Display omitted
•Steam cooking (SC) resulted in higher T1 and T2 values than boiling (BC).•SC resulted in higher proton mobility and density in meat than BC.•The difference of cooking loss between SC ...and BC mainly occurred in 60–80 °C.•Muscle shrinkage explained the water status evolution during cooking process.•Actin denaturation affected the cooking loss more significantly than did myosin.
A two-dimensional low-field nuclear magnetic resonance (LF-NMR) T1-T2 relaxation technique was developed to contrast the water status evolution during different cooking procedures (steam and boiling cooking). Meat quality, water distribution, microstructure and protein properties were determined. The results showed that steamed meats had lower cooking loss and shear force, but higher redness, proton relaxation intensity (T1 and T2) and proton density than boiled meats. The differences in water distribution between the two cooking procedures appeared at approximately 40 °C, with acceleration at 60 °C, and the most remarkable difference was shown at 80 °C. Boiling resulted in more damage to muscle structure and greater protein denaturation than steam cooking. Meanwhile, α-helixes and β-turns increased, but β-sheets and random coils decreased in steamed meats compared with boiled meats. Changes in microstructural and protein properties were closely associated with water status evolution in cooked meat during cooking.
Many quality attributes of food products are influenced by the water status and the microstructure. Low-field nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) methods are applied ...to non-destructively monitor the water status and structure of food. The aim of this study is to investigate the water status and distribution inside broccoli tissues and the effects of hot-air drying on the water status by using NMR and MRI methods. Transverse relaxation times (T2) provide the information of water status and water distribution. Results show that three water fractions with different T2 relaxation times were detected inside broccoli, which corresponded to different cell compartments. Proton weighted imaging could monitor the spatial distribution of water. Image analysis indicates that the water distribution inside broccoli was heterogeneous and the water content reduced from the stalk to the buds. During hot-air drying experiments, different drying kinetics were observed in the florets and stalks, which were related to their different structures. In addition, a detection limit of the moisture content was calculated for LF-NMR (about 11.35%). The results of this study show that the low-field NMR and MRI methods can precisely provide the quantitative information of water status inside food materials, and can be used to investigate the effects of food processing on product quality. The method provided in this study can be used to monitor changes of water status and distribution in a sample non-destructively during drying process.
Display omitted
•A new non-destructive approach is applied to investigate water status in broccoli.•T2 studies with paramagnetic Mn2+ provide the information of water status and water distribution.•Spatial distribution of water is visualized by proton weighted imaging.•Effects of hot-air drying on water status and structure of broccoli were observed.•Detect limit of moisture content by low-field NMR method was calculated.
Microplastics may enter the soil in a wide range of shapes and polymers. However, little is known about the effects that microplastics of different shapes, polymers, and concentration may have on ...soil properties and plant performance. To address this, we selected 12 microplastics representing different shapes (fibers, films, foams, and fragments) and polymers, and mixed them each with soil at a concentration of 0.1, 0.2, 0.3, and 0.4%. A phytometer (
) grew in each pot during 4 weeks. Shoot, root mass, soil aggregation, and microbial activity were measured. All shapes increased plant biomass. Shoot mass increased by ∼27% with fibers, ∼60% with films, ∼45% with foams, and by ∼54% with fragments, as fibers hold water in the soil for longer, films decrease soil bulk density, and foams and fragments can increase soil aeration and macroporosity, which overall promote plant performance. By contrast, all shapes decreased soil aggregation by ∼25% as microplastics may introduce fracture points into aggregates and due to potential negative effects on soil biota. The latter may also explain the decrease in microbial activity with, for example, polyethylene films. Our findings show that shape, polymer type, and concentration are key properties when studying microplastic effects on terrestrial systems.
