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1.
Seasonally high nighttime temperatures (HNTs) along the United States Gulf Coast and in regions of similar climate, occurring during the critical stages of development, reduce rice (Oryza sativa L.) yield and quality. The objective of this study was to determine the effects of HNT and preventive exogenous effectors (α-tocopherol, glycine betaine and salicylic acid) on growth, development, physiology and yield of rice plants. Plants were subjected to ambient nighttime temperature (ANT) (27 °C) or HNT (32 °C) through use of continuously controlled infrared heaters, starting from 2000 h until 0600 h. The HNT did not affect leaf photosynthetic rates; however, profound effects on chlorophyll content, leaf nitrogen content, percent pollen germination and spikelet fertility were observed. In addition, HNT hastened plant development rates, as indicated by the panicle emergence date. Plants grown under HNT showed a 90% decrease in yield compared to plants grown under ANT. Dry matter partitioning to the grains of cv. Cocodrie decreased under HNT mainly due to effects on pollen germination and spikelet fertility, but not photosynthesis. Our findings indicate that exogenous application of salicylic acid reduced the negative effects of HNT by 16%. 相似文献
2.
The effects of air temperature and light on the grain filling of an indica (IR20) and ajaponica rice (Fujisaka 5) was studied in artificially lighted cabinets. Within the daily mean temperature range of 16° to 28°C, the higher the temperature, the faster the grains filled and matured. At 28°C, the upper grains of IR20 rice took 13 days to reach the maximum weight, whereas those of Fujisaka 5 took 18 days. The optimum daily mean temperature range to achieve maximum weight per grain was 19° to 25°C for IR20 and 16° to 22°C for Fujisaka 5. Apparently, IR20 rice is better adapted to higher temperatures during the ripening period than is Fujisaka 5 rice. More chalky grains occurred when the temperature was above or below the optimum range. Both day and night temperatures affected grain weight and grain quality. The daily mean temperature was found to be the most meaningful expression for describing the effect of temperature on grain filling. Low light intensity appeared to cause a slight delay in the grain filling of the whole panicle and a reduction in the percentage of filled grains on the lower branches. A combination of high light intensity and low temperature gave the best ripening grade (grain weight × percent filled grains). 相似文献
3.
The effects of heat stress (mean day/night temperatures were 29/18 and 35/18°C for control and heat stress treatments, respectively) at 1–10 or 11–20 days after pollination (DAP) on grain yield and quality of two waxy maize varieties, Suyunuo5 and Yunuo7, were studied. The decrease in grain number and fresh grain yield was more severe when heat stress was introduced early. The responses of grain weight and its components to heat stress were dependent on the variety and heat stress stage. Heat stress increased the starch granule size and volume percentage of diameter larger than 17 μm in both varieties. Crystallinity, iodine binding capacity, and pasting and gelatinization temperatures were increased in both varieties under heat stress at 11–20 DAP; however, the response to early‐stage heat stress was variety dependent. Peak viscosity and retrogradation percentage were increased by heat stress at either stage. These results suggest that heat stress decreases fresh grain yield and accelerates grain filling rate; it increases starch content, starch granule size, crystallinity, and iodine binding capacity as well as decreases the protein content in Yunuo7, thus making the grain less tender and prone to retrogradation. Warm conditions should shorten the time to harvest in fresh waxy maize production. 相似文献
4.
Effects of heat stress (mean day/night temperatures of 35.2/16.1 and 27.4/15.6°C for heat stress and control, respectively) during different grain‐filling phases (1–10, 11–20, 21–30, 31–40, and 1–40 days after pollination [DAP]) on the grain yield and quality of waxy maize were investigated using two varieties. Heat stress decreased the number and weight of grains, thereby reducing grain yield. The effects of heat stress at an early grain development stage (before 20 DAP) were severe. Compared with the control, starch deposition was not affected by heat stress in Suyunuo5, and it was only decreased by heat stress at 1–10 DAP in Yunuo7. Protein content responses to heat stress were variety and stage dependent. Heat stress increased the iodine‐binding capacities of both varieties. Peak and breakdown viscosities were decreased by heat stress, and the effects gradually decreased with postponement of high temperature. Heat stress increased gelatinization temperature and retrogradation percentage for both varieties, and the response was stage dependent. Heat stress during the whole grain‐filling period increased the pasting and gelatinization temperatures but decreased gelatinization enthalpy. Changes in protein and starch contents as well as the proportion of long chains in amylopectin affected the pasting and thermal properties. 相似文献
5.
