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1.
Mechanical and chemical treatments to accelerate the drying of cut lucerne were evaluated under laboratory conditions. Plant material was treated with a 016 M solution of potassium carbonate (K2CO3) and/or lightly pressed between a pair of smooth rollers (roll-conditioning).
Drying times to 33% moisture content (MC), expressed on a dry weight basis (dwb), were reduced by 49% by roll-conditioning, 76% by K2CO3) treatment and 77% by the combined K2CO3+ roll-conditioning treatment. The main benefit from combining the two forms of treatment was an improved uniformity of drying; when whole shoots were at 61% MC (dwb) the difference between leaf and stem moisture contents was reduced by 28% (roll-conditioning), 38% (K2CO3) and 54% (K2CO3+ roll-conditioning) relative to the untreated control.  相似文献   

2.
Functional properties of conventional oat materials are relatively poor with respect to foam and emulsion formation and stabilization. This is largely due to the poor solubility of oat proteins and the presence of lipids in aqueous extracts of oats. In the experimental part of this study, extracts were prepared from different type oat flours (oat endosperm flour, oat fine flour, CO2-defatted whole oat flour and CO2-defatted oat flour) with a buffered aqueous extraction procedure at acidic (pH 4.5 and 6.5) and basic (pH 8.5 and 10.5) regions. The solubility of proteins was the highest at pH 10.5 and NaCl concentration of 2%. Among the extracts, CO2-oat flour showed improved foaming and emulsifying properties at basic pH values. The presence of 0.1% NaCl resulted in the lowest foam volumes, but the emulsion activity and stability values being the highest. Sucrose addition resulted in increased foam and emulsion stability of suspensions. Heat treatment at 80 °C impaired foam properties, whereas the stability of emulsions increased with the increase in temperature from 20 °C to 80 °C. CO2-extracted oats can be useful raw materials in beverages and other aqueous applications where protein functionality plays an important role.  相似文献   

3.
We test the hypothesis that reduction in grain N concentration under elevated CO2 concentration (e[CO2]) is associated with N types (NH4+ and NO3−) and their ratios. Wheat (Triticum aestivum L. cv. H45) was grown in a glasshouse under two CO2 concentrations (389 μmol mol−1 and 700 μmol mol−1), supplied with equal amount of N with different ratios of NH4+ and NO3−: (i) 100% NO3−–N; (ii) 50% NO3−–N and 50% NH4+–N; and (iii) 25% NO3−–N and 75% NH4+–N. Plant growth, N uptake and partitioning were measured during plant development. Plant biomass and grain yield was increased at e[CO2] when N was supplied as an equal proportion of NO3− and NH4+. Despite the yield increment, grain N concentration was not affected by e[CO2], in 50% NO3−–N treatment. In contrast, grain N concentration decreased in 100% NO3−–N and 25% NO3−–N treatments. In 50% NO3−–N treatment, N uptake during post-anthesis stage (from 69 to 141 days after planting) was significantly stimulated under e[CO2] compared to 100% NO3−–N and 25% NO3−–N treatments. We concluded that supplement of N in an equal proportion of NO3− and NH4+ which increases post-anthesis N uptake, avoid the reduction of grain N concentration under e[CO2].  相似文献   

4.
Conventional puddled transplanted rice (TPR) is a major source of greenhouse gas (GHG), particularly methane, causing global warming. Direct-seeded rice (DSR) is a feasible alternative to mitigate methane emission, besides saving water and labor. A 2-year field experiment was carried out to quantify GHG mitigation and water- and labor-saving potentials of the DSR crop compared to TPR in three villages in Jalandhar district of Punjab, India. The InfoRCT simulation model was used to calculate the emission of CO2 besides CH4 and N2O in different districts of Punjab, India. Total global warming potential (GWP) in transplanted rice in various districts of Punjab ranged from 2.0 to 4.6 t CO2 eq. ha?1 and in the DSR it ranged from 1.3 to 2.9 t CO2 eq. ha?1. Extrapolation analysis showed that if the entire area under TPR in the state is converted to DSR, the GWP will be reduced by 33 %, and if 50 % area is converted to DSR the GWP will be reduced by 16.6 % of the current emission. The DSR crop saved 3–4 irrigations compared to the transplanted rice without any yield penalty. Human labor use also reduced to 45 % and tractor use to 58 % in the DSR compared to TPR.  相似文献   

