Decreased Water Loss Research Articles

Stomatal cavity modulates the gas exchange of Sorghum bicolor (L.) Moench. grown under different water levels.

This work aimed to evaluate the effects of lower water levels on leaf intercellular spaces and to assess their relations with the gas exchange, anatomy, and growth of Sorghum bicolor. Experiments were conducted in a greenhouse, in which plants were subjected to three water conditions (ten replicates, n = 30): well-irrigated, decreased irrigation, and limited irrigation. Lower water levels had no significant effect on the growth of S. bicolor but increased the biomass of the roots. Moreover, the number of leaves, leaf area, and leaf size as well as the chlorophyll content were not affected by lower water levels, and no significant changes were detected for whole plant photosynthesis, transpiration, or stomatal conductance. The water content of the plants and the water potential remained unchanged. However, compared with other treatments, the decreased irrigation decreased water loss and increased the water retention. Lower water levels increased the intercellular CO2 percentage, mesophyll area, and proportion of stomatal cavities and promoted minor changes in leaf tissue and stomatal traits. The increased stomatal cavities provided higher CO2 uptake and prevented excessive water loss. Thus, modifications to the intercellular spaces promoted conditions to avoid excessive water loss while concurrently improving CO2 uptake, which are important traits for drought-tolerant plants.

Genome-Wide Analysis of NF-Y Genes in Potato and Functional Identification of StNF-YC9 in Drought Tolerance.

The nuclear factor Y (NF-Y) family is comprised of transcription factors that have been implicated in multiple plant biological processes. However, little is known about this family in potato. In the present study, a total of 41 StNF-Y genes were identified in the potato genome. In addition, the phylogenetic, gene structure, motif, and chromosomal location of this family were analyzed. The tissue expression profiles based on RNA-seq data showed that 27 StNF-Y genes had tissue-specific expression, while the remaining 14 had low expression in all tissues. Publicly available transcriptomics data from various abiotic stresses revealed several stress-responsive StNF-Y genes, which were further verified via quantitative real-time polymerase chain reaction experiments. Furthermore, the StNF-YC9 gene was highly induced by dehydration and drought treatments. StNF-YC9 protein was mainly localized in the nucleus and cytoplasmic membrane. Overexpressing StNF-YC9 potato lines (OxStNF-YC9) had significantly increased in root length and exhibited stronger stomatal closure in potato treated by polyethylene-glycol and abscisic acid. In addition, OxStNF-YC9 lines had higher photosynthetic rates and decreased water loss under short-term drought stress compared to wild-type plants. During long-term drought stress, OxStNF-YC9 lines had higher proline levels, lower malondialdehyde content, and increased activity of several antioxidant enzymes, including superoxide dismutase, catalase, and peroxidase. This study increased our understanding of the StNF-Y gene and suggested that StNF-YC9 played an important role in drought tolerance by increased the photosynthesis rate, antioxidant enzyme activity, and proline accumulation coupled to lowered malondialdehyde accumulation in potato.

Machine learning models perform better than traditional empirical models for stomatal conductance when applied to multiple tree species across different forest biomes

Stomatal closure decreases water loss and is one of the main mechanisms that trees can use to mitigate drought-induced physiological stress. The adaptability of trees to drought is likely to be of increasing importance as climate changes occur around the world. Modelling stomatal regulation can help improve our understanding of how forests respond to their environment. Traditionally, empirical models have been used to model stomatal responses, however these models cannot always capture nonlinear responses and their parameters are often difficult to measure. In this study various machine learning (ML) models were able to capture stomatal responses of multiple tree species. We showed that ML can be a useful tool for predicting stomatal response based on climate variables and species traits. A random forest model performed the best with an R2 of 75 %, compared to the empirical Ball-Berry stomatal conductance model (BWB) (R2 = 41 %). In this study, the use of a combined dataset consisting out of data from multiple studies were successfully used, showcasing the use of data across studies. This also allowed for an ML model to be trained on 36 tree species from 5 forest biomes, from measurements taken across 6 continents, instead of being limited to one species, increasing the versatility of the model. The importance of species-specific stomatal responses was highlighted, with the drought strategies used by plants significantly influencing stomatal responses and predictions. ML models were able to capture these trends parsimoniously without prior knowledge of the underlying physiology of the tree species. The quality of combined datasets are however still not desirable, and long-term data collection using standardized measuring protocols are required to increase the strength of ML models. Data taken across different climatic regions and vegetation types can also help improve the adaptability of ML models. Regardless of limitations on data accessibility, ML shows promise in modelling plant responses to changes in climate. Focus on the use of ML together with traditional models can help give further insight into various ecological mechanisms.

