共查询到20条相似文献，搜索用时 31 毫秒
1.
Selenium-enriched green tea leaves were prepared by foliar applications of selenium-amended fertilizer during autumn season. The influence of selenium (Se) on preservation quality of tea during 4-month storage was determined. The results showed that the Se and vitamin C contents of green tea were significantly increased by selenium spraying during the autumn tea-producing season. The vitamin C content of Se-enriched green tea was higher and its decline was significantly slower during storage compared to normal green tea. However, there was no significant difference between the contents of chlorophyll and polyphenol of Se-enriched and regular tea. During the first 60 days, the color of green tea extract in Se-enriched green tea and normal tea showed no significant difference. However, the color of green tea extract in Se-enriched green tea was more stable compared with normal tea during the storage period. The sweetness and aroma of extracts of Se-enriched green tea were also significantly higher than that of normal tea and the bitterness of extracts of Se-enriched green tea was significantly lower compared with normal tea. These results showed that selenium application can slow the reduction of tea's major component and thus improve preservation qualities of green tea. 相似文献
2.
Effect of selenium on increasing the antioxidant activity of tea leaves harvested during the early spring tea producing season 总被引：6，自引：0，他引：6
This research was to determine the effect of foliar application of selenium on increasing the antioxidant activity of tea harvested during the early spring tea producing season using a alpha,alpha-diphenyl-beta-picrylhydrazyl (DPPH) radical scavenging method and the linoleic acid system. The results showed that the radical scavenging ability of the tea extracts followed this order during the first 60 min: selenium-enriched tea obtained by fertilization with selenate > BHT > selenium-enriched tea obtained by fertilization with selenite > alpha-tocopherol > regular tea. Se-enriched tea obtained by fertilization with selenate exhibited the highest inhibition percentage of 84.29% at 30 min. Se-enriched tea extracts provided higher hydrogen-donating capabilities than regular tea and contrasts with BHT and alpha-tocopherol at the concentration of 100 microg of solids/mL of ethanol. There was a little change in the sequence of radical scavenging ability during the later 60 min: Se-enriched tea obtained by fertilization with selenate > Se-enriched tea obtained by fertilization with selenite > BHT > regular tea > alpha-tocopherol. The individual activity of tea extracts and references measured by the linoleic acid system showed that the tea extracts, BHT, and alpha-tocopherol manifested almost the same patterns of activity as the DPPH method. Tea enriched in selenium by fertilization with selenate still exhibited the highest inhibition activity of lipid oxidation, whereas alpha-tocopherol showed the lowest inhibition. The antioxidant activity of Se-enriched green tea harvested during the early spring tea producing season is enhanced compared to regular tea. 相似文献
3.
采用温室大棚试验,研究了叶面喷施硒酸钠和亚硒酸钠对提高草莓硒含量的影响以及硒在草莓植株中的转运和分布,旨在为富硒水果的开发和生产提供理论依据。本试验在草莓初花期进行叶面喷施亚硒酸钠和硒酸钠,当喷硒量为20、40、60 g Se·hm~(-2)时,亚硒酸钠处理40 d后草莓果实样品中硒含量分别为0.03、0.10、0.15 mg·kg~(-1)FW,分别为对照的3、20倍和30倍;硒酸钠处理40d后草莓果实硒含量分别为0.05、0.12、0.17 mg·kg~(-1) FW,是对照处理的5、24倍和34倍。但是叶面喷施的硒持续供给果实的能力有限,随着草莓果实的连续生长,后期采收的草莓中硒含量显著下降。叶面喷硒后,叶片吸收的亚硒酸钠约有30%转移到了根部,而硒酸钠则更多地累积于叶片中,转移到根部的量不到15%。草莓初花期叶面喷施硒可以显著提高前期草莓果实中硒的含量,随着采收期的延长,草莓中硒的含量显著下降,喷施亚硒酸钠的处理硒向根部转移的能力高于硒酸钠的处理。 相似文献
4.
Both selenium and green tea have been shown to have potential antitumor effects. Here we have investigated the anticarcinogenic effect of the selenium-enriched green tea extract (Se-TE) in a Kunming mice model transplanted with human hepatoma cells HepG2. Mice were assigned to 8 groups consisting of 10 mice each after tumor cell inoculation. The control group received only water, whereas the remaining groups received regular green tea extract (RT), Se-TE which was produced by fertilization with selenite on tea leaves, selenite, and RT + selenite. After the mice were fed intragastrically with these agents for 8 days, tumor growth in RT-, Se-TE-, and selenite-fed mice was significantly suppressed, compared with that in control mice (P < 0.001). Supplementation with Se-TEs and selenite was able to elevate mice blood and liver Se concentrations, but did not significantly enhance selenoprotein glutathione peroxidase and other antioxidant enzyme superoxide dismutase activity in mice blood and liver. These results suggest that the antitumor function of Se-TEs may be attributed to the oxidative stress induced by selenium and green tea components in a suitable selenium supplementation pathway. 相似文献
5.
