High Night Temperature Research Articles

Retraction: Responses of Rapid Viscoanalyzer Profile and Other Rice Grain Qualities to Exogenously Applied Plant Growth Regulators under High Day and High Night Temperatures.

Retraction: Responses of Rapid Viscoanalyzer Profile and Other Rice Grain Qualities to Exogenously Applied Plant Growth Regulators under High Day and High Night Temperatures.

Maize Responses to High Night Temperature During Postflowering and Early Grain Filling: Effects on Yield Components, Kernel Growth and Dry Matter Allocation

ABSTRACTWarm night frequency has increased steadily in the last years across maize production regions, but high night temperature (HNT) effects on growth, grain yield and maize dry matter allocation (DMA) to different plant organs remain poorly understood. In this study, we aimed to (i) analyse the DMA among reproductive and vegetative organs, (ii) evaluate the individual kernel weight through its determinants, rate and duration of grain filling and (iii) quantify changes in grain yield per plant and its components due to HNT during the postflowering and early grain‐filling period. Field‐grown maize was subjected to HNT induced by shelters during a 15‐ or 30‐day period after silking, encompassing the postflowering period (HNT15) and extending the heating into early grain filling (HNT30), respectively. The HNT was applied from 1900 to 0700 h while control plots remained at ambient night temperature (ANT). Kernel number per plant was decreased under both temperature regimes (i.e., HNT15 and HNT30); however, significant reductions in grain yield were only observed under HNT30. The DMA during the heating period was differentially affected by the duration of heating. While DMA to the stem was likewise reduced by both heating treatments, the partition to the uppermost ear was only reduced under HNT30. Related to the lack of response to HNT treatments of the rate and duration of grain filling, the individual kernel weight was not reduced. The source‐sink ratio was not affected by HNT, meanwhile, the apparent reserve use was significantly reduced under HNT30. Our results demonstrate that the magnitude of HNT effects is subjected to the duration of the heating period, but also depends on the intensity of heating explored across seasons, especially for kernel number and grain yield.

Tissue- and time-dependent metabolite profiles during early grain development under normal and high night-time temperature conditions

BackgroundWheat grain development in the first few days after pollination determines the number of endosperm cells that influence grain yield potential and is susceptible to various environmental conditions, including high night temperatures (HNTs). Flag leaves and seed-associated bracts (glumes, awn, palea, and lemma) provide nutrients to the developing seed. However, the specific metabolic roles of these tissues are uncertain, especially their dynamics at different developmental stages and the time in a day. Tissue- and time-dependent metabolite profiling may hint at the metabolic roles of tissues and the mechanisms of how HNTs affect daytime metabolic status in early grain development.ResultsThe metabolite profiles of flag leaf, bract, seed (embryo and endosperm), and entire spike were analyzed at 12:00 (day) and 23:00 (night) on 2, 4, and 6 days after fertilization under control and HNT conditions. The metabolite levels in flag leaves and bracts showed day/night oscillations, while their behaviors were distinct between the tissues. Some metabolites, such as sucrose, cellobiose, and succinic acid, showed contrasting oscillations in the two photosynthetic tissues. In contrast, seed metabolite levels differed due to the days after fertilization rather than the time in a day. The seed metabolite profile altered earlier in the HNT than in the control condition, likely associated with accelerated grain development caused by HNT. HNT also disrupted the day/night oscillation of sugar accumulation in flag leaves and bracts.ConclusionsThese results highlight distinct metabolic roles of flag leaves and bracts during wheat early seed development. The seed metabolite levels are related to the developmental stages. The early metabolic events in the seeds and the disruption of the day/night metabolic cycle in photosynthetic tissues may partly explain the adverse effects of HNT on grain yield.