P. A. Counce R. J. Bryant C. J. Bergman R. C. Bautista Y.‐J. Wang T. J. Siebenmorgen K. A. K. Moldenhauer J.‐F. C. Meullenet 《Cereal Chemistry》2005,82(6):645-648
Important rice grain quality characteristics such as percentage of chalky rice kernels are affected by both high and low night temperatures and by different day and day/night temperature combinations. High nighttime temperatures have also been suspected of reducing rice milling quality including head rice yields. Experiments to confirm or refute this have not been reported. A controlled climate experiment was conducted. Conditions in the chambers were identical except between 2400 and 0500 hours (midnight and 5 am). For those times, two temperature treatments were imposed: 1) 18°C (low temperature treatment) and 2) 24°C (high temperature treatment). Two cultivars were tested: LaGrue and Cypress. The high temperature treatment reduced head rice yields compared with the low temperature treatment. Grain widths were reduced for the high temperature treatment compared with the low temperature treatment. There was no effect of temperature on grain length or thickness. Amylopectin chain lengths 13–24 were increased by the high temperature treatment by ≈1%. Future research will focus on determining whether genetic variability exists among cultivars in their head rice yield response to high temperatures. After identifying a source of resistance to high temperature effects, this characteristic can be incorporated into rice cultivars. In addition, ways to reduce this effect, including biotechnological remedies, have the potential for increasing rice yield and quality. 相似文献
6.
The production of medium‐ and short‐grain rice in the mid‐Southern U.S. rice‐growing region is increasing. This work aimed to identify the quality traits of importance to the markets for these grain types. Twenty‐five medium‐ and short‐grain milled rice samples were collected and analyzed for physical, gelatinization, pasting, and starch structural properties. Six samples were from Arkansas (AR), five from California (CA), and 14 imported (IM). Cluster and principal component analyses showed that the AR samples had greater gelatinization temperature, enthalpy, and percentages of amylopectin long chains (B2 and B3 chains) but lesser kernel whiteness, total setback viscosity, and percentage of amylopectin short chains (A chains) than the CA samples. With the exception of one sample from Taiwan, chemometrics indicated that the IM samples differed from the AR samples (cluster A) in some properties and were grouped into three clusters (clusters B, C, and D). Cluster B samples had properties that were similar to the CA samples; cluster C samples had lower gelatinization temperature and peak viscosity but greater percentages of amylose and A chains than the AR samples; and cluster D samples had lesser paste breakdown but greater final viscosity and percentage of B1 chains than the AR samples. Kernel width, color, and chalk were the primary sources of variation in milled rice appearance. In relation to structure and functionality, the percentages of amylopectin A and B3 chains and amylose content were the major sources of variation. 相似文献
7.
《Soil Science and Plant Nutrition》2013,59(3):412-417
Abstract The effects of different night temperatures on grain yield were examined in rice (Oryza sativa L. Akita-63) during the ripening period. Plants were grown under two different night temperatures (22 and 27°C) from anthesis to harvesting. The day temperature was maintained at 27°C in both treatments. Although the final biomass at harvest did not differ between the treatments, the dry weight of the panicles was significantly greater in the cool night temperature treatment. This increase in panicle weight was associated with increases in the 1000-kernel weight and the ratio of filled spikelets. Although panicle respiration in the high night temperature treatment decreased to almost zero just after the cessation of grain filling, the net CO2 fixation rate per day in the whole plant in this treatment tended to be higher, and this was associated with a higher level of starch accumulation. After grain filling, the starch content decreased and the final dry weight of other plant parts, including dead organs and new tillers, was greater in the high night temperature treatment. Thus, the noted decline in yield at the high night temperature led to changes in carbon allocation to new sinks for vegetative reproduction at the whole plant level. From these results, we considered the possibility that a cool night temperature tends to favor carbon allocation to panicles, resulting in higher yield. 相似文献
8.