5.
Sago pith non-starch polysaccharides were fractionated into cold water solubles (2.6%), hot water solubles (0.8%), dimethylsulfoxide solubles (0.8%), 5% NaOH soluble hemicelluloses (1.2%), 24% KOH–2% H3BO3 soluble hemicelluloses (0.6%), and cellulose (5.3%). Lignin was measured by 5% NaOH extraction (0.6%) and sodium chlorite oxidation (4.2%). Glucose and rhamnose were the major sugars in cold and hot water soluble non-starch polysaccharides. The neutral sugars in dimethylsulfoxide (DMSO) soluble non-starch polysaccharides were found to be enriched in rhamnose, xylose, glucose, and arabinose. Extraction of sago pith with aqueous 5% NaOH produced hemicelluloses, which were enriched in xylose and, to a lesser extent, glucose, arabinose, galactose, and rhamnose-containing polysaccharides, together with 7.4% uronic acids and 3.9% lignin. Further extraction of the delignified pith residue with aqueous 24% KOH and 2% H3BO3 removed the residual hemicellulosic fraction, which was enriched in glucose and xylose-containing polysaccharides, together with 5.8% uronic acids and 1.1% associated residual lignin. Six phenolic acids and aldehydes were detected in the mixtures of alkaline nitrobenzene oxidation of 5% NaOH soluble lignin and associated lignin in hemicelluloses and cellulose fractions. The lignin fraction contained a high proportion of non-condensed syringyl units and small amounts of non-condensed guaiacyl units as well as fewer non-condensed p-hydroxyphenyl units.  相似文献   

6.
Over time, the relative effect of elevated [CO2] on the photosynthesis and dry matter (DM) production of rice crops is likely to be changed with increasing duration of CO2 exposure. However, there is no systemic information on interactive effects of elevated [CO2] and nitrogen (N) supply on seasonal changes in phosphorus (P) nutrient of rice crops. In order to investigate the interactive effects of these two factors on seasonal changes in plant P concentration, uptake, efficiency and allocation, a free-air CO2 enrichment (FACE) experiment was conducted at Wuxi, Jiangsu, China, in 2001–2003. A japonica cultivar with large panicle was grown at ambient or elevated (ca. 200 μmol mol−1 above ambient) [CO2] and supplied with three levels of N: low (LN, 15 g N m2), medium (MN, 25 g N m2) and high N (HN, 35 g N m2 (2002, 2003)). The MN level was similar to that recommended to local farmers. FACE significantly increased shoot P concentration (dry base) over the season, the average responses varied between 7.3% and 16.2%. Shoot P uptake responses to FACE declined gradually with crop development, with average responses of 57%, 51%, 37%, 26% and 11% on average during the growth periods from transplanting to early-tillering (Period I), early-tillering to mid-tillering (Period II), mid-tillering to panicle initiation (Period III), panicle initiation to heading (Period IV) and heading to grain maturity (Period V), respectively. Seasonal changes in shoot P uptake ratio (i.e., the ratio of shoot P uptake during a given growth period to final shoot P acquisition at grain maturity) responses to FACE followed a similar pattern to that of shoot P uptake, with average responses of 19%, 14%, 3%, −5% and −16% in Periods I, II, III, IV and V of the growth period, respectively. As a result, FACE enhanced shoot P uptake by 33% at grain maturity. P allocation patterns among above-ground organs were not altered by FACE before heading, but it was modified after heading, with a shift in P allocation patterns towards vegetative organ. FACE resulted in the significant decrease in P-use efficiency for biomass across the season and P-use efficiency for grain yield and P harvest index at grain maturity. Generally, there were no interactions between [CO2] and N supply on above P nutrient variables measured. Data from this study has important implications for P management in rice production systems under future elevated [CO2] conditions.  相似文献   