Higher Grain-Filling Rate in Inferior Spikelets of Tolerant Rice Genotype Offset Grain Yield Loss under Post-Anthesis High Night Temperatures

Increased nighttime respiratory losses decrease the amount of photoassimilates available for plant growth and yield. We hypothesized that the increased respiratory carbon loss under high night temperatures (HNT) could be compensated for by increased photosynthesis during the day following HNT exposure. Two rice genotypes, Vandana (HNT-sensitive) and Nagina 22 (HNT-tolerant), were exposed to HNT (4 °C above the control) from flowering to physiological maturity. They were assessed for alterations in the carbon balance of the source (flag leaf) and its subsequent impact on grain filling dynamics and the quality of spatially differentiated sinks (superior and inferior spikelets). Both genotypes exhibited significantly higher night respiration rates. However, only Nagina 22 compensated for the high respiration rates with an increased photosynthetic rate, resulting in a steady production of total dry matter under HNT. Nagina 22 also recorded a higher grain-filling rate, particularly at 5 and 10 d after flowering, with 1.5- and 4.0-fold increases in the translocation of 14C sugars to the superior and inferior spikelets, respectively. The ratio of photosynthetic rate to respiratory rate on a leaf area basis was negatively correlated with spikelet sterility, resulting in a higher filled spikelet number and grain weight per plant, particularly for inferior grains in Nagina 22. Grain quality parameters such as head rice recovery, high-density grains, and gelatinization temperature were maintained in Nagina 22. An increase in the rheological properties of rice flour starch in Nagina 22 under HNT indicated the stability of starch and its ability to reorganize during the cooling process of product formation. Thus, our study showed that sink adjustments between superior and inferior spikelets favored the growth of inferior spikelets, which helped to offset the reduction in grain weight under HNT in the tolerant genotype Nagina 22.

Impact of Temperature Variations on Rice Production

The mean temperature might rise up to range of 2.0–4.5°C worldwide by the end of this century. Climatic variables affect the growth and development of the crop differently at different growth stages. The rate of development of a crop depends on the climate. Temperature is the primary factor that influences the growth and productivity of crops. Higher or lower temperatures than the optimum lead to improper crop development and affect rice's phenological stages. Extreme temperature may lead to early maturity of the crop and lower temperature lead to prolonged maturity of the crop which in both cases leads to a decrease in yield. A moderate increase in temperature will not have severe implications, but an increase in average temperature by 20 C will likely have strong negative effects on rice crop production. In several studies, it has been reported that high night temperature decreases the yield potential of rice. Whereas, respiratory losses have been shown to increase due to higher day temperature, leaf conductance and net assimilation rates during the day were reported to be higher.

High night temperature stress on rice (Oryza sativa) - insights from phenomics to physiology. A review.

Rice (Oryza sativa ) faces challenges to yield and quality due to urbanisation, deforestation and climate change, which has exacerbated high night temperature (HNT). This review explores the impacts of HNT on the physiological, molecular and agronomic aspects of rice growth. Rise in minimum temperature threatens a potential 41% reduction in rice yield by 2100. HNT disrupts rice growth stages, causing reduced seed germination, biomass, spikelet sterility and poor grain development. Recent findings indicate a 4.4% yield decline for every 1°C increase beyond 27°C, with japonica ecotypes exhibiting higher sensitivity than indica. We examine the relationships between elevated CO2 , nitrogen regimes and HNT, showing that the complexity of balancing positive CO2 effects on biomass with HNT challenges. Nitrogen enrichment proves crucial during the vegetative stage but causes disruption to reproductive stages, affecting grain yield and starch synthesis. Additionally, we elucidate the impact of HNT on plant respiration, emphasising mitochondrial respiration, photorespiration and antioxidant responses. Genomic techniques, including CRISPR-Cas9, offer potential for manipulating genes for HNT tolerance. Plant hormones and carbohydrate enzymatic activities are explored, revealing their intricate roles in spikelet fertility, grain size and starch metabolism under HNT. Gaps in understanding genetic factors influencing heat tolerance and potential trade-offs associated with hormone applications remain. The importance of interdisciplinary collaboration is needed to provide a holistic approach. Research priorities include the study of regulatory mechanisms, post-anthesis effects, cumulative HNT exposure and the interaction between climate variability and HNT impact to provide a research direction to enhance rice resilience in a changing climate.