Physiological and Molecular Responses of Six Apple Rootstocks to Osmotic Stress.

The growth and productivity of several apple rootstocks have been evaluated in various previous studies. However, limited information is available on their tolerance to osmotic stress. In the present study, the physiological and molecular responses as well as abscisic acid (ABA) levels were assessed in six apple rootstocks (M26, V3, G41, G935, B9 and B118) osmotically stressed with polyethylene glycol (PEG, 30%) application under greenhouse conditions. Our results showed that V3, G41, G935 and B9 had higher relative water content (RWC), and lower electrolyte leakage (EL) under stress conditions compared to M26 and B118. Additionally, water use efficiency (WUE) was higher in V3, G41 and B9 than M26, which might be partially due to the lower transpiration rate in these tolerant rootstocks. V3, G41 and B9 rootstocks also displayed high endogenous ABA levels which was combined with a reduction in stomatal conductance and decreased water loss. At the transcriptional level, genes involved in ABA-dependent and ABA-independent pathways, e.g., SnRK, DREB, ERD and MYC2, showed higher expression in V3, G41, G935 and B9 rootstocks compared to M26 in response to stress. In contrast, WRKY29 was down-regulated in response to stress in the tolerant rootstocks, and its expression was negatively correlated with ABA content and stomatal closure. Overall, the findings of this study showed that B9, V3 and G41 displayed better osmotic stress tolerance followed by G935 then M26 and B118 rootstocks.

Postharvest application of partitioned plant extracts from Sinaloa, Mexico for controlling papaya pathogenic fungus Colletotrichum gloeosporioides

Anthracnose compromises papaya production and is caused by the fungus Colletotrichum gloeosporioides. New natural alternatives to synthetic fungicides are necessary to control anthracnose due to health and environmental concerns. In this regard, extracts of plants from Sinaloa, Mexico, have shown activity against molds and yeasts with medical and agricultural importance; however, their protective effect on papaya fruit infected with C. gloeosporioides is still unknown. This study aimed to assess the in vitro and in vivo antifungal activities of crude methanol extracts (ME) from nine plants from Sinaloa, Mexico, and their semi-purified fractions. In vitro assays showed that C. gloeosporioides was inhibited by 7 out the 16 extracts assessed; Psidium sartorianum (pulp), Echeveria kimnachii (leaf), and Vitex mollis (VM) (pulp) had the highest antifungal activity and the lowest toxicity against Artemia salina. When these extracts were fractionated, the activity increased. Hexane (HF-VM) and ethyl acetate (EAF-VM) fractions of V. mollis were the most effective fractions (MEF), with the lowest minimum inhibitory concentration (MIC) (20 and 30 mg/mL, respectively). The in vivo results showed that HF-VM at 40 mg/mL (HF40) was the best to delay the apparition and development of anthracnose symptoms. Coumarins, alkaloids and terpenes were detected on this fraction by tube assays or thin layer chromatography (TLC). Moreover, this treatment decreased water loss and did not affect any of the quality parameters assessed. Therefore, HF40 is a natural alternative to thiabendazole (TBZ) in the protection of papaya fruit against anthracnose.

The effect of deficit irrigation on yield and water use efficiency of lentil (Lens culinaris Medik.).

