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1.
Doubled haploid wheat lines developed from a cross between a hard white winter wheat variety of normal starch endosperm and a waxy wheat variety were used to determine the effects of allelic variation in Wx‐1, Glu‐D1, Glu‐B3, and Pinb‐D1 loci on physiochemical properties of flour, noodle dough properties, and textural quality of cooked noodles. Milling yield, damaged starch content, protein content, and SDS sedimentation volume of flour were influenced the most by allelic composition of Pinb‐D1 loci, less by Wx‐1 loci, and least by Glu‐B3. Wheat lines carrying Pinb‐D1b or Glu‐B3h alleles exhibited higher milling yield and damaged starch content of flour than those with Pinb‐D1a and Glu‐B3d alleles. Wheat lines carrying the Pinb‐D1b allele were higher in protein content and SDS sedimentation volume than those carrying Pinb‐D1a. Mixograph water absorption was largely influenced by allelic composition of Wx‐1 loci, whereas mixograph mixing time and mixing tolerance were predominantly determined by allelic composition of Glu‐D1 loci. Amylose content and pasting properties of starch were mainly determined by allelic composition of Wx‐1 loci with little influence by allelic compositions of Glu‐D1, Glu‐B3, and Pinb‐D1 loci. Allelic composition of Wx‐1 loci contributed 53.4% of the variation in optimum water absorption of noodle dough and 26.7% of the variation in thickness of the noodle dough sheet. The variation of 7.8% in optimum water absorption of noodle dough was contributed by the allelic composition of Pinb‐D1 loci. Allelic composition of Wx‐1 loci was responsible for 73.2, 74.4, and 59.6% in the variation of hardness, springiness, and cohesiveness of cooked noodles, respectively. Cohesiveness of cooked noodles was also influenced by the allelic compositions of Glu‐B3 and Pinb‐D1 loci to a smaller extent.  相似文献   

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Calcium (Ca2+) amelioration of the plant's growth response to salinity depends on genetic factors. In this work, supplemental Ca2+ did not improve growth in Phaseolus vulgaris L. cv. Contender under high‐saline conditions and negatively affected several physiological parameters in nonsalinized plants. The response to supplemental Ca2+ was examined using plants grown in 25% modified Hoagland solution at different Na+ : Ca2+ ratios. In control plants (1 mM Ca2+; 1 mM Na+) surplus Ca2+ (4 or 10 mM) was associated with stomatal closure, decrease of hydraulic conductivity, sap flow, leaf specific dry weight, leaf K+ and leaf Mg2+ concentrations, and inhibition of CO2 assimilation. Leaf water content was enhanced, while water‐use efficiency and dry matter were unaffected during the 15 d experimental period. The Ca2+ effect was not cation‐specific since similar results were found in plants supplied with high external Mg2+ or with a combination of Ca2+ and Mg2+. Relative to control plants, salinization (50 and 100 mM NaCl) caused a decrease in dry matter, hydraulic conductivity, sap flow, leaf Mg2+ activity, and inhibition of stomatal opening and CO2 assimilation. However, NaCl (50 and 100 mM NaCl) enhanced leaf K+ concentration and water‐use efficiency. At 100 mM NaCl, leaf water content also significantly increased. Supplemental Ca2+ had no amelioration effect on the salt‐stress response of this bean cultivar. In contrast, the 50 mM–NaCl treatment improved stomatal conductance and CO2‐assimilation rate in plants exposed to the highest Ca2+ concentration (10 mM). Phaseolus vulgaris is classified as a very NaCl‐sensitive species. The similarities in the effects caused by supplemental Ca2+, supplemental Mg2+, and NaCl salinity suggest that P. vulgaris cv. Contender has a high non‐ion‐specific salt sensitivity. On the other hand, the improvement in gas‐exchange parameters in Ca2+‐supplemented plants by high NaCl could be the result of specific Na+‐triggered responses, such as an increase in the concentration of K+ in the leaves.  相似文献   