7.
Although common disturbances of grazing lands like plant defoliation are expected to affect their sensitivity to increasing atmospheric CO2 concentration, almost no research has been conducted to evaluate how important such effects might be on the direct responses of rangelands to CO2. This growth chamber experiment subjected intact plant–soil cylinders from a Wyoming, USA, prairie to a 3‐way factorial of CO2 (370 vs. 720 μL L?1), defoliation (non‐clipped vs. clipped) and soil nitrogen (control vs. 10 g m?2 added N) under simulated natural climatic conditions. Above‐ and below‐ground biomass and N dynamics of the functional groups C3 grasses, C4 grasses and forbs were investigated. CO2 and defoliation had independent influences on biomass and N parameters of these rangeland plants. Growth under CO2‐enriched conditions enhanced above‐ground biomass 50% in C3 grasses alone, while shoot N concentration declined 16% in both C3 and C4 grasses. Plant‐soil 15N uptake was unaffected by CO2 treatment. In contrast, defoliation had no effect on biomass, but increased tissue N concentration 29% across all functional groups. Without additional N, forage quality, which is in direct relation to N concentration, will decline under increasing atmospheric CO2. Increased dominance of C3 grasses plus reduced forage quality may necessitate changes in grazing management practices in mixed‐species rangelands.  相似文献   

8.
The increase in atmospheric CO2 concentration [CO2] has been demonstrated to stimulate growth of C3 crops. Although barley is one of the important cereals of the world, little information exists about the effect of elevated [CO2] on grain yield of this crop, and realistic data from field experiments are lacking. Therefore, winter barley was grown within a crop rotation over two rotation cycles (2000 and 2003) at present and elevated [CO2](375 ppm and 550 ppm) and at two levels of nitrogen supply (adequate (N2): 262 kg ha−1 in 1st year and 179 kg ha−1 in 2nd year) and 50% of adequate (N1)). The experiments were carried out in a free air CO2 enrichment (FACE) system in Braunschweig, Germany. The reduction in nitrogen supply decreased seasonal radiation absorption of the green canopy under ambient [CO2] by 23%, while CO2 enrichment had a positive effect under low nitrogen (+8%). Radiation use efficiency was increased by CO2 elevation under both N levels (+12%). The CO2 effect on final above ground biomass was similar for both nitrogen treatments (N1: +16%; N2: +13%). CO2 enrichment did not affect leaf biomass, but increased ear and stem biomass. In addition, final stem dry weight was higher under low (+27%) than under high nitrogen (+13%). Similar findings were obtained for the amount of stem reserves available during grain filling. Relative CO2 response of grain yield was independent of nitrogen supply (N1: +13%; N2: +12%). The positive CO2 effect on grain yield was primarily due to a higher grain number, while changes of individual grain weight were small. This corresponds to the findings that under low nitrogen grain growth was unaffected by CO2 and that under adequate nitrogen the positive effect on grain filling rate was counterbalanced by shortening of grain filling duration.  相似文献   

9.
Water management is an important factor in regulating soil respiration and the net ecosystem exchange of CO2 (NEE) between croplands and atmosphere. However, how water management affects soil respiration and the NEE of paddy fields remains unexplored. Thus, a 2-year field experiment was carried out to study the effects of controlled irrigation (CI) during the rice season on the variation of soil respiration and NEE, with flooding irrigation (FI) as the control. A decrease of irrigation water input by 46.39% did not significantly affect rice yield but significantly increased irrigation water use efficiency by 0.99 kg m?3. The soil respiration rate of CI paddy fields was larger than that of FI paddy fields except during the ripening stage. Natural drying management during the ripening stage resulted in a significant increase of the soil respiration rate of the FI paddy fields. Variations of NEE with different water managements were opposite to soil respiration rates during the whole rice growth stages. Total CO2 emission of CI paddy fields through soil respiration (total R soil) increased by 11.66% compared with FI paddy fields. The increase of total R soil resulted in the significant decrease of total net CO2 absorption of CI paddy fields by 11.57% compared with FI paddy fields (p < 0.05). There were inter-annual differences of soil respiration and the NEE of paddy fields. Frequent alternate wetting and drying processes in the CI paddy fields were the main factors influencing soil respiration and NEE. CI management slightly enhanced the rice dry matter amount but accelerated the consumption and decomposition of soil organic carbon and significantly increased soil respiration, which led to the decrease of net CO2 absorption. CI management and organic carbon input technologies should be combined in applications to achieve sustainable use of water and soil resources in paddy fields.  相似文献   