Systematic identification and characterization of microRNAs with target genes involved in high night temperature stress at the filling stage of rice.

High night temperature stress is one of the main environmental factors affecting rice yield and quality. More and more evidence shows that microRNA (miRNA) plays an important role in various abiotic stresses. However, the molecular network of miRNA regulation on rice tolerance to high night temperatures remains unclear. Here, small RNA, transcriptome and degradome sequencing were integrated to identify differentially expressed miRNAs, genes, and key miRNA-target gene pairs in rice heat-sensitive and heat-tolerant lines at the filling stage suffering from high night temperature stress. It was discovered that there were notable differences in the relative expression of 102 miRNAs between the two rice lines under stress. Meanwhile, 5263 and 5405 mRNAs were differentially expressed in the heat-sensitive line and heat-tolerant line, and functional enrichment analysis revealed that these genes were involved in heat-related processes and pathways. The miRNAs-mRNAs target relationship was further verified by degradome sequencing. Eventually, 49 miRNAs-222 mRNAs target pairs with reverse expression patterns showed significant relative expression changes between the heat-tolerant and the heat-sensitive line, being suggested to be responsible for the heat tolerance difference of these two rice lines. Functional analysis of these 222 mRNA transcripts showed that high night temperature-responsive miRNAs targeted these mRNAs involved in many heat-related biological processes, such as transcription regulation, chloroplast regulation, mitochondrion regulation, protein folding, hormone regulation and redox process. This study identified possible miRNA-mRNA regulation relationships in response to high night temperature stress in rice and potentially contributed to heat resistance breeding of rice in the future.

Physiological and Biochemical Effect of Elevated Night Temperature Stress on Bread Wheat (Triticum aestivum L.)

A laboratory experimentation was done in the Department of Plant Physiology, Institute of Agricultural Sciences, Banaras Hindu University to evaluate elevated night temperature effect in wheat (Triticum aestivum L.) to see the response in some antioxidant and biochemical parameters in two wheat cultivars viz. HUW-234 (comparatively tolerant to heat stress) and sonalika (comparatively susceptible to heat stress). A significance difference was recorded in the parameters pertaining to antioxidant system includes catalase, SOD and APX activity were found to increase substantially when the plants kept under stress conditions (250C/ 240C day and night temperature) than the plants kept under controlled condition (250C/150C day and night temperature). The percent increase in the antioxidant enzyme activity was found to be more in the tolerant genotype (HUW-234) than in the susceptible genotype (Sonalika). There was 23.52 % increase was reported in the catalase activity by tolerant genotype when kept under stress conditions than those kept under control. Significant reductions were reported in most of the photosynthetic and membrane parameters viz., chlorophyll ‘a’, chlorophyll ‘b’ and membrane thermostability index. Similar percent reduction was reported with respect to biochemical parameters (total protein content, starch content and soluble sugar content) in the susceptible variety kept under high night temperature regime. Based on the pooled data of two-year experimentation it can be concluded that variety HUW-234 was found to be more tolerant than variety sonalika to HNT stress.
 Key Words: High night temperature, Wheat, Catalase activity, Anti-oxidant system.

Effect of high night temperature on leaf senescence, physiological activity, and growth in soybean

