High Temperature Stress Conditions Research Articles

STAY GREEN GENES FRAGMENT HOMOLOGY ANALYSIS OF INDONESIAN SORGHUM

Stay-green (SGR) is an essential trait in sorghum associated with grain yield under drought and high-temperature stress conditions. The study sought to analyze the homology of the stay-green gene fragment in Indonesian sorghum cultivars, comparing it with the SGR gene sequences in the GenBank database. Two primer pairs, designated as SGR_1 and SGR_2, got designed from the SGR gene of Sorghum bicolor and used to amplify seven sorghum genotypes. The DNA fragments of 300 bp and 1000 bp produced by SGR_1 and SGR_2, respectively, underwent sequencing. Amino acid analysis of the seven sorghum genotypes resulted in high homology with senescence-inducible chloroplast SGR-protein 1 from Zea mays and SGR-chloroplastic of Setaria italica. An observation on a conservative region with the SGR domain noticed SGR genes, derived from sorghum genotypes, clustered separately with those from other SGR genes available in the GenBank database. The first group consisted of a sorghum genotype (Samurai 2), the second group consisted of Super 2, Numbu, and Kawali, while the third group consisted of PI-150-20-A, Pahat, and B69 with coefficient similarity of 10%, 14%, and 30%, respectively. Although Indonesian sorghum has a different group in GenBank, it has similar nucleotide and amino acid sequences, with identity values of 95%-100% and 51%-100%, respectively. The amino acid diversity of the DNA fragments of the SGR gene is highly potential to develop molecular markers, especially the stay green character. The finding will support a sorghum breeding efficiently and precisely, especially for yield improvement under drought-stress conditions.

Enhancement of Photosynthetic Characteristics and Antioxidant Enzyme Activities on Chili Pepper Plants by Salicylic Acid Foliar Application under High Temperature and Drought Stress Conditions

Enhancement of Photosynthetic Characteristics and Antioxidant Enzyme Activities on Chili Pepper Plants by Salicylic Acid Foliar Application under High Temperature and Drought Stress Conditions

Space charge characteristics in epoxy/nano-MgO composites: Experiment and two-dimensional model simulation

Space charge accumulation in polymer dielectrics may lead to serious electric field distortion and even insulation failure during long-term operations of power equipment and electronic devices, especially under conditions of high temperature and direct current electric stress. The addition of nanoparticles into polymer matrices has been found effective in suppressing space charge accumulation and alleviating electric field distortion issues. Yet, the underlying mechanisms of nanoparticle doping remain a challenge to explore, especially from multi-dimensional composite insights. Here, a two-dimensional bipolar charge transport model with consideration of interface zones between organic/inorganic phases is proposed for the investigation into space charge behaviors of nanodielectrics. To validate the effectiveness and feasibility of the model, pulsed electroacoustic experiments are performed on epoxy/nano-MgO composites with different doping ratios of nanoparticles. Experimental observations match well with simulation anticipations, i.e., higher doping ratios of nanoparticles below the percolation threshold exhibit better capabilities to inhibit space charge accumulation. The deep traps (∼1.50 eV) generated in the interface zones are demonstrated to capture free charges, forming a reverse electric field in the region adjacent to electrodes and impeding the space charge migration toward the interior of the composite. This model is anticipated to provide theoretical insight for understanding space charge characteristics in polymer nanodielectrics and computing charge dynamics in extreme conditions where experiments are challenging to perform.

Impact of heat stress on agro-morphological, physio-chemical and fiber related paramters in upland cotton (Gossypium hirsutum L.) genotypes

