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1.
硒对大蒜生理特性、含硒量及品质的影响   总被引:7,自引:2,他引:7  
以金蒜3号为试材,采用盆栽试验,通过叶面喷施不同浓度、不同次数的亚硒酸钠研究了硒对大蒜生理特性、含硒量和品质的影响。结果表明:在生长期4月5日、15日和25日累计喷施1次、2次、3次3个浓度(5、10、15 mg/L)的亚硒酸钠溶液,均不同程度影响大蒜生理特性、含硒量和品质。与对照相比,叶面喷施2次10 mg/L的亚硒酸钠溶液,可显著提高叶片中光合色素含量和光合性能;能显著改善蒜薹和鳞茎品质,单薹鲜质量和单头鲜质量分别提高68.25%和29.00%,可溶性糖、可溶性蛋白、维生素C含量分别提高73.05%、104.66%、18.95%和82.01%、51.27%、69.82%;并可有效提高鳞茎中游离氨基酸含量(38.91%),降低蒜薹中游离氨基酸含量(36.95%);同时可降低蒜薹和鳞茎中大蒜素含量,但差异不显著。蒜薹和鳞茎硒含量随硒浓度和喷施次数的增加而显著提高,最高可达19.81和23.96 mg/kg,为对照的3.85和4.41倍。综合各因素指标,大蒜以叶面喷施2次10 mg/L的亚硒酸钠为宜。  相似文献   

2.
  【目的】  研究固体废矿富硒煤矸石制备硒肥的资源化利用技术。  【方法】  以世界硒都恩施的煤矸石废矿为原料,分别进行了活化剂 (弱碱性物质Na2CO3)、活化时间、活化温度和料液比的单因素6水平试验,测定硒活化率,每个因素筛选出3个水平,采用响应面优化方法进行计算,最终确定富硒煤矸石中硒的活化工艺参数。采用IR光谱、TG热重法对煤矸石活化前后官能团键合、热效应进行表征分析。用活化煤矸石硒肥与养殖场粪肥以1∶1、2∶1、3∶1、和4∶1的比例分别混合后发酵一个月,制备4种活化煤矸石硒有机肥 (简称硒有机肥),以煤矸石硒肥和发酵粪肥作两个对照,以大蒜为试材进行了田间试验。收获后测定了土壤和大蒜鳞茎中的总硒、有机硒含量。  【结果】  单因素试验确定的4个因素用于响应面优化的范围,活化剂Na2CO3的浓度为10%、20%和30%;活化时间为2.5、3.5、4.5 h;活化温度为75℃、85℃和95℃;料液比 (g/mL) 为1∶5、1∶10、1∶15。经过响应面优化计算,当原料粒径为0.038 mm时,最优工艺条件为活化剂的浓度22%、活化时间3.9 h、料液比1:9 g/mL、活化温度85℃。应用此参数活化的煤矸石固体硒肥pH约为7.6、最大活化效率为81.24%。IR光谱曲线显示,Na2CO3的加入破坏了煤矸石中硒与其它的金属、非金属等元素间的弱作用力及网络原子原有的结晶态,使得硒基团解脱束缚,成为活性硒。由TG (thermal gravimetric) 及DTG (derivative thermogravimetry) 曲线可知,煤矸石活化前后的热稳定性有较大变化。活化前样品的DTG曲线出现两个峰,而活化后只在100℃前出现一个峰,且失重情况较活化前弱。因此,活化后的煤矸石硒肥热稳定性更好。活化后煤矸石的硒含量为170.82 mg/kg,制备的4个比例煤矸石硒有机肥的硒含量依次为85.41、113.88、128.05、136.66 mg/kg。在等硒量试验下,5个处理大蒜鳞茎中硒的含量依次为1.033、1.306、1.480、1.382、1.355 μg/g,均显著高于未施硒肥对照组的0.005 μg/g (P < 0.05)。硒肥处理大蒜鳞茎中有机硒比例均在99%以上,高于未施硒肥对照组的60%。硒有机肥处理大蒜吸收硒的效果优于煤矸石硒肥,并以煤矸石固体硒肥与家禽粪2∶1比例混合配置的煤矸石硒有机肥的吸收硒效果最优。  【结论】  Na2CO3活化富硒煤矸石的最佳工艺条件为活化剂的体积质量分数22%、活化时间3.9 h、料液比1∶9 g/mL、活化温度85℃。在该条件下,煤矸石中硒的活化率可高达81.24%,且煤矸石硒肥的热稳定性更好。将煤矸石硒肥与畜禽粪混合发酵,可以大大提高大蒜对硒的吸收量,其中有机硒的比例非常高,故有机肥与活化煤矸石硒肥以1∶2比例混合发酵制备煤矸石硒有机肥是活化煤矸石硒的有效方法。  相似文献   