Physiological processes that cause a negative growth response to high night temperatures (HNTs) were investigated in soybean. An HNT (28​°C) was established in a phytotron during the first (HL) and second (LH) halves of the reproductive stage and the entire (HH) reproductive stage, along with a continuously low (LL) night temperature (22​°C). Plant biomass was lower in HH than that in LL, whereas the harvest index was relatively stable. N accumulation in the plants tended to decline with HNT. The leaf area and leaf N concentration tended to be lower in HL and HH than in LL, suggesting an earlier onset of leaf senescence under HNT in the early reproductive stage. The light-saturated leaf photosynthetic rate was lower in HH than in LL during the late reproductive stage, associated with a low stomatal conductance and leaf photosynthetic rate per intercellular CO2 concentration. A slower rise in the leaf photosynthetic rate in the morning occurred likely because of the HNT, coinciding with the low leaf water potential at predawn and low leaf photosynthetic rate to intercellular CO2 concentration ratio. A moderately increasing gradient of night temperature from 21.7 to 23.9​°C was created in a mini-field in another experiment using a temperature gradient chamber, and in this experiment, crop growth and N dynamics were similar to those obtained in the phytotron study. These results suggest that the biomass growth of soybean is affected by HNT, particularly during the early reproductive stage.

Gluten subfractions of wheat storage proteins are affected by high night temperature during grain formation

AbstractGluten (gliadin + glutenin) protein in wheat flour is affected by high temperature (day and/or night) resulting in undesirable consequences on dough quality. A study was conducted with early and late‐maturing wheat genotypes, to assess the spatial (superior‐ central and inferior‐ apical and basal spikelets) variation in the composition of gluten subfractions in the developing ear under high night temperature (HNT). We hypothesised that protein content in the superior and inferior grains may show a differential quantitative and qualitative response to HNT. HNT resulted in a significant increase in protein content which exhibited a strong (r = −0.44*) negative correlation with sedimentation volume (SV) that determines baking quality. The late‐maturity genotypes were more responsive to HNT with changes in ω‐5 and γ gliadin subfractions of both superior and inferior spikelets, though a consistent trend was not established. The proportion of high molecular weight (HMW) glutenins increased, whereas low molecular weight (LMW) glutenins reduced in most of the genotypes under HNT. Both HMW and LMW glutenins revealed significant positive (r = 0.43* and r = 0.81***, respectively) correlation with SV. The expression analysis of genes for gluten subfractions showed a significant decrease in transcript abundance of α, ω‐5, γ, HMW, and LMW fractions under HNT.

Development potential of nanoenabled agriculture projected using machine learning

The controllability and targeting of nanoparticles (NPs) offer solutions for precise and sustainable agriculture. However, the development potential of nanoenabled agriculture remains unknown. Here, we build an NP-plant database containing 1,174 datasets and predict (R2 higher than 0.8 for 13 random forest models) the response and uptake/transport of various NPs by plants using a machine learning approach. Multiway feature importance analysis quantitatively shows that plant responses are driven by the total NP exposure dose and duration and plant age at exposure, as well as the NP size and zeta potential. Feature interaction and covariance analysis further improve the interpretability of the model and reveal hidden interaction factors (e.g., NP size and zeta potential). Integration of the model, laboratory, and field data suggests that Fe2O3 NP application may inhibit bean growth in Europe due to low night temperatures. In contrast, the risks of oxidative stress are low in Africa because of high night temperatures. According to the prediction, Africa is a suitable area for nanoenabled agriculture. The regional differences and temperature changes make nanoenabled agriculture complicated. In the future, the temperature increase may reduce the oxidative stress in African bean and European maize induced by NPs. This study projects the development potential of nanoenabled agriculture using machine learning, although many more field studies are needed to address the differences at the country and continental scales.

A Deep Learning Framework for Processing and Classification of Hyperspectral Rice Seed Images Grown under High Day and Night Temperatures.