【目的】探究在茶树不同生育时期叶面喷施不同硒肥对夏茶产量、品质及硒含量的影响,为生产富硒茶提供技术依据。【方法】田间试验在浙江嵊州进行,供试茶树品种为‘中茶108’。试验采用二因素列区设计,主处理为硒肥种类(A因素),副处理为硒肥喷施时期(B因素)。主处理设喷施清水对照(A0)、硒酸钠(A1)、亚硒酸钠(A2)和酵母硒(A3);副处理设夏茶顶芽萌发前(5月12日,B1)与1芽1叶期(5月20日,B2)两个喷施时期。硒肥喷施浓度均为Se 50 mg/L,硒肥溶液喷施量为1.8 L/m2。当茶树蓬面1芽2叶占比达30%左右时,每个小区随机选取30 cm×30 cm茶蓬,调查蓬面新梢总数、1芽2叶数量、1芽2叶长度和百芽重。同时,取1芽2叶新梢样品,测定茶多酚、儿茶素、咖啡碱、游离氨基酸、花青素以及硒含量。【结果】与A0B1处理相比,A3B1处理茶树萌展值显著降低了0.14,但对茶树蓬面新梢总数无明显影响;A2B1处理茶树1芽2叶新梢长度和百芽重分别显著降低了1.04 cm和1.94 g。A1B2和A3B2处理茶树蓬面新梢总数分别显著降低了17.66和22.33,但不影响其萌展值;A1B2显... 相似文献
6.
Poggi V Arcioni A Filippini P Pifferi PG 《Journal of agricultural and food chemistry》2000,48(10):4749-4751
The effect of a foliar spray of selenium on potatoes was investigated for 2 years. Amounts of 0, 50, and 150 g of Se ha(-)(1) were applied both as sodium selenate and as sodium selenite in water, either pure or with the addition of 0.15% of soluble leonardite as a source of humic acids (pH 7). Tuber selenium concentration increased with the application levels, both with sodium selenate and with sodium selenite, when only aqueous solutions were used. When humic acids were added, the tuber selenium level rose more markedly after the application of sodium selenate as compared to the case of the aqueous solutions; however, in the case of sodium selenite, the level showed a large increase only after the application of 50 g of Se ha(-)(1). Kinetics showed that humic acids raised the selenate availability, but no differences were found in the distribution of selenium in the tuber fractions. Foliar application of selenium with humic acids was proven to be a good way to increase the selenium content of potatoes, but the assimilation process of selenium was simpler with selenate than with selenite. 相似文献
7.
Determination of selenium concentration of rice in china and effect of fertilization of selenite and selenate on selenium content of rice 总被引：1，自引：0，他引：1
Chen L Yang F Xu J Hu Y Hu Q Zhang Y Pan G 《Journal of agricultural and food chemistry》2002,50(18):5128-5130
A method of hydride generation atomic fluorescence spectrometry was applied to the determination of the selenium concentration of regular polished rice in China and selenium-enriched polished rice obtained by foliar application of selenium-enriched fertilizer in the forms of selenite and selenate. The average selenium content of regular rice was 0.025 +/- 0.011 microg g(-)(1). On the basis of a daily dietary rice intake of 300-500 g suggested by the China Nutrition Society, the total selenium intake from regular rice was calculated to be 7.5-12.5 microg per person per day for an adult. The selenium contents of rice were significantly increased to 0.471-0.640 microg g(-)(1) by foliar application of selenium-enriched fertilizer at rate of 20 g of Se ha(-)(1) in the forms of sodium selenite and sodium selenate. The selenium content of rice by application of a fertilizer of selenate was 35.9% higher than that by a fertilizer of selenite, which showed that Se-enriched fertilizer in selenate exhibited greater efficiency in increasing Se content in rice products. The Se-enriched rice products can increase daily Se intake on average by 100-200 microg of Se per day by the consumption of 400 g of rice products if the Se level of rice products is controlled at 0.3-0.5 microg of Se g(-)(1). Because rice is a staple food in China, selenium-enriched rice obtained by bioenrichment of selenium to increase the Se content of rice could be a good selenium source for the population in selenium-deficient regions. 相似文献
8.