Chloride (Cl−) is traditionally categorized as an antagonist of nitrate (NO3−) because Cl− hinders plant NO3− transport and accumulation. However, we have recently defined Cl− as a beneficial ...macronutrient for higher plants, due to specific functions that lead to more efficient use of water, nitrogen (N) and CO2 under optimal N and water supply. When accumulated in leaves at macronutrient levels, Cl− promotes growth through osmotic, physiological, metabolic, anatomical and cellular changes that improve plant performance under optimal NO3− nutrition. Nitrate over-fertilization in agriculture can adversely affect crop yield and nature, while its deficiency limits plant growth. To study the relationship between Cl− nutrition and NO3− availability, we have characterized different physiological responses such as growth and yield, N-use efficiency, water status, photosynthesis, leaf anatomy, pigments and antioxidants in tomato plants treated with or without 5 mM Cl− salts and increasing NO3− treatments (3–15 mM). First, we have demonstrated that 5 mM Cl− application can reduce the use of NO3− in the nutrient solution by up to half without detriment to plant growth and yield in tomato and other horticultural plants. Second, Cl− application reduced stress symptoms and improved plant growth under low-NO3− conditions. The Cl−-dependent resistance to low-N stress resulted from: more efficient use of the available NO3−; improved plant osmotic and water status regulation; improved stomatal conductance and photosynthetic rate; and better antioxidant response. We proposed that beneficial Cl− levels increase the crop ability to grow better with lower NO3− requirements and withstand N deficiency, promoting a more sustainable and resilient agriculture.
•This study focuses on the study of the physiological responses of plants to chloride and nitrate nutrition.•Chloride can partially replace nitrate application maintaining growth and yield in several horticultural plants.•Symptoms of low nitrogen stress are alleviated by chloride nutrition at macronutrient levels.•The better chloride-dependent water status sustains plant growth and photosynthesis under low nitrogen stress conditions.
•Alternate wetting and drying (AWD) treatments of increasing soil drying were tested.•Yields were similar to the continuously flooded control even with 12 days of drying.•Water was available and ...roots were present at 25–35 cm soil depth.•AWD-Safe (2 days of drying) did not decrease grain As concentration.•Grain As concentration was decreased in the two driest AWD treatments.
Continuously flooded rice systems are a major contributor to global rice production and food security. Allowing the soil to dry periodically during the growing season (such as with alternate wetting and drying irrigation - AWD) has been shown to decrease methane emissions, water usage, and heavy metal accumulation in rice grain. However, the effects of AWD on rice yields are variable and not well understood. A two-year study was established to quantify the impacts of a range of treatments differing in AWD severity (degree of soil drying between flooding events) on yield (as well as factors that may affect yields), soil hydrology in the soil profile, and grain arsenic (As) concentrations relative to a continuously flooded control (CF). Three AWD treatments of increasing severity were imposed between full canopy cover (around 45 days after sowing) and 50% heading: AWD-Safe (field was reflooded when the perched water table reached 15 cm below the soil surface) and AWD35 and AWD25 (field was reflooded when the soil volumetric water content at 0–15 cm depth reached 35% and 25%, respectively). During the drying periods, the 0–15 cm soil layer in the AWD-Safe remained saturated, whereas in AWD35 and AWD25 the soil dried to the desired volumetric water contents. In contrast, soil moisture at 25–35 cm below the soil surface was similar across all treatments. Yield was not reduced in any of the AWD treatments, compared to the CF control. There were no consistent differences in yield components, 13C discrimination, and N dynamics. Results suggest that the availability of water and the presence of roots at the 25–35 cm soil depth during the drying periods ensured that the crop did not suffer drought stress and thus yields were maintained. Grain As concentration in the AWD-Safe treatment was similar to that in the CF control but decreased by 56–68% in AWD35 and AWD25. AWD-Safe is often promoted as a means of practicing AWD without reducing yields; however, in this study this practice did not reduce grain As concentration because the soil did not reach an unsaturated state. These findings demonstrate that knowledge of surface and subsurface hydrology, and the root system are important for understanding the potential of AWD.
Abstract
Background and Aims
Previous laboratory studies have suggested selection for root hair traits in future crop breeding to improve resource use efficiency and stress tolerance. However, data ...on the interplay between root hairs and open-field systems, under contrasting soils and climate conditions, are limited. As such, this study aims to experimentally elucidate some of the impacts that root hairs have on plant performance on a field scale.
Methods
A field experiment was set up in Scotland for two consecutive years, under contrasting climate conditions and different soil textures (i.e. clay loam vs. sandy loam). Five barley (Hordeum vulgare) genotypes exhibiting variation in root hair length and density were used in the study. Root hair length, density and rhizosheath weight were measured at several growth stages, as well as shoot biomass, plant water status, shoot phosphorus (P) accumulation and grain yield.