The unpredictably changing climatic conditions, especially high temperatures, are putting a continuous threat to sustainable cotton production. The current study was designed to investigate the impact of heat stress on several morpho-physiological, biochemical, and fibre quality-related traits. The results revealed the presence of significant variations in agro-morphological, physio-chemical and staple length-related parameters for upland cotton genotypes and stress treatments. Further analysis of pooled data unveiled that heat stress had a detrimental impact on all studied plant traits. Severe reduction in plant height, nodes per plant, sympodial branches per plant, number of bolls per plant, ginning out-turn, and staple length were recorded under heat stress. A significant reduction in net photosynthetic rate (Pn) up to 28.6 % was observed in cotton genotype BH-200 (24.7 to 19.2 µmole m−2 s−1). The accumulation of hydrogen peroxide (H2O2) was increased from 7.1 % in BH-306 to 28.7 % in BH-200 under heat stress due to the incidence of oxidative stress. A substantial increase in the accumulation of antioxidants i.e., catalase (65 %–74 %), peroxidase (54 %–169 %), and superoxide dismutase (52 %–98 %) was seen under high-temperature stress conditions. The correlation coefficient analysis unveiled a significantly positive correlation of seed cotton yield with nodes per plant (r = 0.432*), net photosynthetic rate (r = 0.829**), peroxidase (r = 0.974**), and superoxide dismutase (r = 0.868**), under heat stress conditions. However, a negative but statistically significant correlation of seed cotton yield with ginning out turn (r = −0.466*), staple length (r = −0.898**), hydrogen peroxide (r = −0.955**) and catalase (r = −0.904**) was also observed. The overall results unveiled that cotton genotype BH-232 has a comparatively higher heat tolerance than other contesting genotypes while BH-306 showed the highest susceptibility to heat stress. Hence, BH-232 could be recommended after its approval for general cultivation in heat-prone areas of Pakistan.

Both AMP-activated and cAMP-dependent protein kinase regulate the expression of heat shock protein 70-2 gene in Neopyropia yezoensis

The upregulation of heat shock protein 70 (hsp70) gene under high temperature stress is a common phenomenon. Although heat shock protein-mediated stress responses play an important role in intertidal Neopyropia yezoensis, the detailed regulatory mechanism of the hsp70 gene expression is still unclear. Here, a full-length sequence of the hsp70-2 gene was cloned and its’ expression regulation was analyzed. There was an activating transcription factors element (ATFE) of cAMP-dependent protein kinase (PKA) was found at the gene promoter region and a highly conserved deduced amino acid sequence with calmodulin-binding activity was detected. Reagents implicated in the induction of the hsp70 gene were then selected to treat the algal samples at 24°C, and the photosynthetic parameters, transcription and translation of this gene were determined. Results showed that quercetin inhibited the transcription of the hsp70-2 gene, significantly decreased the synthesis of the HSP70-2 protein, and lowered the photosynthetic activity of N. yezoensis under high temperature stress conditions. Although the addition of trifluoperazine (TFP), an inhibitor of calmodulin (CAM), downregulated the photosynthetic parameters, the transcription of the hsp70-2 gene was not influenced at high temperature treatment, implying that CAM was not involved in the transcription of the hsp70-2 gene but involved in the heat stress reponding pathways. 5′-aminoimidasole-4-carboxamide-1-β-d-ribofuranoside (AICAR) promoted the synthesis of hsp70-2 transcripts significantly and HSP70-2 protein slightly, which indicated that AMPK regulated the induction of the hsp70-2 gene in N. yezoensis. Forskolin also promoted the upregulation of the hsp70-2 gene. Thus, both AMPK and cAMP-dependent protein kinase (PKA) could phosphorylate HSF and activate the expression of the hsp70-2 gene in N. yezoensis. However, there was no strict correlation between transcripts of the hsp70-2 gene and HSP70-2 protein contents. It was proposed that the posttranscriptional mechanisms were involved in regulating the synthesis of the HSP70-2 protein. Which allowed it to adapt to the extremely variable intertidal environments with an instant responding manner, since the accumulated transcripts could be translated rapidly when needed.

Genotype by Environment Interaction in Rice Under High Temperature Stress Condition in Cagayan