کم‌آبیاری یکی از گزینه‌های ایده‌آل برای کاهش تلفات آب و به تبع آن بهینه‌سازی کارایی مصرف آب در مناطق خشک است. به همین منظور، آزمایشی به صورت کرت‌های خرد شده در قالب طرح بلوک‌های کامل تصادفی در 4 تکرار در مزرعه تحقیقاتی مجتمع آموزش عالی سراوان انجام شد. فاکتور اصلی شامل چهار سطح ‌آبیاری (شامل 120، 100، 80 و 60 درصد) و فاکتور فرعی دو توده عدس (بلوچستان و کردستان) بود. به طور کلی، نتایج نشان داد که اثر کم‌آبیاری بر عملکرد دانه، عملکرد بیولوژیک، شاخص برداشت، تعداد غلاف در بوته، تعداد دانه در بوته و کارایی مصرف آب معنی‌دار بود. صرف‌نظر از توده عدس، با افزایش میزان مصرف آب، عملکرد افزایش پیدا کرد اما این افزایش در سطح 120 درصد نسبت به شاهد معنی‌دار نبود که این امر منجر به کاهش کارایی مصرف آب در تیمار 120 درصد گردید. تیمار 80 درصد با10 درصد کاهش عملکرد نسبت به تیمار شاهد (100 درصد)، دارای بیشترین کارایی مصرف اب بود. همچنین، بیشترین شاخص برداشت در تیمار 80 درصد (0.24) و توده بلوچستان بدست آمد. عملکرد بیولوژیک توده بلوچستان در تیمار 80 درصد نسبت به تیمار شاهد، 27 درصد کاهش یافت که در نهایت منجر به افزایش شاخص برداشت شد. بنابراین، با توجه به اینکه منطقه مورد نظر جزء اقلیم‌های خشک محسوب می‌شود می‌توان با 20 درصد کاهش آب آبیاری از منابع محدود آب حفاظت کرد.

A co-opted steroid synthesis gene, maintained in sorghum but not maize, is associated with a divergence in leaf wax chemistry

Virtually all land plants are coated in a cuticle, a waxy polyester that prevents nonstomatal water loss and is important for heat and drought tolerance. Here, we describe a likely genetic basis for a divergence in cuticular wax chemistry between Sorghum bicolor, a drought tolerant crop widely cultivated in hot climates, and its close relative Zea mays (maize). Combining chemical analyses, heterologous expression, and comparative genomics, we reveal that: 1) sorghum and maize leaf waxes are similar at the juvenile stage but, after the juvenile-to-adult transition, sorghum leaf waxes are rich in triterpenoids that are absent from maize; 2) biosynthesis of the majority of sorghum leaf triterpenoids is mediated by a gene that maize and sorghum both inherited from a common ancestor but that is only functionally maintained in sorghum; and 3) sorghum leaf triterpenoids accumulate in a spatial pattern that was previously shown to strengthen the cuticle and decrease water loss at high temperatures. These findings uncover the possibility for resurrection of a cuticular triterpenoid-synthesizing gene in maize that could create a more heat-tolerant water barrier on the plant's leaf surfaces. They also provide a fundamental understanding of sorghum leaf waxes that will inform efforts to divert surface carbon to intracellular storage for bioenergy and bioproduct innovations.

Hydrological Properties of a Clay Loam Soil as Affected by Biochar Application in a Pot Experiment

Improving soil-water relations by amending soil with biochar might play a significant role in increasing water availability for agricultural crops as well as decreasing water loss through drainage or runoff. While the effects of biochar on the hydrological properties on coarse-textured soils are generally positive and well-documented in the literature, studies on biochar effects on fine-textured soils are rather scarce and even contradictory. Therefore, the aim of this paper was to investigate the impact of biochar on the bulk density, water retention curve (together with several water capacitive indicators) and water infiltration rate in a clay loam soil. A pot experiment was carried out under lab conditions in which biochar was mixed with soil at rates of 0 (B0 or control), 2, 4, 6, 8 and 10% dw (B2, B4, B6, B8 and B10, respectively). Water retention of soil–biochar mixtures at different matrix potentials was determined using a pressure plate apparatus. From these measurements, a series of capacitive indicators was derived and the fitting of the van Genuchten model was also performed. Water infiltration into soil–biochar mixtures was measured by means of a mini-disk infiltrometer and the obtained data were analyzed both directly and by fitting the Philip’s model. Biochar significantly affected the considered soil properties. As the biochar rate increased, the bulk density decreased and water retention increased (B6, B8 and B10 > B2, B4 and B0), while the infiltration rate decreased (B0 > B2, B4, B6, B8 and B10). Although the experiment was performed on sieved and repacked soil samples under lab conditions, the results confirmed that biochar has the potential to increase plant-available water, while possibly reducing drainage water in a clay loam soil by lowering the infiltration rate.