3.
The relationship between selenium (Se) and sulfur (S) uptake and their interaction on the pungency and quercetin contents of onion was investigated in a sand culture trial under polyhouse conditions. The results indicated that application of Se with increasing rates produced an antagonistic effect on S assimilation. An amount of 20 kg Se ha–1 drastically reduced the S content in onion bulbs. Further, the pungency and quercetin concentration also declined. Foliar application of Se at 1.0 ppm resulted in production of bulbs with lower levels of pungency and quercetin. Though Se is essential from a health point, its application up to 10 kg ha–1 was sufficient for enriching onions without much effect on the other essential bulb quality parameters.  相似文献   

4.
Abstract

In this study, the effect of different levels of nitrogen (N) and potassium (K) fertilizers on vegetative fresh bulb yield, quality and biochemical attributes of sweet fennel were investigated in spring 2017 and 2018. Treatments consisted of 0, 50, 100, or 150?kg ha?1 of N and K in a randomized complete block design with three replications. Results showed that, the bulb fresh yield increased with application of N and K in both years, while the higher level of K had significant adverse effect in first year. Results also showed that sweet fennel bulb treated by N and K exhibited higher vitamin C, total phenols and flavonoid contents, and antioxidant capacity, especially in first year. In both years, alone or combined application of N and K increased total soluble solids (TSS) content as compared to control, and this effect was more pronounced in 2017 season. Macronutrient contents of bulb including magnesium (Mg), phosphorus (P), K, N, and calcium (Ca) were significantly enhanced by NK fertilizer, however an alone application of K decreased Ca and Mg nutrient contents. Therefore, to improve fresh bulb yield, quality and antioxidant capacity in sweet fennel, 150?kg ha?1 K and 100?kg ha?1 N is recommended.  相似文献   

5.
The effects of sodium selenite (SS) and selenium yeast (SY) alone and in combination (MS) on the selenium (Se) content, antioxidant enzyme activities (AEA), total antioxidant capacity (TAC), and oxidative stability of chicken breast meat were investigated. The results showed that the highest (p < 0.05) glutathione peroxidase (GSH-Px) activity was found in the SS-supplemented chicken breast meat; however, SY and MS treatments significantly increased (p < 0.05) the Se content and the activities of catalase (CAT), total superoxide dismutase (T-SOD), and TAC, but decreased (p < 0.05) the malondialdehyde (MDA) content at 42 days of age. Twelve days of storage at 4 °C decreased (p < 0.05) the activity of the GSH-Px, but CAT, T-SOD, and TAC remained stable. SY decreased the lipid oxidation more effectively in chicken breast meat. It was concluded that SY and MS are more effective than SS in increasing the AEA, TAC, and oxidative stability of chicken breast meat.  相似文献   