10.
Soil solarisation together with the application of animal manure has been described as an alternative process for control of Phytophthora capsici root rot in pepper crops. A mixture of fresh sheep manure and dry chicken litter (SCM) and a semi-composted mixture of horse manure and chicken litter (HCM) were applied at 5.1 kg m−2 (dry weight) under plastic sheets to reduce Phytophthora inoculum survival rate and disease incidence. Non-solarised (C) and solarised (S) soils were used as control treatments. Mean NH3 concentration increased in SCM during biodisinfestation process (14.8 mg NH3 m−3) compared with HCM (9.1 mg NH3 m−3), accounted for the higher organic N content and potential N mineralisation. The higher NH3 concentration in SCM could have contributed to reduce the inoculum survival rate (30.6% and 75.0% in SCM and HCM plots, respectively). Inoculum survival rate was not reduced in S (94.4%) as temperature was below 33 °C throughout the experimental period. After biodisinfestation treatment, N2O and CO2 emissions tended to be higher in SCM, despite high spatial variability. Cumulative N2O emissions were 1.31 and 0.42 g N2O-N m−2 in SCM and HCM after 43 days. The larger N application and organic N mineralisation rate on fresh manure amended soils might have contributed to higher N2O emissions during and after soil biodisinfestation by denitrification and nitrification, respectively. Cumulative CO2 emission averaged 211.0 and 159.9 g CO2-C m−2 in SCM and HCM, respectively. The soluble organic C, more abundant in fresh manure, might have favoured soil respiration in SCM. Disease incidence decreased in SCM and HCM plots (disease incidence, 2%-8%) in relation to solarised soils (42%) after 4 months. Microbial suppressiveness might have contributed to minimise Phytophthora disease incidence in SCM and HCM plots. Pepper fruit yield increased with manure amendment in SCM and HCM, which averaged 4.6 and 4.3 kg m−2, respectively. Further research will be necessary to guarantee an effective Phytophthora biodisinfestation by fitting manure N and organic matter applications, improving crop yield and reducing greenhouse gas pollution.  相似文献   

11.
王玉娜  米国华 《玉米科学》2021,29(3):151-158
依据文献资料以及农户调研数据,对北方玉米种植区的施肥现状和节肥潜力进行分析。调研数据表明,在当前北方玉米区平均玉米产量为9 894 kg/hm~2水平下,养分投入总量平均为512 kg/hm~2,纯氮(N)投入总量为307 kg/hm~2,纯磷(P_2O_5)投入总量为137 kg/hm~2,纯钾(K_2O)投入总量为68 kg/hm~2。氮、磷、钾肥的偏生产力分别为33、78、135 kg/kg。当前农户施肥量总体超量,以最优化肥偏生产力为依据,推荐当前土壤条件下的北方玉米的平均氮、磷、钾施用量分别为193、86和60 kg/hm~2。各区域均需要不同程度地减少氮磷肥投入,其中,陕西省的氮素节肥潜力最大(53%),黑龙江省的磷肥节肥潜力最大(50%)。吉林、内蒙古、新疆钾肥节肥潜力是26%～41%,黑龙江省、陕西省和甘肃省的钾肥施用量不足,需增施钾肥。  相似文献   