Twelve rice genotypes were planted in four municipalities of Cagayan (Iguig, Peñablanca, Solana, and Tuguegarao). It aimed to assess genotype by environment interaction (GEI) of rice cultivated by farmers in Cagayan as well as their stability. This study was also designed to identify genotypes suited to high temperature-prone areas and the most discriminating environment to screen genotypes for high temperature tolerance. During anthesis, the recorded maximum temperature ranged from 33.6-42.4°C in Iguig, 32.9-44.80C in Peñablanca, 32.1-40.5°C in Solana, and 32.6-41.1°C in Tuguegarao. Panicle and canopy temperature were lower than air temperature in Iguig and Peñablanca but higher in Solana and Tuguegarao. Variance due to genotype, environment and GEI were found significant (p≤0.05) for yield. Environment contributed the greatest proportion to yield which was 43.1% of the total variance, while genotype contributed 35.5%, and GEI 21.5%. Spikelet fertility, panicle length, number of grains per panicle, and grain weight were not significantly affected by GEI. However, panicle length and spikelet fertility were significantly affected by genotype and environment, while number of grains per panicle and grain weight were significantly affected only by environment. NSIC Rc 152, Rc 218, Rc 222, PR40330, and PR42026 were found high-yielding with wide adaptation to high temperature conditions. NSIC Rc 152 and PR40330 were the most outstanding genotypes. These genotypes can be used as parents for development of new heat-tolerant lines. Iguig was the best location for screening and selecting generally adapted genotypes under high temperature condition.

Effect of Recombinant Human Lubricin on Model Tear Film Stability.

PurposeTo investigate and quantify the effect of recombinant human lubricin (rh-lubricin) on model tear film stability.MethodsA custom-built, interferometry-based instrument called the Interfacial Dewetting and Drainage Optical Platform was used to create and record the spatiotemporal evolution of model acellular tear films. Image segmentation and analysis was performed in MATLAB to extract the most essential features from the wet area fraction versus time curve, namely the evaporative break-up time and the final wet area fraction (A10). These two parameters indicate the tear film stability in the presence of rh-lubricin in its unstressed and stressed forms.ResultsOur parameters successfully captured the trend of increasing tear film stability with increasing rh-lubricin concentration, and captured differences in rh-lubricin efficacy after various industrially relevant stresses. Specifically, aggregation and fragmentation caused by a 4-week, high temperature stress condition negatively impacted rh-lubricin's ability to maintain model tear film stability. Adsorbed rh-lubricin alone was not sufficient to resist break-up and maintain full area coverage of the model tear film surface.ConclusionsOur results demonstrate that fragmentation and aggregation can negatively impact rh-lubricin's ability to maintain a stable tear film. In addition, the ability of rh-lubricin to maintain wetted area coverage is due to both freely dispersed and adsorbed rh-lubricin.Translational RelevanceOur platform and analysis method provide a facile, intuitive, and clinically relevant means to quantify the effect of ophthalmic drugs and formulations intended for improving tear film stability, as well as capture differences between variants related to drug stability and efficacy.

Spermine-mediated metabolic homeostasis improves growth and stress tolerance in creeping bentgrass (Agrostis stolonifera) under water or high-temperature stress.

Plants have developed diverse defense strategies to reduce the detrimental effects of a wide range of environmental stresses. The objectives of this study were to explore the function of spermine (Spm) on mediating growth and physiological changes in water homeostasis, photosynthetic performance, and oxidative damage and to further examine the regulatory mechanism of Spm on global metabolites reprogramming and associated metabolic pathways in horticultural creeping bentgrass (Agrostis stolonifera) under water and heat stresses. The 21-days-old plants were pretreated with or without 100 μM Spm for 3 days and then subjected to water stress (17% polyethylene glycol 6000), high-temperature stress (40/35°C, day/night), or normal condition (control without water stress and heat stress) for 18 days. Results demonstrated that exogenous application of Spm could significantly increase endogenous polyamine (PAs), putrescine (Put), spermidine (Spd), and Spm contents, followed by effective alleviation of growth retardant, water imbalance, photoinhibition, and oxidative damage induced by water and heat stress. Metabolites' profiling showed that a total of 61 metabolites were differentially or commonly regulated by Spm in leaves. Spm upregulated the accumulation of mannose, maltose, galactose, and urea in relation to enhanced osmotic adjustment (OA), antioxidant capacity, and nitrogen metabolism for growth maintenance under water and heat stress. Under water stress, Spm mainly induced the accumulation of sugars (glucose-1-phosphate, sucrose-6-phosphate, fructose, kestose, maltotriose, and xylose), amino acids (glutamic acid, methionine, serine, and threonine), and organic acids (pyruvic acid, aconitic acid, and ketoglutaric acid) involved in the respiratory pathway and myo-inositol associated with energy production, the ROS-scavenging system, and signal transduction. In response to heat stress, the accumulation of alanine, glycine, gallic acid, malic acid, or nicotinic acid was specifically enhanced by Spm contributing to improvements in antioxidant potency and metabolic homeostasis. This study provides novel evidence of Spm-induced,tolerance to water and heat stresses associated with global metabolites reprogramming in favor of growth maintenance and physiological responses in horticultural plants.