6.
The availability of inorganic and organic forms of selenium (Se) to garlic was studied by supplying selenium twice during the life cycle under field conditions. Most of the organic seleno compounds were more effectively taken up by garlic than sodium selenite. When sprayed with 50 mL 100 ppm O,O-diethyl-(N-selenomorpholinyl)phosphonate, the selenium content of the garlic bulb increased from 0.138 ppm to 1.734 ppm. When sprayed with 3-butyl selenomorpholine hydrochloride and 4-amino benzenesulfonyl selenomorpholine hydrochloride, the selenium content of the garlic leaf increased from 0.240 ppm to 7.32 ppm and 6.03ppm, respectively.  相似文献   

7.
Onion is the one of the most important vegetable crops grown extensively throughout the world; hence, understanding the response of the crop to the form and amount of N provided is of immense importance. In a field experiment, poultry and cattle manure (at 10?t/ha) were compared with four inorganic nitrogen (N) application levels (0, 60, 90 and 120?kg?N/ha), and six combinations of manure and N applications were investigated. Plant growth and total yield (kg/ha) significantly increased, when N application increased from 0 to 120?kg/ha, with or without added poultry manure. Plant height, leaf number and neck thickness were significantly reduced at 0?kg/ha?N plus cattle manure. The bulb ascorbic acid concentration significantly increased with the use of poultry manure (15.94?mg/100?g) and cattle manure (15.94?mg/100?g), compared with 120?kg/ha inorganic N (11.42?mg/100?g). No significant effects were observed on total phenolics and total soluble solids of onion bulbs following the different fertiliser treatments. Cattle manure increased P and K concentrations, whilst poultry manure significantly increased Zn and Fe concentrations in onion bulbs. Onion bulb Ca and Mg concentrations were lower when cattle manure (0.19% and 0.12%) was used than when other organic or inorganic fertilisers were used. Therefore, organic manure increases the concentrations of certain minerals in onions, compared with inorganic N application, without negatively affecting bulb size.  相似文献   

8.
天然富硒土壤上三种蔬菜对硒的吸收与转化差异   总被引:1,自引:1,他引:0  
【目的】研究对硒 (Se) 不同敏感性蔬菜对天然富硒土 (Se ≥ 0.4 mg/kg) 中硒的吸收和转化差异,为富硒土壤生产富硒蔬菜提供理论与技术指导。【方法】以大蒜、芥菜和菠菜三种蔬菜为试验材料,在全硒含量为0.29、0.58、0.98、2.07 mg/kg的四种土壤上进行了盆栽试验 (依次标记为Se0.29、Se0.58、Se0.98、Se2.07),并测定四种土壤中不同形态硒的含量。芥菜和菠菜于生长40 d、53 d、68 d和82 d后取样,测定蔬菜可食部分硒含量;于生长97 d后收获,分为根部和地上部。大蒜于生长42 d、68 d、82 d、120 d后取样,测定地上部硒含量;于生长165 d后收获,分为根部、鳞茎和叶。测定供试蔬菜总硒含量、有机硒含量,计算不同硒含量土壤上蔬菜对硒的吸收和转化系数。【结果】三种蔬菜中芥菜的生长对土壤硒最为敏感,芥菜可食部位生物量鲜重以Se0.29处理最高,菠菜和大蒜均以Se0.58处理最高,与Se2.07处理均达显著差异。三种蔬菜地上部硒含量在整个生育期总体呈现增加的趋势,不同生育期均表现为大蒜 > 芥菜 > 菠菜。收获期三种蔬菜各部位的硒含量随着土壤硒含量 (0.29~2.07 mg/kg) 的增加而增加,表现为Se2.07 > Se0.98 > Se0.58 > Se0.29,Se2.07处理的菠菜地上部和地下部硒含量分别是其Se0.29处理的8.63倍和7.10倍,芥菜是12.25倍和23.29倍,Se2.07处理大蒜鳞茎和叶部硒含量是Se0.29处理的39.92倍和4.90倍;可食部位硒含量为大蒜 (7.25~289 μg/kg) > 芥菜 (1.22~14.9 μg/kg) > 菠菜 (0.73~6.30 μg/kg),均表现为地下部 > 地上部,Se2.07处理菠菜根部硒含量是茎叶的4.80倍,芥菜是12.06倍,大蒜是8.22倍。在富硒土壤Se0.98和Se2.07处理条件下,大蒜和芥菜能从土壤中富集硒,吸收系数是菠菜的3.06~8.47倍和1.58~5.8倍,均达到了富硒蔬菜标准 (≥ 0.01 mg/kg)。三种蔬菜可食部位有机硒含量占总硒比例为73.5%~84.7%,并随土壤硒含量的增加而增加,其中Se2.07与Se0.29处理差异显著;蔬菜硒含量不但与土壤总硒含量相关,而且与有效态硒含量呈显著正相关。【结论】蔬菜种类和土壤硒含量均影响蔬菜硒的吸收、转化和富集。三种蔬菜对土壤硒的敏感性以芥菜最强。蔬菜硒含量和可食用部位有机硒的转化率均随着土壤硒含量的增加而增加,与土壤总硒含量和有效态硒含量呈显著正相关。富硒能力为大蒜 > 芥菜 > 菠菜,在天然富硒土壤上生长的大蒜和芥菜硒含量易达到富硒蔬菜标准,而菠菜未显示出富硒能力。因此,虽然土壤硒含量高影响了大蒜和芥菜的生长,但大蒜和芥菜具有较强的将硒转移到可食部位的能力,可作为富硒蔬菜生产。  相似文献   