12.
Spring wheat (Triticum aestivum L. cv. Triso) was grown in a free-air CO2 enrichment (FACE) field experiment in order to gain information on CO2-induced effects on grain composition and quality at maturity. A proteome analysis was performed using two-dimensional gel electrophoresis (2-DE) and protein identification was done with mass spectrometry (MALDI-TOF MS). In elevated CO2 (526 μl l−1), an increase of 13.5% in grain yield was observed relative to 375 μl l−1 at a low level of significance (P = 0.528). Total grain protein concentration was decreased by 3.5% at a high level of statistical significance. Most importantly, a number of statistically significant changes within the grain proteome were observed, as the levels of 32 proteins were affected by elevated CO2: 16 proteins were up-regulated and 16 were down-regulated. Our experiment demonstrates that high-CO2 can markedly affect the proteome of mature wheat grain. The potential role of the proteins, changed in response to CO2 enrichment, is discussed as some may affect grain quality. For the task of selecting cultivars resistant to CO2-induced quality loss, we propose to consider the proteins affected by elevated CO2 identified in this work here.  相似文献   

13.
《Field Crops Research》1987,17(1):63-74
Maize crops grown in open fumigation chambers under field conditions were exposed to four levels of atmospheric CO2 supply and two levels of water supply. Photosynthetic and respiratory activities were assessed from elemental analyses of above-ground biomass. Elemental composition varied little with CO2 or water treatment. The mean elemental composition of organic materials per 100 g biomass at a harvest during grain filling was C3.63 H6.04 N0.093 O2.87 S0.002. (The balance of the mass, 2.08 g, was due to minerals). That material had more C and H and less N and was more reduced chemically than pre-anthesis biomass. While crop growth rates were affected by CO2 and water, the growth respiration factor (0.11 g C g−1 biomass and the fraction of estimated gross photosynthesis used in growth respiration were small and unaffected by treatment. It is estimated that net carbon storage amounted to 53% of gross photosynthesis while 14% went to growth respiration and 33% went to maintenance.  相似文献   

14.
Hybrid indica rice (Oryza sativa L.) cultivars play an important role in rice production system due to its heterosis, resistance to environmental stress, large panicle and high yield potential. However, no attention has been given to its yield responses to rising atmospheric [CO2] in conjunction with nitrogen (N) availability. Therefore we conducted a free air CO2 enrichment (FACE) experiment at Yangzhou, Jiangsu, China (119°42′0′′E, 32°35′5′′N), in 2004–2006. A three-line hybrid indica rice cv. Shanyou 63 was grown at ambient and elevated (ca. 570 μmol mol−1) [CO2] under two levels of supplemental N (12.5 g Nm−2 and 25 g Nm−2). Elevated [CO2] had no effect on phenology, but substantially enhanced grain yield (+34%). The magnitude of yield response to [CO2] was independent of N fertilization, but varied among different years. On average, elevated [CO2] increased the panicle number per square meter by 10%, due to an increase in maximum tiller number under enrich [CO2], while productive tiller ratio remained unaffected. Spikelet number per panicle also showed an average increase of 10% due to elevated [CO2], which was supported by increased plant height and stem dry weight per tiller. Meanwhile, elevated [CO2] caused a significant enhancement in both filled spikelet percentage (+5%) and individual grain weight (+4%). Compared with the two prior FACE studies on rice, hybrid indica rice cultivar appears to profit much more from elevated [CO2] than japonica rice cultivar (ca. +13%), not only due to its stronger sink generation, but also enhanced capacity to utilize the carbon sources in a high [CO2] environment. The above data has significant implication with respect to N strategies and cultivar selection under projected future [CO2] levels.  相似文献   

15.
In order to investigate the intra-specific variation of wheat grain quality response to elevated atmospheric CO2 concentration (e[CO2]), eight wheat (Triticum aestivum L.)cultivars were grown at two CO2 concentrations ([CO2]) (current atmospheric, 389 CO2 μmol mol−1vs. e[CO2], FACE (Free-Air CO2 Enrichment), 550  ±  10% CO2 μmol mol−1), at two water levels (rain-fed vs. irrigated) and at two times of sowing (TOS1, vs. TOS2). The TOS treatment was mainly imposed to understand whether e[CO2] could modify the effects of timing of higher grain filling temperatures on grain quality. When plants were grown at TOS1, TKW (thousand kernel weight), grain test weight, hardness index, P, Ca, Na and phytate were not significantly changed under e[CO2]. On the other hand, e[CO2] increased TKW (16%), hardness index (9%), kernel diameter (6%), test weight (2%) but decreased grain protein (10%) and grain phytate (11%) at TOS2. In regard to grain Zn, Mn and Cu concentrations and some flour rheological properties, cultivar specific responses to e[CO2] were observed at both sowing times. Observed genetic variability in response to e[CO2] in terms of grain minerals and flour rheological properties could be easily incorporated into future wheat breeding programs to enable adaptation to climate change.  相似文献   