Intracellular production of reactive oxygen species and a DAF-FM-related compound in Aspergillus fumigatus in response to antifungal agent exposure

Fungi are ubiquitously present in our living environment and are responsible for crop and infectious diseases. Developing new antifungal agents is constantly needed for their effective control. Here, we investigated fungal cellular responses to an array of antifungal compounds, including plant- and bacteria-derived antifungal compounds. The pathogenic fungus Aspergillus fumigatus generated reactive oxygen species in its hyphae after exposure to the antifungal compounds thymol, farnesol, citral, nerol, salicylic acid, phenazine-1-carbonic acid, and pyocyanin, as well as under oxidative and high-temperature stress conditions. The production of nitric oxide (NO) was determined using diaminofluorescein-FM diacetate (DAF-FM DA) and occurred in response to antifungal compounds and stress conditions. The application of reactive oxygen species or NO scavengers partly suppressed the inhibitory effects of farnesol on germination. However, NO production was not detected in the hyphae using the Greiss method. An LC/MS analysis also failed to detect DAF-FM-T, a theoretical product derived from DAF-FM DA and NO, in the hyphae after antifungal treatments. Thus, the cellular state after exposure to antifungal agents may be more complex than previously believed, and the role of NO in fungal cells needs to be investigated further.

Creep properties and relevant deformation mechanisms of two low-cost nickel-based single crystal superalloys at elevated temperatures

In this work, the creep properties and relevant deformation mechanisms of the two self-designed low-cost single crystal superalloys were studied under the conditions of 1038 °C/172 MPa and 982 °C/248 MPa. The experimental alloys both displayed superior creep properties than the typical second-generation single crystal superalloy René N5. During high temperature creep tests, the rafted γ′ phase became more and more twisted with the decrease of distance away from the fracture surface, which was caused by the existence of a stress gradient in the gauge length section of the fractured specimen. Under high temperature and low stress conditions, the Re-free alloy displayed denser dislocation networks under both test conditions. Based on the nodal reaction theory, the dislocation networks with different shapes formed by reactions of a/2<110> dislocations at the γ/γ′ interface. Furthermore, the morphology of dislocation networks could transform from initial rectangles to octagons and then to thick hexagons. Under the condition of 982 °C/248 MPa, some parallel dislocation arrays in γ′ particles caused by dislocations pile-up was found in the Re-low alloy, and the main obstacles to the motion of dislocations were K–W locks and a<010> superdislocations. Based on the calculated critical resolved shear stresses, the primary deformation mechanism of the two experimental alloys under elevated temperature and low stress conditions was identified as dislocations slipping in γ matrix and climbing over rafted γ′ phase.

Biochemical and Associated Agronomic Traits in Gossypium hirsutum L. under High Temperature Stress

Heat tolerance is a physiologically and genetically complex trait regulated by multiple genes. To investigate the genetic basis of heat tolerance, eight parents (five lines and three testers) and their fifteen F1 hybrids were evaluated under normal and high-temperature stress conditions for two consecutive years. Data were recorded for plant height, number of bolls, boll weight, seed cotton yield, ginning out turn (GOT%), H2O2, catalase, peroxidase, super-oxidase dismutase, total soluble proteins, carotenoids, chlorophyll a &amp; b contents, short fiber index, fiber strength, UHML, micronaire value, reflectance, and uniformity index. Line × tester analysis suggested that the contribution of lines was higher than testers. Non-additive gene action was observed for all studied traits. The variances of SCA were greater than GCA variances for all studied traits revealed that these traits were governed by a few largely dominant genes. Fb-Shaheen, Eagle-2 and JSQ White Gold were found good general combiner whereas the cross Fb-Shaheen × JSQ White Gold was a good specific combiner and revealed significant better parent heterosis for most of the traits during two years under normal and high temperature stress conditions. The information obtained could be utilized in a breeding program for the development of new synthetic varieties of heat tolerance.

Transport Characteristics of Interfacial Charge in SiC Semiconductor-Epoxy Resin Packaging Materials.