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《Cereal Chemistry》2017,94(2):251-261
The objective for this study was to investigate the effectiveness of scaled‐up infrared (IR) heating followed by tempering steps to dry freshly harvested rough rice. An industrial‐type, pilot‐scale, IR heating system designed to dry rough rice was used in this study. The heating zone of the equipment had catalytic IR emitters that provided heat energy to the sample as it was conveyed on a vibrating belt. The sample comprised freshly harvested rough rice of long‐grain pureline (Cheniere), long‐grain hybrid (6XP 756), and medium‐grain (CL 271) cultivars at initial moisture contents of 23, 23.5, and 24% wb, respectively. Samples at a loading rate of 1.61 kg/m2 were heated with IR of radiation intensity 5.55 kW/m2 for 30, 50, 90, and 180 s followed by tempering at 60°C for 4 h, at a product‐to‐emitter‐gap size of 450 mm, in one‐ and two‐pass drying operations. Control samples were gently natural air dried in an equilibrium moisture content chamber set at relative humidity of 65% and temperature of 26°C to moisture content of 12.5% wb. The effects of IR treatments followed by tempering on percentage points of moisture removed, head rice yield, energy use, rice color, and pasting characteristics were evaluated. For all cultivars, percentage point moisture removed increased with increase in IR drying duration. For all rice cultivars, one‐pass IR treatments for 180 s resulted in head rice yield significantly lower than that of rice dried with natural air in the controlled‐environment conditions (P < 0.05). Energy required to dry rice increased with increase in drying duration. Viscosity values of all the experimental samples were significantly greater (P value < 0.05) than that of the control samples for all the cultivars, except those treated with IR for 180 s. There was a significant difference (P < 0.05) in the color index (ΔE ) of treated milled samples and the controls. In conclusion, the study provided information crucial to understanding the effects of scaled‐up radiant heating and tempering of rough rice on drying rates and rice quality for long‐grain pureline, long‐grain hybrid, and medium‐grain rice cultivars.  相似文献   

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Pedohydrological properties were investigated on a piped slope in the Bergisches Land in the Rhenish Slate Mountains (Nordrhein‐Westfalen, Germany). The study confirmed that genesis and development of pipes decisively depend on hydrological conditions in the soils. Vertical water permeability of saturated samples was very high. This promoted fast seepage. Many macropores produced by earthworms also caused high transport capacity for soil water. Even more efficient were the burrows of moles and mice, enabling immediate infiltration and direct vertical and lateral water movement. On the contrary, the horizontal saturated permeability was low indicating no correlation with piping. Porosity of piped soils was not different to that of other soils of the region without pipes.  相似文献   

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Most studies implicitly consider soil carbon dioxide (CO2) efflux as the instantaneous soil respiration and thereby neglect possible changes in the amount of CO2 stored in the soil pore‐space. We measured the CO2 concentration profile of a well‐aerated soil continuously to evaluate the dynamics of the stored CO2 and to analyse the influence of environmental factors. For 25% of the observation period, changes in the amount of stored CO2 accounted for more than 15% of the soil‐CO2 efflux. The following factors were identified to interfere with steady‐state CO2 storage: (i) the fluctuating groundwater table altered the volume of the vadose zone, causing viscous airflow in air‐filled soil pores, (ii) atmospheric turbulence caused pressure‐pumping at the soil–atmosphere interface and (iii) intense rain greatly reduced the diffusivity of the uppermost soil layer. The friction velocity above the canopy was strongly correlated with fluctuations in the differential pressure between soil air and atmosphere, but no static pressure gradient could be detected because of the permeable nature of the soil. Unexpected short‐term declines in the soil CO2 concentration were observed during intense rainfall events. These declines were explained by the intensified CO2 saturation deficit of the infiltrating rainwater caused by the carbonate chemistry of the soil solution.  相似文献   

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In recent time, phytoliths (silicon deposition between plant cells) have been recognized as an important nutrient source for crops. The work presented here aims at highlighting the potential of phytolith‐occluded K pool in ferns. Dicranopteris linearis (D. linearis ) is a common fern in the humid subtropical and tropical regions. Burning of the fern D. linearis is, in slash‐and‐burn regions, a common practice to prepare the soil before planting. We characterised the phytolith‐rich ash derived from the fern D. linearis and phytolith‐associated potassium (K) (phytK), using X‐ray tomographic microscopy in combination with kinetic batch experiments. D. linearis contains up to 3.9 g K/kg d.wt, including K subcompartmented in phytoliths. X‐ray tomographic microscopy visualized an interembedding structure between organic matter and silica, particularly in leaves. Corelease of K and Si observed in the batch experiments confirmed that the dissolution of ash phytoliths is one of major factors controlling K release. Under heat treatment, a part of the K is made available, while the remainder entrapped into phytoliths (ca. 2.0–3.3%) is unavailable until the phytoliths are dissolved. By enhanced removal of organic phases, or forming more stable silica phases, heat treatment changes dissolution properties of the phytoliths, affecting K release for crops and soils. The maximum releases of soluble K and Si were observed for the phytoliths treated at 500–800 °C. For quantitative approaches for the K provision of plants from the soil phytK pool in soils, factors regulating phytolith dissolution rate have to be considered.  相似文献   