Modeling and optimizing the changes in physical and biochemical properties of table grapes in response to natural zeolite treatment

The Response Surface Methodology (RSM) was used to establish a predictive model for the effects of natural zeolite at different concentration and different storage times, as independent variables, on shelf life, physical and chemical properties, quality parameters and phytochemicals compounds of table grapes. The response surface models (RS model) had satisfactory R2 and Adj.R2 and models had non-significant lack of fit (P > 0.05). The parameters of the RS model had a good predictive performance and can be considered validated. The results demonstrated that natural zeolite is able to significantly improve the table grape tissue firmness, enhance different phytochemicals and antioxidants, and decrease water loss, electrolyte leakage, malondialdehyde production and decay extension rates. Treated fruit had a higher superoxide dismutase, ascorbate peroxidase and total antioxidant activity and phenolics, flavonoids and carotenoids contents. Using desirability function method treatment of table grapes with zeolite at 6% and storage for 60 days was found to be the optimized condition.

Effects of immersion freezing with coolant on the quality of grouper (♀Epinephelus fuscoguttatus ×♂ Epinephelus lanceolatus) during frozen storage

ABSTRACT In this study, we evaluated the effects of immersion freezing (IF) with coolant and air freezing (AF) techniques with different storage temperature (−18°C and −30°C) on the quality of groupers following frozen storage. Water loss rate, total volatile basic nitrogen, and the K-value, were positively correlated with storage time. The pH first decreased and then increased. Destruction of the muscle fiber structure led to changes in grouper texture characteristics including hardness, cohesiveness, springiness, and chewiness. IF-30°C samples retained the highest quality after frozen storage, followed by IF-18°C samples and AF-18°C samples. Immersion freezing limited protein denaturation, decreased water loss, and contributed to the formation of uniformly distributed ice crystals, decreasing microstructure damage. Immersion freezing is a promising technique for preserving the quality of groupers, and the immersion coolant (propylene glycol, oligosaccharides and salts) used in this study has potential applications in the grouper processing industry.

Effect of prunes on organoleptic and technological properties of minced meat

At the present time, the search for natural ingredients that improve characteristics of minced meat products, and reduce the amount of synthetic food additives is going on. Plant components are the most popular. Most often they are recommended to be added in the powder form. This helps to improve technological properties of minced systems, as well as reduce the cost of products. In the article the possibility of applying prunes in the composition of minced beef is considered. The effects of prunes on an increase in water-holding capacity of minced meat to 54.4 % in a sample with 20% prune content, a decrease in water loss during 10 days of storage in a frozen state by 4.4 % in the same sample, an increase in the yield of finished products during thermal processing by 8.9 % are shown. It was found out that the color of finished products is within the acceptable range when decreasing the proportion of sodium nitrite to 0.003 % in the recipe, and even at its absence.

EFFECT OF ESSENTIAL OILS ON STORAGE AND KEEPING QUALITY OF GLADIOLUS CUT FLOWERS

A trial was consummated at Postharvest Lab. of Floriculture Res. Dept. Hort. Res. Inst. ARC, Giza, Egypt during 2019 and 2020 seasons to study the influence of essential oils of clove and sage oil in two experiments as preservative solutions, or a spray treatments as well as under long term of storage at low temperatures for three periods on quality and vase life of cut inflorescences of Gladiolus grandiflorus. In the first experiment five holding solutions included, clove oil at 1 and 2 mg/l + 20 g/l sucrose (suc.), sage oil at 1and 2 mg/l + 20 g/l sucrose (suc.), 8-hydroxyquinoline citrate (8-HQC) at 200 pm + 20 g/l sucrose (suc.) and control (distilled water D.W.) were used. In second experiment that used essential oils as spray treatments. The obtained results from the two experiments indicated that, the flowers hold in the preservative solution of sucrose + clove oil (1 mg/l) significantly prolonged vase life, increased flowers fresh weight (%) and water uptake (g), dry weight (%), percentage of opening floret (%) and decreased water loss(g), bacterial counts in the vase solution. Essential oils had a positive effect on total sugar concentrations, level of total indoles and total phenols and total chlorophyll contents of cut flowers. Essential oils as an alternative substitute to chemical compounds had an excellent effect on cut flowers also because of their antimicrobial activities and environmental friendly nature.