Key Results
Measurements of root hair density, length and its correlation with rhizosheath weight highlighted trait robustness in the field under variable environmental conditions, although significant variations were found between soil textures as the growing season progressed. Root hairs did not confer a notable advantage to barley under optimal conditions, but under soil water deficit root hairs enhanced plant water status and stress tolerance resulting in a less negative leaf water potential and lower leaf abscisic acid concentration, while promoting shoot P accumulation. Furthermore, the presence of root hairs did not decrease yield under optimal conditions, while root hairs enhanced yield stability under drought.
Conclusions
Selecting for beneficial root hair traits can enhance yield stability without diminishing yield potential, overcoming the breeder’s dilemma of trying to simultaneously enhance both productivity and resilience. Therefore, the maintenance or enhancement of root hairs can represent a key trait for breeding the next generation of crops for improved drought tolerance in relation to climate change.
The grapevine is one of the most important edible fruit plants cultivated worldwide, and it is highly sensitive to changes in the soil water content. We studied the total carbon and nitrogen contents ...and stable isotope compositions (C/NWSR, δ13CWSR and δ15NWSR values) of the solid residues obtained by freeze-drying wines produced from two white grapevine cultivars (Vitis vinifera L. cv Chasselas and Petite Arvine) field grown under different soil water regimes while maintaining other climatic and ecopedological conditions identical. These experiments simulated the more frequent and extended climate change-induced periods of soil water shortage. The wines were from the 2009–2014 vintages, produced using the same vinification procedure. The plant water status, reflecting soil water availability, was assessed by the predawn leaf water potential (Ψpd), monitored in the field during the growing seasons. For both wine varieties, the δ13CWSR values are highly correlated with Ψpd values and record the soil water availability set by soil water holding capacity, rainfall and irrigation water supply. These relationships were the same as those observed for the carbon isotope composition of fruit sugars (i.e., must sugars) and plant water status. In Chasselas wines, the nitrogen content and δ15NWSR values decreased with soil water deficit, indicating control of the flux of soil-water soluble nutrients into plants by soil water availability. Such a correlation was not found for Petite Arvine, probably due to different N-metabolism processes in this genetically atypical cultivar. The results presented in this study confirm and generalize what was previously found for red wine (Pinot noir); the carbon isotope composition of wine solid residues is a reliable indicator of the soil and the plant water status and thus can be used to trace back local climatic conditions in the vineyard's region. In most wines (except Petite Arvine) the C/NWSR and δ15NWSR values are indicators of the origin of the nitrogen supplied to the plant's fruit (grape) that can be used to assess the N dynamics in the soil-water-plant system.
Display omitted
•Field experiment simulated soil water restriction in vineyards under climate change.•13C and 15N were analyzed in dried wines from diverse vine water status and vintages.•13C-enrichment highly correlates with vine water-stress and dryness of vintage summer.•N content and δ15N decrease with soil water deficit due to limited nutrient flow.•Vine in dried soils uses the internal organic N reserves.
•Drought stress increased AM colonization rates, which were higher in spontaneously combusted coal mine spoil.•AMF had a more beneficial effect on maize growth and nutrient uptake in spontaneously ...combusted coal mine spoil.•Maize grown in weathered coal mine spoil had higher C:P ratios and lower N:P ratios.•Maize grown in two substrates exhibited different water status in response to AMF and drought stress.•AMF played a different role in improving plant tolerance to drought depending on the substrate.
Drought stress greatly affects the growth and development of plants in coal mine spoils located in the Inner Mongolia grassland ecosystem. Arbuscular mycorrhizal fungi (AMF) can increase plant tolerance to drought. However, little is known regarding the contribution of AMF to plants that are grown in different types of coal mine spoils under drought stress. To evaluate the mycorrhizal effects on the drought tolerance of maize (Zea mays L.) grown in weathered (S1) and spontaneously combusted (S2) coal mine spoils, a greenhouse pot experiment was conducted to investigate the effects of inoculation with Rhizophagus intraradices on the growth, nutrient uptake, carbon:nitrogen:phosphorus (C:N:P) stoichiometry and water status of maize under well-watered, moderate and severe drought stress conditions. The results indicated that drought stress increased mycorrhizal colonization and decreased plant dry weights, nutrient contents, leaf moisture percentage of fresh weight (LMP), water use efficiency (WUE) and rehydration rate. A high level of AMF colonization ranging from 65 to 90% was observed, and the mean root colonization rates in S1 were lower than those in S2. In both substrates, inoculation with R. intraradices significantly improved the plant growth, P contents, LMP and WUE and decreased the C:P and N:P ratios of plants under drought stress. In addition, maize grown in S1 and S2 exhibited different wilting properties in response to AMF inoculation, and plant rehydration after drought stress occurred faster in mycorrhizal plants. The results suggested that inoculation with R. intraradices played a more positive role in improving the drought stress resistance of plants grown in S2 than those grown in S1. AMF inoculation has a beneficial effect on plant tolerance to drought and effectively facilitates the development of plants in different coal mine spoils.