Rolfe J. Bryant Ranjit S. Kadan Elaine T. Champagne Bryan T. Vinyard Debbie Boykin 《Cereal Chemistry》2001,78(2):131-137
Waxy (short grain), long grain, and parboiled (long grain) rice flours were extruded using three different temperatures and five different water feed rates. The water absorption and water solubility index of the extrudates was 0.67–5.86 and 86.45–10.03%, respectively. The fat absorption index was similar to that of unextruded flours with an average value of 0.96 g/g ± 0.12. Bulk density decreased with an increase in moisture, except waxy rice, which had a quadratic relationship. The viscosity profiles for long grain and parboiled rice were similar. Both initially increased in viscosity (>130 RVU), then decreased to ≈40 RVU. The final viscosity was ≈60 RVU. Waxy rice viscosity remained low (<20 RVU), then doubled upon cooling. The main difference in the digestion profiles was due to temperature. The flours extruded at 100°C digested significantly slower than those extruded at 125 and 150°C. Significant differences were not detected for a given temperature and moisture (P > 0.05) except for long grain and parboiled rice extruded at 100°C and 15% added moisture (F = 4.48, P = 0.03) and 150°C and 20% added moisture (F = 3.72, P = 0.05). Moisture appeared to have little effect for a given temperature, except when parboiled rice was extruded at 150°C. The digestion rate for 11 and 25% added moisture was significantly less than that for 20% (P ≤ 0.05). 相似文献
9.
To reduce fuel and labor costs and increase profits, farmers are trying new ways of growing rice (Oryza sativa L.). This includes changing crop rotations, tillage systems, and fertilization levels. There is little information on how these changes affect the cooking quality of rice. We therefore looked at the parameters associated with cooking and processing quality (apparent amylose, gelatinization temperature, lipid and protein contents, and pasting properties) of two U.S. long grains (Cybonnet and Wells) that were grown using two different tillage systems, standard rate and high rates of fertilization, and different crop rotations (continuous rice R‐R, rice after soybeans R‐SB, and rice after corn R‐C). No differences in quality traits were observed among any of the tillage systems. Rice grown in continuous rice rotation had the lowest protein content of brown and milled rice (8.6 and 8.1%, respectively) as compared to the highest levels observed in the rice‐soybean rotation (9.3 and 8.6%, respectively). Rice grown in continuous rice rotation also had higher peak viscosity than other crop rotations. Increasing the fertilization rate increased the protein content of brown rice and decreased peak, trough, and final viscosities. Apparent amylose content, gelatinization temperature, and lipid content were not affected by crop rotation or fertility; however, they were influenced by cultivar. Although the results indicated statistical differences for some quality parameters, the differences were small enough that they are unlikely to have a major impact on processing quality of long grain rice if co‐mingled. 相似文献
10.
《Cereal Chemistry》2017,94(4):683-692
In‐bin, on‐farm drying systems for rough rice present challenges for maintaining kernel quality when drying fronts stall and the top layer of grain maintains its harvest moisture content (MC) for extended periods. This high MC, in addition to ambient temperatures in early autumn in the Mid‐South United States, creates ideal conditions for quality losses to occur. This study evaluated the effects of rough rice storage at MCs of 12.5, 16, 19, and 21% for up to 16 weeks at temperatures of 20, 27, and 40°C on milling yields, kernel color, and functionality of three long‐grain cultivars. Head rice yield was negatively impacted only after other reductions in quality had occurred. Temperature‐specific discoloration patterns were observed at 27 and 40°C in 2014; the uniquely discolored kernels seen in 2014 at 27°C were absent from samples in 2015 under identical conditions. Peak viscosity, breakdown, and final viscosity tended to increase over storage duration at 20 and 27°C and all storage MCs but plateaued after 8 weeks. Storage of rice at 40°C and all MCs greatly reduced peak viscosity after 6 weeks. To prevent quality losses, in‐bin dryers should be monitored closely to avoid exceeding the thresholds of storage MC, temperature, and duration identified here. 相似文献
11.