9.
Skins from different hazelnut samples were characterized for total polyphenol content, total antioxidant capacity (TAC), and their content in specific polyphenolic compounds. The main polyphenolic subclass, identified and quantified by means of HPLC-MS/MS, comprised monomeric and oligomeric flavan-3-ols, which accounted for more than 95% of total polyphenols. Flavonols and dihydrochalcones were 3.5% while phenolic acids were less than 1% of the total identified phenolics. The TAC values of the skin samples ranged between 0.6 and 2.2 mol of reduced iron/kg of sample, which is about 3 times the TAC of whole walnuts, 7-8 times that of dark chocolate, 10 times that of espresso coffee, and 25 times that of blackberries. By describing the profile of polyphenols present in hazelnut skins, this study provides the basis to further investigate the potential health effects of hazelnut byproduct.  相似文献   

10.
This work describes the method for total antioxidant capacity (TAC) and/or total content of phenolics (TCP) analysis in wines using microdialysis online-coupled with amperometric detection using a carbon microfiber working electrode. The system was tested on 10 selected wine samples, and the results were compared with total reactive antioxidant potential (TRAP), oxygen radical absorbance capacity (ORAC), and chemiluminescent determination of total antioxidant capacity (CL-TAC) methods using Trolox and catechin as standards. Microdialysis online-coupled with amperometric detection gives similar results to the widely used cyclic voltammetry methodology and closely correlates with ORAC and TRAP. The problem of electrode fouling is overcome by the introduction of an electrochemical cleaning step (1-2 min at the potential of 0 V vs Ag/AgCl). Such a procedure is sufficient to fully regenerate the electrode response for both red and white wine samples as well as catechin/Trolox standards. The appropriate size of microdialysis probes enables easy automation of the electrochemical TAC/TCP measurement using 96-well microtitration plates.  相似文献   

11.
Raw, germinated, popped, and cooked huauzontle (Chenopodium berlandieri spp. nuttalliae) seeds were analyzed for the contents of phenolics extracted with water (WE), methanol, 1:1 (v/v) methanol/water (MWE), and 1.2M HCl in 1:1 (v/v) methanol/water (HMWE); radical scavenging capacity measured by the 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) and 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulphonic acid) (ABTS) methods was studied. The effect of the system solvents used for the accurate quantification of antioxidant content and capacity showed that for raw, germinated, and cooked extracts, water gave the highest yield of total phenolic content, and MWE could recover the highest yield in popped extracts. Thermal treatments increased the flavonoid content more in all extracts than did the germinating process, with values ranging from 10 to 620 μg/g db of quercetin equivalents. However, all treatments significantly decreased (P < 0.05) the total phenolics (from 3,010 μg of gallic acid equivalents/g db in raw seeds WE to 710 μg/g db in germinated seeds MWE). HMWE in all treatments showed the highest values (up to 95.41%) by the DPPH method. With the ABTS method, germinated and popped MWE showed the highest values (up to 2,740mM Trolox/kg db). Based on these results, huauzontle seeds represent a useful potential ingredient for consumer health, because it has been shown to be a good source of total phenolic content having high antioxidant activity; moreover, for further studies, water appears to be effective as an extraction solvent of phenolic compounds.  相似文献   