A framework combining two powerful tools of hyperspectral imaging and deep learning for the processing and classification of hyperspectral images (HSI) of rice seeds is presented. A seed-based approach that trains a three-dimensional convolutional neural network (3D-CNN) using the full seed spectral hypercube for classifying the seed images from high day and high night temperatures, both including a control group, is developed. A pixel-based seed classification approach is implemented using a deep neural network (DNN). The seed and pixel-based deep learning architectures are validated and tested using hyperspectral images from five different rice seed treatments with six different high temperature exposure durations during day, night, and both day and night. A stand-alone application with Graphical User Interfaces (GUI) for calibrating, preprocessing, and classification of hyperspectral rice seed images is presented. The software application can be used for training two deep learning architectures for the classification of any type of hyperspectral seed images. The average overall classification accuracy of 91.33% and 89.50% is obtained for seed-based classification using 3D-CNN for five different treatments at each exposure duration and six different high temperature exposure durations for each treatment, respectively. The DNN gives an average accuracy of 94.83% and 91% for five different treatments at each exposure duration and six different high temperature exposure durations for each treatment, respectively. The accuracies obtained are higher than those presented in the literature for hyperspectral rice seed image classification. The HSI analysis presented here is on the Kitaake cultivar, which can be extended to study the temperature tolerance of other rice cultivars.

Evaluating metabolic and genomic data for predicting grain traits under high night temperature stress in rice.

The asymmetric increase in average nighttime temperatures relative to increase in average daytime temperatures due to climate change is decreasing grain yield and quality in rice. Therefore, a better genome-level understanding of the impact of higher night temperature stress on the weight of individual grains is essential for future development of more resilient rice. We investigated the utility of metabolites obtained from grains to classify high night temperature (HNT) conditions of genotypes, and metabolites and single-nucleotide polymorphisms (SNPs) to predict grain length, width, and perimeter phenotypes using a rice diversity panel. We found that the metabolic profiles of rice genotypes alone could be used to classify control and HNT conditions with high accuracy using random forest or extreme gradient boosting. Best linear unbiased prediction and BayesC showed greater metabolic prediction performance than machine learning models for grain-size phenotypes. Metabolic prediction was most effective for grain width, resulting in the highest prediction performance. Genomic prediction performed better than metabolic prediction. Integrating metabolites and genomics simultaneously in a prediction model slightly improved prediction performance. We did not observe a difference in prediction between the control and HNT conditions. Several metabolites were identified as auxiliary phenotypes that could be used to enhance the multi-trait genomic prediction of grain-size phenotypes. Our results showed that, in addition to SNPs, metabolites collected from grains offer rich information to perform predictive analyses, including classification modeling of HNT responses and regression modeling of grain-size-related phenotypes in rice.

Effects of high night temperature on soybean yield and compositions.

Soybean is sensitive to light and temperature. Under the background of global asymmetric climate warming. The increase of night temperature may have an important impact on soybean yield. In this study, three varieties with different level of protein were planted under 18°C and 28°C night temperatures for investigating the effects of high night temperatures on soybean yield formation and the dynamic changes of non-structural carbohydrates (NSC) during the seed filling period (R5-R7). The results indicated that high night temperatures resulted in smaller seed size, lower seed weight, and a reduced number of effective pods and seeds per plant, and thus, a significant reduction in yield per plant. Analysis of the seed composition variations showed carbohydrates were more substantially affected by high night temperature than protein and oil. We observed "carbon hunger" caused by high night temperature increased photosynthesis and sucrose accumulation in the leaves during the early stage of high night temperature treatment. With elongated treated time, the excessive carbon consumption led to the decrease of sucrose accumulation in soybean seeds. Transcriptome analysis of leaves after 7 days of treatment showed that the expression of most sucrose synthase and sucrose phosphatase genes decreased significantly under the high night temperature. Which could be another important reason for the decrease of sucrose. These findings provided a theoretical basis for enhancing the tolerance of soybean to high night temperature.

Hydrogen Peroxide and GA3 Levels Regulate the High Night Temperature Response in Pistils of Wheat (Triticum aestivum L.).