16.
Mature dark red seeds of cowpea (Vigna unguiculata (L.) Walp.) UPL Cp 3, were subjected to several soaking treatments to remove their polyphenols. Soaking in water at room temperature for 8 and 24 h resulted in 17% and 21% loss of assayable polyphenols, respectively. Dilute solutions of alkali (Na2CO3, NaHCO3, NH4OH and KOH) and acid (CH3 COOH, HCl and H2 SO4) were more effective in removing polyphenols up to 88% than higher concentrations of alkali and acid solutions.Vinegar (0.005–0.65 M CH3 COOH) decreased polyphenols from 55 to 62% with a 6 to 14% improvement in in vitro protein digestibility (IVPD). Commercial lime (65% CaO) removed polyphenols from seeds soaked for 8 to 24 h by 70% with 2 to 10% increase in in vitro protein digestibility. Ash removed 40 to 60% of the polyphenols after 8 and 24 h of soaking with an increase in IVPD of 7 to 13%. Total polyphenols were significantly correlated (+0.92**) with protein precipitable polyphenols (condensed tannins).  相似文献   

17.
Climate change with increasing temperature and ocean acidification (OA) poses risks for marine ecosystems. According to Pörtner and Farrell [1], synergistic effects of elevated temperature and CO2-induced OA on energy metabolism will narrow the thermal tolerance window of marine ectothermal animals. To test this hypothesis, we investigated the effect of an acute temperature rise on energy metabolism of the oyster, Crassostrea gigas chronically exposed to elevated CO2 levels (partial pressure of CO2 in the seawater ~0.15 kPa, seawater pH ~ 7.7). Within one month of incubation at elevated Pco2 and 15 °C hemolymph pH fell (pHe = 7.1 ± 0.2 (CO2-group) vs. 7.6 ± 0.1 (control)) and Peco2 values in hemolymph increased (0.5 ± 0.2 kPa (CO2-group) vs. 0.2 ± 0.04 kPa (control)). Slightly but significantly elevated bicarbonate concentrations in the hemolymph of CO2-incubated oysters ([HCO− 3]e = 1.8 ± 0.3 mM (CO2-group) vs. 1.3 ± 0.1 mM (control)) indicate only minimal regulation of extracellular acid-base status. At the acclimation temperature of 15 °C the OA-induced decrease in pHe did not lead to metabolic depression in oysters as standard metabolism rates (SMR) of CO2-exposed oysters were similar to controls. Upon acute warming SMR rose in both groups, but displayed a stronger increase in the CO2-incubated group. Investigation in isolated gill cells revealed a similar temperaturedependence of respiration between groups. Furthermore, the fraction of cellular energy demand for ion regulation via Na+/K+-ATPase was not affected by chronic hypercapnia or temperature. Metabolic profiling using 1H-NMR spectroscopy revealed substantial changes in some tissues following OA exposure at 15 °C. In mantle tissue alanine and ATP levels decreased significantly whereas an increase in succinate levels was observed in gill tissue. These findings suggest shifts in metabolic pathways following OA-exposure. Our study confirms that OA affects energy metabolism in oysters and suggests that climate change may affect populations of sessile coastal invertebrates such as mollusks.  相似文献   