《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
12.
High temperature during grain filling has been identified as a major factor in the end-use properties of bread wheat (Triticum aestivum L.). Our objectives were to assess the effect of high temperature during maturation on the grain characteristics, milling quality, and flour quality of hard red winter wheat. In three separate experiments, plants of wheat cultivar Karl 92 were subjected to regimes (day-night) of 20–20, 25–20, 30–20, and 35–20°C from 10 and 15 days after anthesis (DAA) until ripeness, and 25–20, 30–20, and 35–20°C from 20 DAA until ripeness. In other experiments, plants of wheat cultivars Karl 92 and TAM 107 were dried at 20 and 40°C, and spikes of Karl 92 were dried at different temperature and humidity conditions to asses the effects on quality of high temperature and drying rates during grain ripening. Flour yield correlated positively with kernel weight and diameter, test weight, and proportion of large kernels. Flour yield decreased as temperature increased and correlated negatively with hardness index and proportion of small grains. High growth temperatures and rapid grain desiccation decreased mixing time and tolerance of the flours. The greatest damage occurred when high temperature was maintained continuously from early grain filling until ripeness. Weakening of dough properties by rapid desiccation during ripening suggest that temperature, humidity, and possibly soil moisture all contribute to the final quality of bread wheat. 相似文献
13.
The effects of temperature during grain filling on the quality of fresh waxy maize grain were investigated using three varieties. Plants of the selected varieties were subjected to two temperature treatments, namely, control (mean daily air temperature, 30°C) and heat stress (35°C), after artificial pollination (1–23 days after pollination). Heat stress decreased starch content and crystallinity and increased the contents of protein and protein fractions (albumin, globulin, zein, and glutenin), but it did not affect soluble sugar content in general. The effects of heat stress on grain textural characteristics were variety dependent, except for springiness, which was similar between treatments. Pasting and thermal properties were also affected by heat stress. The results suggest that heat stress during grain filling changes the composition of flour and crystalline structure of starch, thereby decreasing viscosities and enthalpies of gelatinization as well as increasing the pasting and gelatinization temperature of fresh waxy maize. 相似文献
14.
James A. Patindol Terry J. Siebenmorgen Ya‐Jane Wang Sarah B. Lanning Paul A. Counce 《Cereal Chemistry》2014,91(4):350-357
The structural features of starch were examined to better understand the causes of variability in rice quality resulting from nighttime air temperature (NTAT) incidence during kernel development. Starch samples were isolated from head rice of four cultivars (Bengal, Cypress, LaGrue, and XL723) field‐grown in four Arkansas locations (Keiser, Pine Tree, Rohwer, and Stuttgart) in 2009 and 2010. Average NTATs recorded during the grain‐filling stages of rice reproductive growth in the four locations were 3.0–8.4°C greater in 2010 than 2009. Elevated NTATs altered the deposition of starch in the rice endosperm. Means pooled across cultivars and locations showed that amylose content was 3.1% (percentage points) less for the 2010 sample set. The elevated NTATs in 2010 resulted in a decrease in the percentage of amylopectin short chains (DP ≤ 18) and a corresponding increase in the percentage of long chains (DP ≥ 19) by an average of 1.3% (percentage points). The greater NTATs in 2010 also produced greater starch paste peak, final, and breakdown viscosities, whereas setback and total setback viscosities decreased. Changes in paste viscosity were highly correlated with the changes in the proportion of amylose and amylopectin. Onset gelatinization temperature was greater by 3.5°C, gelatinization enthalpy by 1.3 J/g, and relative crystallinity by 1.5% (percentage points) for the 2010 sample set. Changes in gelatinization parameters and granule relative crystallinity were highly correlated with the changes in amylopectin chain‐length distribution. Year × cultivar × location interaction effects were statistically insignificant, indicating that the four cultivars evaluated all showed some degree of susceptibility to the effects of temperature incidence during kernel development, regardless of the growing location. 相似文献
15.