Effect of three air supply modes on water evaporation process in limited space of frost-free refrigerator

• Air forced convection in frost-free refrigerator accelerates water evaporation. • The numerical results are in good agreement with experimental results. • The water evaporation rate during on cycle is 20 times of that during off cycle. • Effect of three air supply modes on water evaporation process were analyzed. • The water evaporation rate of annularly blowing air supply mode is the least. The air forced convection is utilized to cool foods in frost-free refrigerator, and it offers uniform temperature field and the fast cooling rate. But the air forced convection also accelerates the water evaporation from foods surface, which leads to foods dehydration. Numerical model of water evaporation process inside refrigerating compartment was validated by experimental results including the evaporated water mass, air temperature and relative humidity during compressor on /off cycle. The air supply modes have effects on velocity and temperature fields inside refrigerating compartment, and three air supply modes were compared: annularly blowing air (ABA) supply, upward blowing air (UBA) supply and forward blowing air (FBA) supply modes. The results show that the water evaporation rate during compressor-on cycle is 20 times of that during compressor-off cycle. The effect of air velocity on water evaporation process is greater than that of vapor partial pressure difference. The water evaporation rate for FBA supply mode is the largest due to its highest air velocity. The water evaporation rate of A B A supply mode is the least because of both its smaller air velocity and vapor partial pressure difference, and it is the best mode to decrease water loss.

The effects of foliar-applied manganese on major cell wall polysaccharide fractions and soluble sugar composition of cucumber leaves

Increasing evidence shows that micronutrients can induce changes in cell wall (CW) properties in plants. A detailed knowledge of these changes will contribute to understand the beneficial and detrimental impacts of trace elements on plant development and defence. In the present work, the influence of foliar spray of manganese (Mn) on the composition of CW polysaccharides and soluble sugars was investigated in cucumber leaves using spectrophotometric and chromatographic techniques. Cucumber seedlings were hydroponically cultured under controlled situations for 21 days. At the two-leaf stage, the above facade of cucumber leaves was fertilized with MnSO4 solutions at various dosages (1.8, 4.5 and 7.2 mM). Results showed that the foliar Mn spray decreased the galacturonic acid (GalA) content, while it increased the degree-of-methyl-esterification (DM) of pectin. The amounts of fucose, arabinose and galactose diminished upon Mn application. The contents of rhamnose and xylose decreased or did not change by Mn treatment. The glucose level enhanced at low concentration of Mn (1.8 mM), but it decreased at medium and high concentrations of Mn (4.5 and 7.2 mM). The increase of mannose content was significant only at medium concentration of Mn. Overall, the amount of total hemicellulose increased at 1.8 mM concentration of Mn, while a decrease was observed at 4.5 and 7.2 mM concentrations of Mn. The cellulose content decreased at low and high concentrations of Mn, although it remained unchanged at medium concentration of Mn. Generally, the total contents of CW polysaccharides increased at low concentration of Mn, but they decreased at the higher concentrations of Mn. Such changes can be important in plant resistance to environmental stresses via reduction of permeability against fungal pathogens and decrease of water loss from tissues under stresses such as drought and salinity.

The Arabidopsis F-box protein FOF2 regulates ABA-mediated seed germination and drought tolerance

The phytohormone abscisic acid (ABA) plays a crucial role at various plant developmental stages, including seed germination and seedling development, and regulates stomatal aperture in response to drought. However, the underlying mechanisms are not well understood. Here, we showed that F-BOX OF FLOWERING 2 (FOF2) is induced by ABA and drought stress. Overexpression of FOF2 led to reduced ABA sensitivity during seed germination and early seedling development, whereas the fof2 mutant exhibited increased sensitivity to ABA. Molecular and genetic analyses revealed that FOF2 negatively affected ABA-mediated seed germination and early seedling development partially by repressing the expression of the ABA-signaling genes ABI3 and ABI5. Additionally, we found that FOF2-overexpressing plants exhibited increased ABA contents, enhanced ABA sensitivity during stomatal closure, and decreased water loss, thereby improving tolerance to drought stress, in contrast to the fof2 mutant. Consistent with a higher ABA content and enhanced drought tolerance, the expression of ABA- and drought-induced genes and the ABA-biosynthesis gene NCED3 was upregulated in the FOF2-overexpressing plants but downregulated in fof2 mutant in response to drought stress. Taken together, our findings revealed that FOF2 plays an important negative role in ABA-mediated seed germination and early seedling development, as well as a positive role in ABA-mediated drought tolerance.