Soil salinization is one of the most serious abiotic stress factors affecting plant productivity through reduction of soil water potential, decreasing the absorptive capacity of the roots for water ...and nutrients. A weighted meta-analysis was conducted to study the effects of arbuscular mycorrhizal fungi (AMF) inoculation in alleviating salt stress in C
and C
plants. We analyzed the salt stress influence on seven independent variables such as chlorophyll, leaf area, photosynthetic rate (
), stomatal conductance (
), transpiration rate (
), relative water content (RWC), and water use efficiency (WUE) on AMF inoculated plants. Responses were compared between C
and C
plants, AMF species, plant functional groups, level of salinity, and environmental conditions. Our results showed that AMF inoculated plants had a positive impact on gas exchange and water status under salt stress. The total chlorophyll contents of C
plants were higher than C
plants. However, C
plants responses regarding
, and
were more positive compared to C
plants. The increase in
mainly maintained
and it explains the increase in
and increase in
. When the two major AMF species (
and
) were considered, the effect sizes of RWC and WUE in
were lower than those in
indicating that
inoculated plants performed better under salt stress. In terms of C
and C
plant photosynthetic pathways, the effect size of C
was lower than C
plants indicating that AMF inoculation more effectively alleviated salt stress in C
compared to C
plants.
•The physiological response of winter wheat is reversible and it recovers after two weeks of re-watering.•Leaf functional indices under drought and re-watering can reflect the soil moisture ...status.•The activity of SOD and content of Pro are very sensitive to changes in soil moisture (ROC analysis, AUC=0.7-1.0).•Significant correlation exists among SOD, Pro, yield and water use efficiency.
Studying the physiological responses of winter wheat to drought is conducive to learning to utilize biological water-saving technologies, such as regulating deficit irrigation and obtaining higher water use efficiency (WUE). However, the close relationship between the trend of responses of physiological functions in wheat and changes in soil moisture merits further study. In this study, a two-season pot experiment with three levels of water deficit (45 %–75 % FC, field capacity) was established at three growth stages, based on the theory that the drought-resistant physiological functions of winter wheat could respond to regulated deficit irrigation. The goal was to explore the effects of short-term drought-re-watering on yield and WUE and the sensitivity of wheat leaf physiological indicators to reflect changes in soil moisture. The results showed that the short-term drought in different periods after the jointing period reduced the yield of winter wheat by 2.03 %–64.39 % compared with the treatment of an adequate supply of water (75 %–85 % FC). Priority should be placed on ensuring irrigation during the jointing and filling periods. Treatments that experienced drought during the heading period (55 %–75 % FC) and then recovered to 75 %–85 % FC after flowering can improve the WUE by 5 %–22 %. The physiological function of drought resistance in winter wheat leaves responds noticeably to drought and the re-watering process in the range of 45 %–85 % FC. The maximum values of the activities of superoxide dismutase (SOD) and peroxidase and the contents of malondialdehyde and proline (Pro) during drought increased by 51.9 %, 15.1 %, 40.4 %, and 157.2 %, respectively, compared with those of the control group. The activity of catalase primarily increased after rehydration, and the maximum value was 1.5-fold that of the control group. After 14 days of rehydration, the physiological index values of multiple treatments can be restored to the level of control, which proves that the physiological response within the range of 45 %–85 % FC water change is reversible. Based on the experimental data of the two seasons, the changes in activity of SOD and content of Pro more effectively reflect the changes in soil moisture than the other indicators (ROC analysis, AUC = 0.720−0.978) and have a significant correlation with yield (P < 0.05). Therefore, they can be considered as physiological reference tools to monitor the effect of irrigation and adjust its strategy.
PDF
