes in climatic zones, for example, Southern Ontario, where the climate is continental, as opposed to the milder climate in Europe and Turkey. Indoleamines have been shown to counter abiotic stress and modulate vegetative and reproductive development of plants. Here, we examined the effect of indoleamines on the flowering response of the dormant stem cuttings of sourced hazelnut cultivars in controlled environment chambers. The stem cuttings were exposed to sudden summer-like conditions (abiotic stress) and the female flower development was assessed in relation to endogenous indoleamine titers. The sourced cultivars responded well to serotonin treatment by producing more flowers compared to the controls or other treatments. The probability of buds resulting in female flowers was highest in the middle region of the stem cuttings. It is interesting to note that the tryptamine titers of the locally adapted, and N-acetyl serotonin titers of native hazelnut cultivars, provided the best explanation for adaptation to the stress environment. Titers of both compounds were compromised in the sourced cultivars which resorted mostly to serotonin concentrations to counter the stress. The indoleamines tool kit identified in this study could be deployed in assessing cultivars for stress adaptation attributes.

Dairy Cows Offered Fresh Chicory Instead of Ensiled Pasture during an Acute Heat Challenge Produced More Milk and Had Lower Body Temperatures.

The frequency, duration, and intensity of heat waves in Australia are increasing. To reduce the impact of heat waves on milk production, novel management strategies are required. Altering the forage type and amount offered affect the heat load on dairy cows and offer potential strategies to ameliorate the effects of hot weather. Thirty-two multiparous, lactating Holstein-Friesian cows were assigned one of four dietary treatments: chicory high amount, chicory low amount, pasture silage high amount, or pasture silage low amount. These cows were exposed to a heat wave in controlled-environment chambers. Cows that were offered fresh chicory had similar feed intake to cows that were offered pasture silage (15.3 kg DM/d). However, cows that were offered chicory produced greater energy-corrected milk (21.9 vs. 17.2 kg/d) and had a lower maximum body temperature (39.4 vs. 39.6 °C) than cows that were offered pasture silage overall. Cows that were offered the high amount of forage had greater feed intake (16.5 vs. 14.1 kg DM/d) and energy corrected milk yield (20.0 vs. 17.9 kg/d) than cows that were offered the low amount, as intended, but with no difference in maximum body temperature (39.5 °C). We conclude that feeding chicory instead of pasture silage to dairy cows shows promise as a dietary strategy to ameliorate the effect of heat exposure, and there was no advantage in restricting feed amount.

Arsenic uptake and metabolism by a marine cyanobacteria PCC7002

Cyanobacteria Synechococcus PCC7002 is a typical marine bacterium that can tolerate salinity at around 20 ppt. In this study, cyanobacterium PCC7002 cells were incubated in a controlled environmental chamber for one week. Three different arsenic V (AsV) concentrations were added to the culture to observe the cyanobacterium’s capability to arsenic uptake. The arsenic uptake was then compared to the control media (without AsV addition). The higher the arsenic concentration added to the media, the more Arsenic occurs in the cells. Cyanobacteria cells could take up arsenic from their media at the range of 60-90% of the total arsenic exposed to the media, which showed their high arsenic tolerance. Speciation analysis using tandem HPLC and ICPMS showed that As-sugar is the main arsenic species in the cells, while inorganic arsenic is the main arsenic species in the media. Further analysis for signal confirmation using LCMS showed that the transformation of inorganic AsV into organic arsenic (As-sugar) confirmed the biotransformation of arsenic in the cyanobacteria cells. This result proves the vital role of cyanobacteria in arsenic cycling and biotransformation in marine environments.