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Arabinoxylans are a minor but important constituent in wheat that affects bread quality, foam stability, batter viscosity, and sugar snap cookie diameter. Therefore, it is important to determine the distribution of arabinoxylans in flour mill streams to better formulate flour blends. Thirty‐one genetically pure grain lots representing six wheat classifications common to the western U.S. were milled on a Miag Multomat pilot mill, and 10 flour mill streams were collected from each. A two‐way ANOVA indicated that mill streams were a greater source of variation compared to grain lots for total arabinoxylans (TAX), water‐unextractable arabinoxylans (WUAX), and water‐extractable arabinoxylans (WEAX). TAX and WUAX were highly correlated with ash at r = 0.94 and r = 0.94, respectively; while the correlation for WEAX and ash decreased in magnitude at r = 0.60. However, the 5th middlings mill streams exhibited disparity between TAX and ash content as well as between WUAX and ash content. This may indicate that TAX and WUAX in mill streams are not always the result of bran contamination. Cumulative extraction curves for TAX, WUAX and WEAX revealed increasing gradients of arabinoxylans parallel to extraction rate. Therefore, arabinoxylans may be an indicator of flour refinement.  相似文献   

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The role of anthropogenic activity is increasingly recognized as an agent of environmental change. Photographs, taken more than 130 years ago in KwaZulu‐Natal, South Africa, show a very different landscape to that viewed today. In attempting to understand some of the dynamics behind the changes in the landscape, we explored the history of land‐use in communal rangelands in KwaZulu‐Natal from the arrival of Iron Age man through to modern practices. Communal farming is frequently cited as a major cause of environmental degradation. Traditional lifestyles have been eroded by social, political and economic changes since the arrival of European explorers and settlers in the early 1800s. This may have contributed to encroachment by woody plants into the open savannas and grasslands of KwaZulu‐Natal in recent times because of increased grazing pressure and, perhaps reduced fires. Furthermore, there is decreasing dependence on wood for everyday needs due to the increased availability of electricity. Interviews with a number of community members indicate that they have noted a change in climate and in vegetation structure. Their observations have been confirmed by climate data and historic photographs. Environmental planners need to view change in a holistic manner, taking cognisance not only of the physical changes but also of the history of land‐use and human needs and to give credence to community perceptions. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

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For a case study area in the Okhombe catchment in the province of KwaZulu‐Natal, South Africa, a multi‐scale analysis of soil erosion dynamics was performed. At sub‐catchment level, the dynamics of erosional features were investigated by means of aerial photographs. At site level, the changes in soil physical and chemical properties were investigated by means of a fence‐line contrast study. Attention was paid to both surface and subsurface erosion phenomena. The number of erosional features in the study area in 2000 was not substantially different from the number of features in 1945. At sub‐catchment level, an increase in the number of gullies was observed from 1975 to 2000 but this followed a substantial inactivation of most erosional features from 1962 to 1975. Increases in erosional activity in 1962 compared to 1945 were mainly related to abandoned cultivated fields. At site level, a significant decrease in soil C/N ratio was observed within the fenced site within three years. For the same site, total carbon, saturated hydraulic conductivity and bulk density were not significantly different for the topsoil inside the fenced area compared with outside. Subsurface erosion phenomena mainly occur in the communal grazing areas and are mostly related to transitions between permeable and less permeable layers. The complex relationships between soil erosion, land use change and climate might further be understood by involving local people in the development, monitoring and evaluation of alternative types of land use, which is also likely to facilitate future steps in controlled grazing management. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

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Two hydroponic culture experiments were conducted to investigate cadmium (Cd)‐induced oxidative stress in winter wheat (Triticum aestivum L.) seedlings and the effects of L‐Galactono‐1, 4‐lactone (GalL), the biosynthetic precursor of the antioxidant ascorbate (AsA), on the oxidative stress induced by Cd. In experiment 1, with application of Cd (0, 10, 25, 50 µM) in nutrient solution, hydrogen peroxide (H2O2) and malondialdehyde (MDA) levels as well as membrane permeability in both shoots and roots were significantly increased, indicating Cd‐induced oxidative stress and lipid peroxidation as well as plasma‐membrane damage in the plants. In experiment 2, H2O2 levels in plants exposed to Cd were significantly reduced by the addition of GalL (25 mM), associated with increased activities of peroxidase (POD), indicating that GalL alleviated the oxidative stress induced by Cd. Unexpectedly, however, the MDA levels were not reduced by the addition of GalL. Does Cd also induce lipid peroxidation directly besides via formation of reactive oxygen species (ROS)? This needs further study.  相似文献   