Effect of surface and drip irrigation levels on growth, yield, nutrient uptake and water productivity of maize : A review

Maize (Zea mays L.) a miracle crop, grown over a wide range of climatic conditions in semi arid and sub tropics for food and fodder. Under irrigated condition, it has high production potential when compared to any other cereal crops. Water scarcity and soil infertility are two critical factors limiting maize grain yield over most regions. The limited water resources in the area and the cost of pumping irrigation water are the most important factors that force many farmers to reduce irrigation in deficit areas. The present furrow and flooding method of irrigation followed in maize are having low application and irrigation efficiency which in turn permitting more chances for loss of water. Therefore, switching over to modern methods of irrigation like drip irrigation is necessary to decrease water losses due to conveyance and evaporation. Therefore, effective water management for agricultural production in water scarce regions requires application of innovative and sustainable approaches. With the present context, nowadays drip irrigation is gaining a lot of importance due to its higher irrigation efficiency (90%) and also will curse down the drawbacks of the present methods. Hence, optimization of irrigation scheduling irrigation using drip system which reduces the water application losses without reducing the yield is of prime concern as both deficit and excess water supplies could affect maize growth in the tropical climate.

The Sweetpotato BTB-TAZ Protein Gene, IbBT4, Enhances Drought Tolerance in Transgenic Arabidopsis.

BTB-TAZ (BT)-domain proteins regulate plant development and pathogen defense. However, their roles in resistance to abiotic stresses remain largely unknown. In this study, we found that the sweetpotato BT protein-encoding gene IbBT4 significantly enhanced the drought tolerance of Arabidopsis. IbBT4 expression was induced by PEG6000, H2O2 and brassinosteroids (BRs). The IbBT4-overexpressing Arabidopsis seeds presented higher germination rates and longer roots in comparison with those of WT under 200 mM mannitol stress. Under drought stress the transgenic Arabidopsis plants exhibited significantly increased survival rates and BR and proline contents and decreased water loss rates, MDA content and reactive oxygen species (ROS) levels. IbBT4 overexpression upregulated the BR signaling pathway and proline biosynthesis genes and activated the ROS-scavenging system under drought stress. Yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) assays revealed that the IbBT4 protein interacts with BR-ENHANCED EXPRESSION 2 (BEE2). Taken together, these results indicate that the IbBT4 gene provides drought tolerance by enhancing both the BR signaling pathway and proline biosynthesis and further activating the ROS-scavenging system in transgenic Arabidopsis.

Effects of rumen-protected betaine supplementation on meat quality and the composition of fatty and amino acids in growing lambs