16.
Ashley Han Emily O. Arijaje Jia‐Rong Jinn Andy Mauromoustakos Ya‐Jane Wang 《Cereal Chemistry》2016,93(1):39-46
Germinated brown rice is popular in Asia for its increased γ‐aminobutyric acid (GABA) content and sweeter and softer texture compared with conventional brown rice. However, most studies investigated germinated rice properties on medium‐grain or aromatic rice. The objective of this study was to compare differences between a medium‐grain (Jupiter) and a long‐grain (Wells) rice under similar germination conditions on their milling, physicochemical, and textural properties over the course of germination. Rough rice was soaked in water at 25°C for 12 h and then incubated at 30–34°C for four germination durations. Wells had a higher breakage percentage and a greater weight decrease than Jupiter during germination. Wells had a significantly lower GABA content before germination and at the first two germination durations than Jupiter, but the GABA content in Wells significantly increased at the third germination duration to become significantly higher than that of Jupiter. There were no significant changes in gelatinization temperatures and pasting properties of germinated rice from both cultivars at different germination durations. The cooked rice hardness from Wells decreased at the longest germination duration, whereas Jupiter showed a more significant decrease in cooked rice stickiness from germination. The results demonstrate that the impacts of germination on physical, chemical, and textural properties of rice were affected by grain type and germination duration. 相似文献
17.
《Soil Science and Plant Nutrition》2013,59(1):124-131
Abstract The effects of night temperature on biomass accumulation and plant morphology were examined in rice (Oryza sativa L.) during vegetative growth. Plants were grown under three different night temperatures (17, 22 and 27°C) for 63 days. The day temperature was maintained at 27°C in all treatments. The final biomass of the plants was greatest in the plants grown at the highest night temperature. Total leaf area and tiller number were also the greatest in this treatment. Growth analysis indicated that the relative growth rate in the 27°C night-temperature treatment was maximal between days 21–42 and this was caused by increases in leaf area ratio, leaf weight ratio and specific leaf area. Plant total nitrogen contents did not differ among treatments. However, nitrogen allocation to the leaf blades was highest and the accumulation of sucrose and starch in the leaf blades and sheaths was the lowest in the 27°C night-temperature treatment by day 42. Despite this, dark respiration was also highest, and both the gross and net rates of CO2 uptake at the level of the whole plant at day 63 were the highest in the 27°C night-temperature treatment. Thus, high night temperature strongly stimulated the growth of leaf blades during the early stage of rice plant growth, leading to increased biomass during the vegetative stage of the rice plants. As the CO2 uptake rate per total leaf area was higher, photosynthesis at the level of the whole plant was also stimulated by a high night temperature. 相似文献
18.