18.
Various populations of hemicellulosic material were solubilised from water-unextractable cell wall material (WUS) of sorghum (Sorghum vulgarecv. Fara Fara) by sequential extractions with alkali. Saturated Ba(OH)2-solutions, followed by distilled water, 1 KOH, 4 KOH and 4 KOH containing 4% (w/v) H3BO3 were used to extract primarily glucuronoarabinoxylans (GAX) from sorghum WUS. Cellulose remained in the residue. In total over 90% of all GAX originally present in the WUS were recovered, particularly in the saturated Ba(OH)2, 1 KOH and 4 KOH extracts. Saturated Ba(OH)2 was found to be the most selective of the extractants tested for GAX. (1→3), (1→4)-β- -glucans were found predominantly in the fraction obtained by washing with water after the extraction with saturated Ba(OH)2. All extracted arabinoxylans were highly substituted (arabinose/xylose>1) and contained, besides -arabinose and -xylose, the acidic sugars -glucuronic, 4-O-methyl- -glucuronic and -galacturonic acid. The average molecular weight ranged from 210 000–1 300 000, which corresponds with DPs ofc. 1500 to 9300. The selectivity of the extractant was apparently enhanced by the presence of a bivalent cation.  相似文献   

19.
We investigated wheat (Triticum aestivum) grain quality under Free Air CO2 Enrichment (FACE) of 550 ± 10% CO2 μmol mol−1. In each of two full growing seasons (2008 and 2009), two times of sowing were compared, with late sowing designed to mimic high temperature during grain filling. Grain samples were subjected to a range of physical, nutritional and rheological quality assessments. Elevated CO2 increased thousand grain weight (8%) and grain diameter (5%). Flour protein concentration was reduced by 11% at e[CO2], with the highest reduction being observed at the late time of sowing in 2009, (15%). Most of the grain mineral concentrations decreased under e[CO2] - Ca (11%), Mg (7%), P (11%) and S (7%), Fe (10%), Zn (17%), Na (19%), while total uptake of these nutrients per unit ground area increased. Rheological properties of the flour were altered by e[CO2] and bread volume reduced by 7%. Phytate concentration in grains tended to decrease (17%) at e[CO2] while grain fructan concentration remained unchanged. The data suggest that rising atmospheric [CO2] will reduce the nutritional and rheological quality of wheat grain, but at high temperature, e[CO2] effects may be moderated. Reduced phytate concentrations at e[CO2] may improve bioavailability of Fe and Zn in wheat grain.  相似文献   

20.
Because CO2 is needed for plant photosynthesis, the increase in atmospheric CO2 concentration ([CO2]) has the potential to enhance the growth and yield of rice (Oryza sativa L.), but little is known regarding the impact of elevated [CO2] on grain quality of rice, especially under different N availability. In order to investigate the interactive effects of [CO2] and N supply on rice quality, we conducted a free-air CO2 enrichment (FACE) experiment at Wuxi, Jiangsu, China, in 2001–2003. A long-duration rice japonica with large panicle (cv. Wuxiangging 14) was grown at ambient or elevated (ca. 200 μmol mol−1 above ambient) [CO2] under three levels of N: low (LN, 15 g N m2), medium (MN, 25 g N m2) and high N (HN, 35 g N m2 (2002, 2003)). The MN level was similar to that recommended to local farmers. FACE significant increased rough (+12.8%), brown (+13.2%) and milled rice yield (+10.7%), while markedly reducing head rice yield (−13.3%); FACE caused serious deterioration of processing suitability (milled rice percentage −2.0%; head rice percentage −23.5%) and appearance quality (chalky grain percentage +16.9%; chalkiness degree +28.3%) drastically; the nutritive value of grains was also negatively influenced by FACE due to a reduction in protein (−6.0%) and Cu content (−20.0%) in milled rice. By contrast, FACE resulted in better eating/cooking quality (amylose content −3.8%; peak viscosity +4.5%, breakdown +2.9%, setback −27.5%). These changes in grain quality revealed that hardness of grain decreased with elevated [CO2] while cohesiveness and resilience increased when cooked. Overall, N supply had significant influence on rice yield with maximum value occurring at MN, whereas grain quality was less responsive to the N supply, showing trends of better appearance and eating/cooking quality for LN or MN-crops as compared with HN-crops. For most cases, no [CO2] × N interaction was detected for yield and quality parameters. These data suggested that the current recommended rates of N fertilization for rice production should not be modified under projected future [CO2] levels, at least for the similar conditions of this experiment.  相似文献   

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