The silicon carbide (SiC) wide bandgap (WBG) semiconductor power device has been widely applied for its excellent properties. However, the charge accumulated in the interface of SiC semiconductor-related insulation packaging may lead to serious material performance degradation and failure, threatening the reliability and operation life of power devices. In this research, interface charge accumulation characteristics of SiC–epoxy resin double-layered material were investigated, and space charge injection, transport, and accumulation mechanisms, as well as the related temperature effect for the SiC–epoxy resin under polarization and depolarization conditions, were studied by the pulsed electro-acoustic (PEA) technique. The results show that a charge peak appears between the SiC–epoxy resin interface, which shows the same polarity as the SiC side electrode. Charge injects from the SiC electrode, transports along with the SiC semiconductor bulk due to the high mobility, and is blocked by the interface barrier. In addition, under high temperature and high electrical stress conditions, obvious charge accumulation occurs inside the epoxy resin bulk, which was captured by the deep traps. The charge accumulation of the SiC-insulation packaging material can influence the operation of the power device and should attract more attention.

Comparative Analysis of Canopy Cooling in Wheat under High Temperature and Drought Stress

The size and the weight of wheat grains vary across the length of each spike (Triticum aestivum L.). High temperature and water scarcity often reduce the single grain weight, and this reduction also varies across the spike length. Plants tend to cope with high temperature and drought stress through inherent mechanisms such ascanopy cooling through transpiration, which can contribute to yield stability. The effect of canopy cooling on the average grain weight at different positions in spike is still unknown. In this study, we planned to assess the role of canopy temperature, yield-related traits, and spike shape in final grain weight. For two years (2017–2018 and 2018–2019), fifteen diverse genotypes released for cultivation in different environmental conditions were grown in the field. They were examined for canopy temperature, spikelets spike−1, grain number spike−1, grain yield spike−1, and grain weight of the spike’s basal, median, and distal regions. The Pearson correlation coefficient (r) was obtained for all pair-wise combinations of traits under different treatments and spike shapes. The results indicated that cooler canopy is correlated to grain weight in normal spike shape at all three positions within the spike irrespective of stress. The advantage of the cooler canopy in improving grain-filling at basal, median, and distal regions was more conspicuous in the high temperature stress conditions compared to non-stressed and drought conditions.

The combination of hypoxia and high temperature affects heat shock, anaerobic metabolism, and pentose phosphate pathway key components responses in the white shrimp (Litopenaeus vannamei).

Due to global warming, world water bodies have higher temperatures and lower oxygen concentrations that affect aquatic species including the white shrimp Litopenaeus vannamei. This species withstands these conditions, but the information of the physiological responses that allow them to survive are scarce. We analyzed the effects of high temperature, hypoxia, reoxygenation, and the combination of these factors on the relative expression of selected genes: HSF1, Hsp70, p53, TIGAR, HIF-1α, and VEGF1-3 in gills of L. vannamei. Additionally, glucose, lactate, NADP, and NADPH were determined. HSF1 was up-regulated in the high temperature and oxygen stress conditions, but Hsp70 was up-regulated only in reoxygenation at both temperatures. HIF-1α was also up-regulated by reoxygenation in both temperatures. Meanwhile, the VEGF genes were not altered by the stress conditions, since none of them changed expression drastically. p53 relative expression remained stable at the tested stress conditions, which prompts to the maintenance of antioxidant defenses. TIGAR expression was induced in normoxia and hypoxia at high temperature, which induced NADPH content helping to scavenge reactive oxygen species (ROS). Additionally, high temperature caused higher glucose and lactate content in normoxia and hypoxia, indicating carbohydrate mobilization and a switch to anaerobic metabolism. The results showed that HSF1, the anaerobic metabolism and the pentose phosphate pathway (PPP) are crucial for the shrimp response to these abiotic stress conditions and contribute to their survival.

Effect of temperature and stress on high temperature creep behavior of Ni3Al-based single crystal superalloy

The creep behavior and dislocations mechanism of the Ni3Al-based single crystal alloy IC6SX with [001] orientation were investigated under the testing conditions of 1100 ​°C/137 ​MPa, 1100 ​°C/120 ​MPa and 1070 ​°C/137 ​MPa. It was observed that the temperature and stress had a significant effect on the high temperature creep life of the single crystal alloy. As the temperature was reduced from 1100 ​°C to 1070 ​°C, the creep life increased from 65.07 ​h to 313.8 ​h. As the stress was reduced to 120 ​MPa, the creep life increased to 243.3 ​h. Under the high temperature and low stress condition the dislocations entered the γ′ phase by climbing caused by the atomic diffusion, instead of slipping.