High night temperature (HNT) impairs crop productivity through the reproductive failure of gametes (pollen and pistil). Though female gametophyte (pistil) is an equal partner in the seed-set, the knowledge of the antioxidant system(s) and hormonal control of HNT tolerance or susceptibility of pistils is limited and lacking. The objectives of this study were to determine the antioxidant mechanism for homeostatic control of free radicals, and the involvement of abscisic acid (ABA) and gibberellic acid (GA3) in HNT stress protection in the wheat pistils of contrasting wheat genotypes. We hypothesized that HNT tolerance is attributed to the homeostatic control of reactive oxygen species (ROS) and hormonal readjustment in pistils of the tolerant genotype. The ears of two contrasting wheat genotypes-HD 2329 (susceptible) and Raj 3765 (tolerant) were subjected to two HNTs (+5 °C and +8 °C) over ambient, in the absence and presence of dimethylthiourea (DMTU), a chemical trap of hydrogen peroxide (H2O2). Results showed that HNTs significantly increased ROS in pistils of susceptible genotype HD 2329 to a relatively greater extent compared to tolerant genotype Raj 3765. The response was similar in the presence or absence of DMTU, but the H2O2 values were lower in the presence of DMTU. The ROS levels were balanced by increased activity of peroxidase under HNT to a greater extent in the tolerant genotype. Cytosolic glyceraldehyde-3-phosphate dehydrogenase (GAPC) activity was inversely related to H2O2 production within a critical range in Raj 3765, indicating its modulation by H2O2 levels as no change was observed at the transcriptional level. The hormonal status showed increased ABA and decreased GA3 contents with increasing temperature. Our study elucidates the role of H2O2 and GA3 in stress tolerance of pistils of tolerant genotype where GAPC acts as a ROS sensor due to H2O2-mediated decrease in its activity.

Plant Responses to High-Temperature Stress

Temperature above optimal for the specie will reduce photosynthesis and increase dark respiration and photorespiration in part due to increased solubility of O2 compared to CO2 but also due to the decrease in CO2 mesophyll conductance to the chloroplast. In addition, night temperature has a great impact on carbohydrates balance because high night temperature reduces the efficiency of the generation of ATP from respiration consuming more sugars to maintain growth. Another effect on species that have their cycle sensitive to temperature, inducing the reproductive phase soon or later depending on air temperature. The majority of plants adapted to high temperatures above their optimum synthesize small HSPs, which will maintain the integrity and reactivity of bigger enzymes and membranes. Therefore, plant adaptation to high temperatures is a multigenic characteristic depending on biochemical, physiological, and morphological traits.

Impact of High Night Temperature on Yield and Pasting Properties of Flour in Early and Late-Maturing Wheat Genotypes.

The inexorable process of climate change in terms of the rise in minimum (nighttime) temperature delineates its huge impact on crop plants. It can affect the yield and quality of various crops. We investigated the effect of high night temperature (HNT) (+2.3 °C over ambient) from booting to physiological maturity on the yield parameters, grain growth rate (GGR), starch content, composition, and flour rheological properties in early (HI 1544, HI 1563) and late-maturing (HD 2932) wheat genotypes. The change in yield under HNT was highly correlated with grain number per plant (r = 0.740 ***) and hundred-grain weight (r = 0.628 **), although the reduction in grain weight was not significantly different. This was also reflected as an insignificant change in starch content (except in HI 1544). Under HNT, late-sown genotypes (HI 1563 and HD 2932) maintained high GGR compared to the timely sown (HI 1544) genotype during the early period of grain growth (5 to 10 days after anthesis), which declined during the later phase of grain development. The increased rheological properties under HNT can be attributed to a significant reduction in the amylose to amylopectin (AMY/AMP) ratio in early-maturity genotypes (HI 1544 and HI 1563). The AMY/AMP ratio was positively correlated to flour rheological parameters (except setback from peak) under HNT. Our study reports the HNT-induced change in the amylose/amylopectin ratio in early maturing wheat genotypes, which determines the stability of flour starches for specific end-use products.

Characterizing the Potato Growing Regions in India Using Meteorological Parameters.