With the increasing scarcity of rural labor, the rice transplanting pattern is encountering a shift from artificial transplanting (AT) to mechanical transplanting (MT) in numerous rice‐growing districts of China. The shift of transplanting patterns combined with altered growing environment during the grain‐filling stage in different years presumably affects rice quality. Nevertheless, related information is currently limited. This study investigated the effects of cultivars, transplanting patterns, environment, and their interactions on appearance, milling, eating, and nutritional qualities of four japonica rice varieties. The significant interactive effects of cultivars, environment, and transplanting patterns on almost all rice quality parameters (except Thr, Met, and Ile) were observed. Cultivars and environment were the main factors influencing rice appearance and milling and eating qualities. Cultivar was the primary factor affecting rice nutritional quality. Among all treatments, environment showed the strongest effect on percentage of chalky kernel, milled rice yield, peak viscosity, breakdown, setback, consistence, amylose, Glu, Tyr, and Met contents. However, Leu and Phe contents were unaffected by environment but only by cultivars and transplanting patterns. In addition to amylose and protein, Glu and Met contents were also involved in determining rice eating quality. Amino acid contents (except Cys, Tyr, and Met) were significantly negatively correlated with head rice yield, showing the function of amino acids in controlling rice milling quality. Percentage of chalky kernel as well as protein and almost all amino acid contents were significantly negatively correlated with the difference of maximum and minimum temperature (DMMT) and positively correlated with relative humidity (RH), whereas head rice yield did it reversely. Amylose content and setback were significantly negatively related to daily maximum temperature (DMAT), daily minimum temperature (DMIT), daily average temperature (DAT), and effective temperature accumulation (ETA). However, peak viscosity, breakdown, and consistence had contrary performances. According to these results, we can infer that DMMT and RH are important environmental factors affecting rice appearance, milling qualities, and nutritional qualities and that DMAT, DMIT, DAT, and ETA are key environmental factors influencing rice eating quality. 相似文献
19.
Microwave treatment is a sufficiently alternative technique to be applied widely in food production and cereals protection against insect pests. Water‐soluble proteins were washed out from microwave‐heated wheat grain for the purpose of assaying the influence on biological activities, reducing sugars content, and SDS‐PAGE electrophoresis proteins patterns. The differences between microwave‐heated grain samples were verified by analysis of variance at the P ≤ 0.05 level of significance. Microwave heating of wheat grain within the temperature range of 28–98°C caused a decrease in water‐extractable proteins, statistically significant when grain temperature reached 79 and 98°C. Statistically significant increase in reducing sugars content was noted in grain samples heated only to 48°C; a decrease was noted above this temperature. All biological activities studied (amylolytic and inhibition activities against α‐amylases from insects (Sithophilus granarius L., Tribolium confusum Duv., Ephestia kuehniella Zell.), human saliva, hog pancreas, antitryptic activity) were distinctly diminished in grain samples heated to 79°C. At the highest grain temperature of 98°C, the loss of all biological activities were even more pronounced due to denaturation of ≈45% of extractable proteins. Among the wheat albumins studied by SDS‐PAGE, only eight and nine protein bands were detected in the grains heated to 98 and 28°C, respectively, whereas 12 bands were present in the control. The highest number of protein bands (13) was found in the grains heated to 48 and 64°C, respectively. 相似文献
20.
The proportion of straw and grain as well as of nitrogen (N) in the barley (Hordeum vulgare L.) plant was greatly changed by the distribution of rain in the pre‐ and post‐anthesis periods and by the existence of air temperatures above 30°C during grain filling along with N fertilizer rate. The response of barley to N rates of 0, 40, 80, 120, and 160 kg N/ha was studied over a three‐year period. Adequate rainfall in the pre‐anthesis period, little rain in the post‐anthesis period, and air temperatures above 30°C during the hard dough stage of the grain development, produced high N translocation to the grain as well as a positive response on grain yield and N content in the grain up to a fertilizer rate of 118 N kg/ha. Above this rate, grain yield decreased, while the N content in grain continued to increase. Optimum moisture conditions during the pre‐ and post‐anthesis periods, and mild temperatures during the grain filling period, produced a good grain yield response to N fertilizer rate, increases up to 131 kg N/ha without varying the N content in grain. The N translocation efficiency was somewhat lower than low rainfall in the post‐anthesis period. Low rainfall in the pre‐anthesis period and air temperatures above 30°C in the early milk stage of the grain made grain filling difficult, even when the rainfall was sufficient in the post‐anthesis period. Hence under these conditions, N fertilizer rate did not increase the grain yield, but the N content and the N‐translocation efficiency decreased with increasing N fertilizer rates. 相似文献