Response of Tomato (Solanum lycopersicum L.) Genotypes to Heat Stress Using Morphological and Expression Study.

Due to unfavorable environmental conditions, heat stress is one of the significant production restrictions for the tomato (Solanum lycopersicum L.) crop. The tomato crop is considered an important vegetable crop globally and represents a model plant for fruit development research. The heat shock factor (HSF) gene family contains plant-specific transcription factors (TFs) that are highly conserved and play a key role in plant high-temperature stress responses. The current study was designed to determine the relative response of heat stress under three different temperatures in the field condition to determine its relative heat tolerance. Furthermore, the study also characterized heat shock genes in eight tomato genotypes under different temperature regimes. The expressions of each gene were quantified using qPCR. The descriptive statistics results suggested a high range of diversity among the studied variables growing under three different temperatures. The qPCR study revealed that the SlyHSF genes play an important role in plant heat tolerance pathways. The expression patterns of HSF genes in tomatoes have been described in various tissues were determined at high temperature stress. The genes, SlyHSFs-1, SlyHSFs-2, SlyHSFs-8, SlyHSFs-9 recorded upregulation expression relative to SlyHSFs-3, SlyHSFs-5, SlyHSFs-10, and SlyHSFs-11. The genotypes, Strain B, Marmande VF, Pearson’s early, and Al-Qatif-365 recorded the tolerant tomato genotypes under high-temperature stress conditions relative to other genotypes. The heat map analysis also confirmed the upregulation and downregulation of heat shock factor genes among the tomato genotypes. These genotypes will be introduced in the breeding program to improve tomato responses to heat stress.

Unraveling Heat Tolerance in Upland Cotton (Gossypium hirsutum L.) Using Univariate and Multivariate Analysis.

The ever-changing global environment currently includes an increasing ambient temperature that can be a devastating stress for organisms. Plants, being sessile, are adversely affected by heat stress in their physiology, development, growth, and ultimately yield. Since little is known about the response of biochemical traits to high-temperature ambiance, we evaluated eight parental lines (five lines and three testers) and their 15 F1 hybrids under normal and high-temperature stress to assess the impact of these conditions over 2 consecutive years. The research was performed under a triplicate randomized complete block design including a split-plot arrangement. Data were recorded for agronomic, biochemical, and fiber quality traits. Mean values of agronomic traits were significantly reduced under heat stress conditions, while hydrogen peroxide, peroxidase, total soluble protein, superoxide dismutase, catalase (CAT), carotenoids, and fiber strength displayed higher mean values under heat stress conditions. Under both conditions, high genetic advance and high heritability were observed for seed cotton yield (SCY), CAT, micronaire value, plant height, and chlorophyll-a and b content, indicating that an additive type of gene action controls these traits under both the conditions. For more insights into variation, Pearson correlation analysis and principal component analysis (PCA) were performed. Significant positive associations were observed among agronomic, biochemical, and fiber quality-related traits. The multivariate analyses involving hierarchical clustering and PCA classified the 23 experimental genotypes into four groups under normal and high-temperature stress conditions. Under both conditions, the F1 hybrid genotype FB-SHAHEEN × JSQ WHITE GOLD followed by Ghuari-1, CCRI-24, Eagle-2 × FB-Falcon, Ghuari-1 × JSQ White Gold, and Eagle-2 exhibited better performance in response to high-temperature stress regarding the agronomic and fiber quality-related traits. The mentioned genotypes could be utilized in future cotton breeding programs to enhance heat tolerance and improve cotton yield and productivity through resistance to environmental stressors.

Physiological Characteristics of Cultivated Tepary Bean (Phaseolus acutifolius A. Gray) and Its Wild Relatives Grown at High Temperature and Acid Soil Stress Conditions in the Amazon Region of Colombia.