12.
《Cereal Chemistry》2017,94(2):291-297
Edible beans are among the most important grain legumes consumed by humans. To provide new information on the antioxidant phenolics of edible beans, the antioxidant capacity, total phenolic content (TPC), and total flavonoid content (TFC) in both soluble and bound fractions of 42 edible beans from China were systematically evaluated, with main phenolic compounds identified and quantified in 10 beans possessing the highest TPC. Edible beans contained a wide range of total antioxidant capacity and TPC generally comparable with common grains, fruits, and vegetables, and their bound fractions had significant antioxidant capacity, TPC, and TFC. Red sword bean was found for the first time to show extremely high total antioxidant capacity (ferrous[II] at 235 ± 13.2 μmol/g and Trolox at 164 ± 10.5 μmol/g) and TPC (1767 ± 58.3 mg of GAE/100 g). Phenolic compounds such as catechin, ferulic acid, gallic acid, p‐coumaric acid, and protocatechuic acid were widely detected in selected beans. A positive correlation was found between antioxidant capacity (ferric‐reducing antioxidant power [FRAP] and Trolox equivalent antioxidant capacity [TEAC] values) and TPC, with correlation coefficient r = 0.974 (FRAP value versus TPC) and r = 0.914 (TEAC value versus TPC). Therefore, beans with high antioxidant capacity and phenolic content can be valuable sources of dietary natural antioxidants for the prevention of oxidative stress‐related chronic diseases.  相似文献   

13.
Strawberries were processed to juice, nectar, wine, and puree. For investigation of the antioxidant capacity as well as the contents of ascorbic acid, total phenolics and total anthocyanins, samples were taken after different stages of production to determine the effects of processing. The content of vitamin C was measured spectrophotometrically. The total phenolic content was analyzed by using the Folin-Ciocalteu method, and the amount of total anthocyanins was determined by using the pH-differential method. Two different methods-the trolox equivalent antioxidant capacity assay and the ferric reducing antioxidant power test-were used to determine the hydrophilic antioxidant capacity. This study showed the decrease of all investigated parameters within processing strawberries to different products. The content of ascorbic acid decreased with production time and processing steps, especially during heat treatment. The investigations on total phenolics in strawberry products proved fining to be a mild method to clarify berry juices and wines without removing high amounts of total phenolics. Fermentation did not lead to heavy losses of total phenolics, probably due to polymerization and condensation of monomer phenolics such as anthocyanins. Total anthocyanins and the hydrophilic antioxidant capacity decreased while using high temperatures. Anthocyanins also decreased considerably during the processing of wines, mainly caused by fermentation and pasteurization.  相似文献   

14.
硒硫配施对大蒜的营养效应研究   总被引:11,自引:2,他引:11  
通过不同的施硫水平和硒硫配施的盆栽试验,研究了大蒜的硫(S)营养效应及硒硫(Se-S)交互作用。大蒜收获后,分析测定了蒜头的10种必需营养元素和Se的不同组分以及新鲜蒜头品质(大蒜素、维生素C)。借助SPSS10.0统计软件对大蒜矿质营养进行主成份提取(PCA)和因子分析(FA),通过对蒜头营养品质(大蒜素、硒组分和维生素C)与矿质主因子间的线性模型模拟,从大蒜营养的角度对各矿质主因子进行命名。以矿质营养因子得分为二次变量进行方差分析和不同处理间营养品质的多重比较结果表明,硒硫配施通过对大蒜矿质营养的促进作用而改善了大蒜的营养品质,但对大蒜的风味品质(大蒜素)的影响则表现为随着硫水平的提高而下降。同时还发现,在土壤有效Se、S供应比较充足的条件下,Se、S交互作用在一定的比例范围内(1∶4~8)才表现为正效应。  相似文献   