Rumen-protected betaine (RPB) can enhance betaine absorption in the small intestine of ruminants, while betaine can alter fat distribution and has the potential to affect the meat quality of livestock. Hence, we hypothesized that RPB might also affect the meat quality of lambs. Sixty male Hu sheep of similar weight (30.47 ± 2.04 kg) were selected and randomly subjected to five different treatments. The sheep were fed a control diet (control treatment, CTL); 1.1 g/day unprotected-betaine supplemented diet (UPB); or doses of 1.1 g/day (low RPB treatment; L-PB), 2.2 g/day (middle RPB treatment; M-PB) or 3.3 g/day (high RPB treatment; H-PB) RPB-supplemented diet for 70 days. Slaughter performance, meat quality, fatty acid and amino acid content in the longissimus dorsi (LD) muscle, shoulder muscle (SM) and gluteus muscle (GM) were measured. Compared with CTL, betaine (including UPB and RPB) supplementation increased the average daily weight gain (ADG) (P < 0.05) and average daily feed intake (P < 0.01) of lambs. Rumen-protected betaine increased ADG (P < 0.05) compared with UPB. With increasing RPB doses, the eye muscle area of the lambs linearly increased (P < 0.05). Compared with CTL, betaine supplementation decreased water loss (P < 0.05) in SM and increased pH24 in the SM (P < 0.05) and GM (P < 0.05). Compared with UPB, RPB decreased water loss in the GM (P < 0.01), decreased shear force (P < 0.05) in the LD and SM and increased the pH of the meat 24 h after slaughter (pH24). With increasing RPB doses, the shear force and b* value in the LD linearly decreased (P < 0.05), and the pH24 of the meat quadratically increased (P < 0.05). Compared with CTL, betaine supplementation increased the polyunsaturated fatty acid in the GM (P < 0.05). Compared with UPB, RPB supplementation decreased the saturated fatty acid (SFA) content in the LD (P < 0.05) and increased the unsaturated fatty acids (UFA), mono-unsaturated fatty acids and UFA/SFA ratio in the LD (P < 0.05). Compared with CTL, the content of histidine in the LD increased with betaine supplementation. Compared with UPB, RPB supplementation increased the content of total free amino acids and flavor amino acids in the LD of lambs (P < 0.05). With increasing RPB, the isoleucine and phenylalanine contents in the LD linearly increased (P < 0.05). Overall, the data collected indicated that the meat quality of lambs (especially in the LD) improved as a result of betaine supplementation, and RPB showed better effects than those of UPB.

Differential response of cuticular wax and photosynthetic capacity by glaucous and non-glaucous wheat cultivars under mild and severe droughts

Cuticular wax is known to play an important role in non-stomatal transpiration. However, support is lacking regarding the waxy phenotype for wheat breeding against drought. In this study, four wheat cultivars with different wax phenotypes (glaucous and non-glaucous types) were used to evaluate their responses to drought stress and impact on photosynthetic capability of wheat. Xinong 291 and HY 2912, with the glaucous trait, demonstrated higher diketone ratios and contents compared with Pubing 201 and Jinmai 47, which are the non-glaucous type. The cultivars HY 2912 and Jinmai 47 had 35% higher biomass than did Xinong 291 and Pubing 201 under severe drought condition. HY 2912 exhibited the highest wax load with or without drought stress. Jinmai 47 showed the highest ratio of alkane content. Among glaucous cultivars, drought-resistant HY 2912 may promote growth by decreasing water loss, increasing the diketone content, increasing the total wax load, and maintaining mesophyll and stomatal conductance. Among non-glaucous cultivars, drought-resistant Jinmai 47 may enhance growth via stomatal closure and increased mesophyll conductance and alkane ratios. The glaucous trait was not always associated with drought resistance, and correlation analysis revealed that the diketone ratio was positively related to the intercellular CO2 concentration. These results suggest that the mechanism of drought resistance in wheat is systematically regulated by wax alteration, stomatal conductance and mesophyll conductance. Therefore, wax content and composition as well as mesophyll and stomatal regulation should be considered in the breeding and selection of drought-resistant wheat cultivars.

Comparative Study of Pressure Control Modes Impact on Water Distribution System Performance

Four pressure control modes (CMs) for water distribution systems, which are: 1) fixed control (FC); 2) time-based control (TBC); 3) reactive control (RC); and 4) ideal predictive control (IC), are compared based on their performance in terms of reduction in i) leakage rate and ii) pressure fluctuation intensity. The comparison is performed for three real Canadian distribution networks. Pressure fluctuation intensity, pressure variations distribution, and leakage rate reduction are the performance indices computed for each CM. The impact of differences in elevation and pipe roughness are also assessed. It is shown that in all cases, the active CMs (IC and RC) are more effective than the passive ones (TBC and FC). A decrease in water loss and in pressure fluctuation intensity was obtained when adopting CMs other than FC. The highest benefits were provided by IC, followed by RC and TBC (e.g. reduction in leakage rates lower than 4% for TBC and up to 26% for IC and RC, compared with the fixed control mode). The benefits of active CMs are higher when the difference in nodes elevation is lower and when the pipe roughness is greater, both cases amplifying the relative impact of pipe friction on the pressure delivered to each node in the system.