Common bean (Phaseolus vulgaris L.) is sensitive to different types of abiotic stresses (drought, high temperature, low soil fertility, and acid soil), and this may limit its adaptation and consequently to its yield under stress. Because of this, a sister species, tepary bean (Phaseolus acutifolius A. Gray), has recently gained attention in breeding for improved abiotic stress tolerance in common bean. In this study, we evaluated the adaptation of 302 accessions of tepary bean (Phaseolus acutifolius A. Gray) and its wild relatives (grouped in four types of tepary bean genetic resource: cultivated, acutifolius regressive, acutifolius wild, tenuifolius wild) when grown under high temperature and acid soil conditions with aluminum toxicity in the Amazon region of Colombia. Our objective was to determine differences among four types of tepary bean genetic resource in their morpho-phenological, agronomic, and physiological responses to combined high temperature and acid soil stress conditions. We found that cultivated P. acutifolius var acutifolius presented a greater number of pods per plant, as well as larger seeds and a greater number of seeds per pod. Some traits, such as root biomass, days to flowering and physiological maturity, specific leaf area, and stomatal density, showed significant differences between types of tepary bean genetic resource, probably contributing to difference in adaptation to combined stress conditions of high temperature and acid soil conditions. The photochemical quenching (qP) was higher in cultivated P. acutifolius var. acutifolius, while energy dissipation by non-photochemical quenching (NPQ) in the form of heat and the coefficient of non-photochemical dissipation (qN) were higher in acutifolius regressive and tenuifolius wild accessions. We have identified 6 accessions of cultivated and 19 accessions of tenuifolius wild that exhibited grain yields above 1800 kg ha−1. These accessions could be suitable to use as parents to improve dry seed production of tepary bean under combined stress conditions of high temperature and acid soil.

A Low-Cost, Easy-to-Assemble Device to Prevent Infant Hyperthermia under Conditions of High Thermal Stress.

High ambient temperature and humidity greatly increase the risk of hyperthermia and mortality, particularly in infants, who are especially prone to dehydration. World areas at high risk of heat stress include many of the low- and middle-income countries (LMICs) where most of their inhabitants have no access to air conditioning. This study aimed to design, evaluate, and test a novel low-cost and easy-to-assemble device aimed at preventing the risk of infant hyperthermia in LMICs. The device is based on optimizing negative heat transfer from a small amount of ice and transferring it directly to the infant by airflow of refrigerated air. As a proof of concept, a device was assembled mainly using recycled materials, and its performance was assessed under laboratory-controlled conditions in a climatic chamber mimicking realistic stress conditions of high temperature and humidity. The device, which can be assembled by any layperson using easily available materials, provided sufficient refrigerating capacity for several hours from just 1–2 kg of ice obtained from a domestic freezer. Thus, application of this novel device may serve to attenuate the adverse effects of heat stress in infants, particularly in the context of the evolving climatic change trends.

Effects of High-Temperature Stress during Plant Cultivation on Tomato (Solanum lycopersicum L.) Fruit Nutrient Content

Agriculture is among the sectors that will be impacted first and most by the adverse effects of climate change. Therefore, developing new high-temperature tolerant varieties is an essential economic measure in adaptation to near-future climate change. Likewise, there is a growing interest in increasing the antioxidant content of crops to improve food quality and produce crops with high-stress tolerance. Tomato is the most grown and consumed species in horticultural plants; however, it is vulnerable to 35°C and above high temperatures during cultivation. This study used twenty high-temperature tolerant, two susceptible genotypes, and two commercial tomato varieties in the open field. The experiment was applied under control and high-temperature stress conditions based on a randomized block design with 4 replications and 12 plants per repetition. The study investigated the fruit’s selected quality properties and antioxidant compounds, namely, total soluble solutes (Brix), titratable acidity, pH, electrical conductivity (EC), lycopene, β-carotene, and vitamin C, along with total phenols and total flavonoids under control and stress conditions. As a result, in general, total soluble solutes, titratable acidity, total phenol, and vitamin C contents under high-temperature conditions were determined to increase in tolerant tomato genotypes, while decreases were noted for pH, EC, total flavonoids, lycopene, and β-carotene. However, different specific responses on the basis of genotypes and useful information for breeding studies have been identified. These data on fruit nutrient content and antioxidants will be helpful when breeding tomato varieties to be grown in high-temperature conditions.