15.
Antioxidants found in fruits and vegetables play an important role via their protective effects against the onset of aging-related chronic diseases. Our previous research has indicated that unripe ciku fruits (Manilkara zapota L.) are an excellent source of antioxidants, with over 3000 mg of L-ascorbic acid equivalent antioxidant capacity (AEAC) per 100 g of fresh sample. In this study, 24 antioxidants in an extract of ciku king were characterized through a free radical spiking test. Their chemical structures were proposed using high-performance liquid chromatography-mass spectrometry (HPLC-MS) and tandem MS (HPLC/MSn). The antioxidant capacity of ciku king fruits was mainly attributed to polyphenolics with basic blocks of gallocatechin or catechin or both. The changes of total antioxidant capacity (TAC) and total phenolics content (TPC) of ciku king fruits with storage time were also investigated. It was found that the TAC and TPC decreased significantly as the fruits gradually changed from the unripe to the overripe stage. The best time for one to consume ciku king fruits at a flavorful stage with high amounts of antioxidants with AEAC values ranging from 600 to 1200 mg per 100 g fresh sample is suggested. The change of the content of major antioxidant peaks was also consistent with changes of antioxidant levels during storage.  相似文献   

16.
Dent, flint, and specialty genotypes of Indian yellow maize were evaluated for phytochemical content and their hydrophilic antioxidant capacity. Solid‐phase extraction coupled with solid–liquid extraction was used to obtain free phenolics and flavonoids from maize samples, reducing the use of excessive solvents and handling time. Bound phenolics were extracted with enhanced acidic hydrolysis to improve extractability. The phenolic contents in Indian maize genotypes ranged from 46 to 79 μmol of ferulic acid equivalents per gram of sample on a dry basis (db). Carotenoids in Indian maize genotypes were found to be equivalent to Chinese yellow maize and ranged from 13 to 24 μg/g of sample (db), whereas tocol content varied greatly in the range of 607–1,238 μg of α‐tocopherol equivalents/g of sample (db). Dent and flint corn did not exhibit differences (P > 0.05) in their phenolic contents, whereas among the specialty genotypes sweet corn contained the highest phenolics but least carotenoids (P < 0.05). Bound extracts appeared to contribute largely to 2,2′‐diphenyl‐1‐picrylhydrazyl free radical scavenging, hydrogen peroxide scavenging, and ferric reducing antioxidant power of maize genotypes. Sweet corn exhibited higher antioxidant capacity (P < 0.05) among all the genotypes. The antioxidant capacities correlated well with the total phenolic contents of the maize genotypes.  相似文献   

17.
Fresh strawberries (Fragaria x ananassa Duch.), raspberries (Rubus idaeus Michx.), highbush blueberries (Vaccinium corymbosum L.), and lowbush blueberries (Vaccinium angustifolium Aiton) were stored at 0, 10, 20, and 30 degrees C for up to 8 days to determine the effects of storage temperature on whole fruit antioxidant capacity (as measured by the oxygen radical absorbing capacity assay, Cao et al., Clin. Chem. 1995, 41, 1738-1744) and total phenolic, anthocyanin, and ascorbate content. The four fruit varied markedly in their total antioxidant capacity, and antioxidant capacity was strongly correlated with the content of total phenolics (0.83) and anthocyanins (0.90). The antioxidant capacity of the two blueberry species was about 3-fold higher than either strawberries or raspberries. However, there was an increase in the antioxidant capacity of strawberries and raspberries during storage at temperatures >0 degrees C, which was accompanied by increases in anthocyanins in strawberries and increases in anthocyanins and total phenolics in raspberries. Ascorbate content differed more than 5-fold among the four fruit species; on average, strawberries and raspberries had almost 4-times more ascorbate than highbush and lowbush blueberries. There were no ascorbate losses in strawberries or highbush blueberries during 8 days of storage at the various temperatures, but there were losses in the other two fruit species. Ascorbate made only a small contribution (0.4-9.4%) to the total antioxidant capacity of the fruit. The increase observed in antioxidant capacity through postharvest phenolic synthesis and metabolism suggested that commercially feasible technologies may be developed to enhance the health functionality of small fruit crops.  相似文献   