Currently, the multi-location testing of advanced hybrids in India is carried out at 25 centers under the All India Co-ordinated Research Project on Potato (AICRP-P), which is spread across the country. These centres have been chosen to represent different potato growing regions based on soil and agronomic features. However, the reliable deployment of the newly bred varieties in different regions requires a scientific delineation of potato growing zones with homogenous climates. The present study was undertaken to develop homogenous zones in the Indian sub-continent based on the environmental parameters of the potato growing season. A total of 1253 locations were identified across the country as having a plausible potato growing season of at least 70 days with suitable thermal limits. Six variables including five meteorological parameters including Physiological days (P days), Growing degree days (GDD), Mean daily temperature, Mean night temperature and Mean daily incident solar radiation, together with altitude as the sixth variable, were used for Agglomerative Hierarchical Clustering (AHC) and the Principal Component Analysis by Multidimensional Scaling (MDS) technique to derive identical classes. The thematic map of the classes was overlaid on potato growing districts of India using ArcGIS 9.1 software. The study clearly depicted that the clustering technique can effectively delineate the target population of environments (TPE) for potato genotypes performing well at different testing environments in India. The study also identifies target locations for future focus on breeding strategies, especially the high night temperature class having a large expanse in India. This is also vital in view of the impending climate change situation.

Effect of high night temperature and CO2 on yield and seed quality of summer green gram (Vigna radiata) under soil plant atmospheric research (SPAR)

An experiment was designed in Coimbatore, Tamil Nadu during two successive summer seasons, 2021 and 2022, to investigate the effects of high night temperature (HNT) (ambient+3oC) and CO2 (600ppm) on the yield and seed quality parameters of green gram under ten treatments in SPAR (Soil Plant Atmospheric Research) and ambient conditions. The objective of this research was to i) quantify the short-term effects of HNT and CO2 on yield contribution factors and (ii) quantify seed quality parameters employing biochemical analysis. Green gram yield and quality parameters were significantly reduced under HNT and CO2 when compared to ambient condition. Pooled data from two successive summer seasons revealed that when stress was imposed from (i) 43 to 49 DAS (Day After Sowing), the number of flowers dropped per plant significantly increased by 41.3% (ii) 29 to 35 DAS, pod setting percentage decreased by 18.5% (iii) 36 to 42 DAS, grain yield and biomass/plant decreased by 26.9 % and 29.3%respectively. In aspects of seed quality parameters, data revealed that under stress (i) Seed protein decreased by 20.5% from 50 to 56 DAS. (ii) Total sugars, polyphenols, calcium and iron decreased by 17.7, 19.9, 19.9 and 37.3%, respectively from 43 to 49 DAS. (iii) Seed moisture was reduced by 19.7% during 57 to 63 DAS. (iv) The levels of proline and phytic acid increased by 64.3 and 33.8%, respectively, from 50 to 56 DAS and 43 to 49 DAS. Overall, green gram yield was adversely affected on three treatments from 35 to 56 DAS (flower initiation stage to pod filling stage) and seed quality parameters such as protein, total sugars, polyphenols, seed moisture, proline, phytic acid, calcium and iron were reduced under HNT and CO2 from 50% flowering to pod development stage (42 to 56 DAS).

The Effectiveness of Using Two Sustainable Night Heating Modes on Greenhouse Cultivation

The main purpose of this paper is to study the efficiency of the deployment in Tunisia of the Ground Source Heat Pump (GSHP) system and of a solar air heater with latent storage (SAHLS) for heating mode application. A pilot GSHP system using conic ground heat exchanger and a SAHLS were installed and experimented in the Research and Technology Center of Energy (CRTEn), Borj Cédria, northern Tunisia. The status of geothermal and the solar air collector energies and their utilization are pointed out, the evaluation of both systems is examined for air heating. Their effect in the growth rate and yield of tomato are also studied. The main results show that the SAHLS gives the appropriate microclimate for plants under greenhouse in comparison with GSHP: high night temperature and low relative humidity. This leads to earliness of 2 weeks and a good quality and quantity of fruits represented by high relative growth rate, high phenolic compounds and a high quantity of marketable fruits.