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Wet okara (soy milk residue), as a functional ingredient, was evaluated to be added to a coconut‐based snack at 10, 20, 30, 40, and 50% levels to replace dry coconut in the formula. Certain physicochemical, nutritional, and sensory properties of the samples were evaluated. A coconut‐based, soft, baked snack with incorporated okara showed higher total fiber and much lower fat content than the control, which significantly improved the nutritional profile of the samples. Samples 3 and 4 (which had 30 and 40% replacement of coconut with wet okara, respectively) received the highest overall sensory score (8.4), which was significantly higher than the score of a control sample (7.5). Sample 3 also had a significantly improved nutritional profile per serving size, such as an increased fiber content of 6.11 ± 0.04 g/100 g and a decreased fat content of 17.57 ± 0.02 g/100 g, and sample 4 had an increased fiber content of 6.19 ± 0.03 g/100 g and a decreased fat content of 15.64 ± 0.03 g/100 g compared with the control sample. The appearance, color, flavor, physical measurements (instrumental texture profile analysis), and water activity of samples 3 and 4 were not significantly different from the control sample and demonstrated potential application of this formulation in the baking industry, proving that the wet okara can be successfully used as a value‐added functional ingredient.  相似文献   

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Studies were conducted with two newly developed gluten‐free bread recipes. One was based on corn starch (relative amount 54), brown rice (25), soya (12.5), and buckwheat flour (8.5), while the other contained brown rice flour (50), skim milk powder (37.5), whole egg (30), potato (25), and corn starch (12.5), and soya flour (12.5). The hydrocolloids used were xanthan gum (1.25) and xanthan (0.9) plus konjac gum (1.5), respectively. Wheat bread and gluten‐free bread made from commercial flour mix were included for comparison. Baking tests showed that wheat and the bread made from the commercial flour mix yielded significantly higher loaf volumes (P < 0.01). All the gluten‐free breads were brittle after two days of storage, detectable by the occurrence of fracture, and the decrease in springiness (P < 0.01), cohesiveness (P < 0.01), and resilience (P < 0.01) derived from texture profile analysis. However, these changes were generally less pronounced for the dairy‐based gluten‐free bread, indicating a better keeping quality. Confocal laser‐scanning microscopy showed that the dairy‐based gluten‐free bread crumb contained network‐like structures resembling the gluten network in wheat bread crumb. It was concluded that the formation of a continuous protein phase is critical for an improved keeping quality of gluten‐free bread.  相似文献   

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The pH‐value is of utmost relevance for soil properties and functioning. Hence, a time‐resolved in‐situ measurement is mandatory but lacking. As an alternative, a two‐probe pH electrode with gel‐covered reference electrode was newly constructed and tested for a continuous, in‐situ pH recording in saturated and unsaturated soil. This was done using samples from a set of 14 soils with different composition and pH$ _{\rm CaCl_2} $ ranging from 3.5 to 7.5 in batch and repacked soil column experiments. In the latter, changes in pH and redox potential were monitored upon transport of citrate‐phosphate buffer and pig slurry through the soil columns. The pH measurements were largely stable even upon substantial shifts in soil moisture content down to air‐dry conditions. The results of the pH measurements agreed with standard methods using settled soil suspensions in electrolyte solutions and the conventional combination (single‐probe) pH electrode. Testing the suspension effect, it was found that measuring pH directly in the soil is recommended. The pH measured in‐situ was closest to pH values determined in 0.01 M CaCl2 suspensions according to DIN ISO 10390 (DIN, 2005 ). The transport of citrate buffer and pig slurry as pH active substances through soil induced strong effects on the pH and in part on the redox potential; the reversible effects lasted over days, which may affect the mobility and speciation of nutrients and pollutants as well as microbial processes.  相似文献   

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Simple tools for diagnosing crop nutritional status are in great demand by agricultural extension staff, particularly in low‐fertility environments. We developed the first practical method for in situ diagnosis of phosphorus (P) nutrition in field‐grown cereal crops by using a handheld colorimeter. The concentration of P in extracts from fresh leaves of lowland rice grown under various P availabilities was closely correlated with that of oven‐dried leaves measured with the standard molybdenum‐blue method in the laboratory, over a range of values from 0.319 to 1.420 mg P g ?1 DW (r = 0.885**, n = 14). It takes only 3–5 min to estimate the P concentration of plant samples using the new technique. Although not as accurate as the laboratory method, the new method can easily detect P deficiency of rice in the field (and possibly other cereal crops) without requiring costly, off‐site equipment. Thus, extension staff and agronomists can easily adopt this technique.  相似文献   

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