18.
为探究采前喷施脱落酸(ABA)对欧李果实品质的影响,本研究选择农大6号和农大7号2个欧李品种为试验材料,在喷施不同浓度和不同次数的ABA后测定成熟果实的单果重、可溶性固形物含量、可滴定酸含量、类黄酮含量、总酚含量以及抗氧化能力。结果表明,喷施不同浓度和不同次数的ABA后,农大6号欧李果实可滴定酸含量、类黄酮含量、总酚含量以及抗氧化能力降低,对于可滴定酸含量而言,喷施2次比喷施1次的降酸效果明显,而类黄酮含量、总酚含量以及抗氧化能力受ABA浓度和喷施次数的变化影响不大。各处理下农大7号欧李果实的单果重和可溶性固形物含量均得到了升高,类黄酮含量、总酚含量以及抗氧化能力受ABA浓度和喷施次数的变化影响较大。根据主成分分析进行排名可知,不同浓度不同次数的脱落酸处理后农大6号欧李果实综合评分均低于对照,果实综合品质下降,农大7号欧李果实综合评分均高于对照,当脱落酸浓度为25 mg·L-1,喷施次数为1次时对果实综合品质的提升效果最好。本研究为提升欧李果实品质选取喷施适宜浓度和次数的ABA提供了理论基础。  相似文献   

19.
This study was conducted to investigate the antioxidant vitamin C, the polyphenol content, and the hydrophilic antioxidant capacity of tomato juice, baked tomatoes, tomato sauce, and tomato soup. During the production of tomato juice and during the preparation of the other tomato products, samples were taken after different times, respectively, after each particular production step. High-performance liquid chromatography was used to determine the content of vitamin C. The total phenolics content was analyzed spectrophotometrically by using the Folin-Ciocalteu method. The hydrophilic antioxidant capacity was measured by using three different methods: the Trolox equivalent antioxidant capacity assay, the ferric reducing antioxidant power test, and the photochemiluminescence assay. The vitamin C contents of the tomato products decreased during the thermal processing of tomatoes. In contrast, the total phenolics concentration and the water soluble antioxidant capacity increased.  相似文献   

20.
为明确多层包膜控释掺混肥在农业生产中的应用效果,通过田间试验研究了其对大蒜鳞茎、蒜薹产量,不同器官养分吸收及土壤速效养分状况的影响。在总养分减量10%的条件下,多层包膜控释掺混肥处理较当地常规处理的蒜薹和鳞茎产量分别提高了32.74%和10.61%,较单层包膜控释掺混肥处理蒜薹产量提高了23.22%,同时能够提高土壤速效氮含量,收获期土壤硝态氮、铵态氮含量较单层包膜控释掺混肥处理分别提高23.79%和5.79%。在总养分减量30%条件下,多层包膜控释掺混肥处理大蒜鳞茎中氮含量较单层包膜控释掺混肥处理提高了6.67%,差异显著,并促进了鳞茎中磷素积累,减轻了养分胁迫状态下养分向地上部积累的效应。经济效益分析表明,在总养分减量10%条件下,施用多层包膜控释掺混肥的净收益较单层包膜控释掺混肥提高6.83%,因此,多层包膜控释掺混肥在农业生产中具有广阔的应用前景。  相似文献   

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