用盆栽试验研究了不同浓度外源硒（四价和六价）处理土壤对小麦生长和生理代谢的影响,旨在为富硒小麦的种植和开发提供理论依据。结果表明：外源硒抑制了苗期小麦的生长（株高和生物量）;而在生长后期,随外源硒浓度增加表现为先促进后抑制作用。Se（Ⅳ）和Se（Ⅵ）处理对小麦生物量影响的EC10分别从苗期的1.40mg·kg-1和0.28mg·kg-1增加到收获期的28.48mg·kg-1和4.56mg·kg-1,表明小麦对硒的耐受浓度随生长时间的延长逐渐增大。Se（Ⅵ）低浓度（≤1mg·kg-1）对小麦生长的促进作用及高浓度（≥2.5mg·kg-1）对小麦生长的抑制作用均大于Se（Ⅳ）。小麦籽粒产量随外源Se（Ⅳ）和Se（Ⅵ）浓度的增大先升高而后降低,分别在2.5mg·kg-1和1mg·kg-1浓度处理时达到最大。低浓度硒处理（Se（Ⅳ）≤5mg·kg-1和Se（Ⅵ）≤0.5mg·kg-1）能促进拔节期小麦叶片中GSH和POD等抗氧化酶活性,显著降低叶片过氧化物质MDA（Se≤2.5mg·kg-1）含量,高浓度硒处理则与之相反。 相似文献
9.
通过田间试验,研究了不同形态叶面硒肥对水稻吸收和转运硒的影响。与空白对照相比,亚硒酸钠、硒酸钠、硒代蛋氨酸和化学纳米硒在水稻扬花期一次施用(15g/hm2)可使水稻籽粒、颍壳和秸秆的硒含量分别提高0.06～0.64、0.36～0.83和0.32～0.75 mg/kg。籽粒硒的回收率大小顺序为：硒代蛋氨酸(34.6%)>亚硒酸钠(15.7%)>硒酸钠(15.0%)>化学纳米硒(6.6%);硒在水稻各部位中的分配比例的高低顺序为：秸秆>籽粒>颍壳。此外,硒用量与水稻籽粒的硒含量呈极显著线性相关。按照黑龙江省富硒大米的地方标准(DB23T 790—2004),达到一等大米的硒含量指标(0.20～0.30 mg/kg),亚硒酸钠单施的施用量为6.01～10.62 g/hm2,腐植酸+亚硒酸钠复合肥的施用量为4.26～8.63 g/hm2。硒代蛋氨酸的富硒效率高于其他3种硒形态,腐植酸+亚硒酸钠复合肥的富硒效率高于亚硒酸钠单施。 相似文献
10.
《Communications in Soil Science and Plant Analysis》2012,43(11):1362-1375
Selenium (Se) is an essential nutrient for humans and is beneficial for plant growth. To investigate the transformation and bioavailability of Se in tobacco planting soil, selenite and selenate were applied. A pot experiment and sequential extraction scheme were used to investigate the Se contents in different forms in soils treated with Se. A series of equations were applied to model the transformation behavior of Se in this study. The results showed that the forms of selenium were increased significantly by applying the different valence state of water-soluble selenium. The carbonate-bound and iron-manganese (Fe-Mn) oxide–bound species were improved in selenite-added soil, whereas the soluble and exchangeable forms were increased in selenate-added soil. Michaelis-Menten equation fitting results indicated that estimated maximal selenium contents of leaves, stems, and roots in selenate-added soils were 1.83, 15.81, and 20.98 times larger than in selenite-added soils. The utilization levels of selenate were 4.3 to 7.9 times larger than selenite for Nicotiana tabacum L. In conclusion, the bioavailability and mobility of selenate were greater than selenite in Nicotiana tabacum L. planting soil. 相似文献
11.
有机肥与控释复合肥配施对茶叶产量、品质和土壤化学性质的影响 总被引：1，自引：0，他引：1
合理施肥对于提高茶叶产量和品质具有重要作用。通过3年田间试验,对比研究了6种施肥模式（常规化肥、控释复合肥、常规化肥 + 有机肥、控释复合肥 + 有机肥、70%常规化肥 + 有机肥、70%控释复合肥 + 有机肥）对茶叶产量、品质和土壤化学性质的影响。结果表明,一次性施用茶树专用控释复合肥能够达到常规化肥1年4次施用的增产效果,并显著提高了夏茶茶叶品质。与单施常规化肥相比,增施有机肥处理的茶叶产量提高10.6% ~ 14.0%,达显著水平（P < 0 .05),净收益增加8.0% ~ 18.3%,并显著提高了茶叶水浸出物和游离氨基酸总量,降低茶多酚含量和酚氨比。与常规化肥增施有机肥相比,控释复合肥增施有机肥茶叶产量提高了3.0%（P < 0.05),净收益增加7.6% ~ 8.5%,夏茶水浸出物含量提高1.34% ~ 1.39%,茶多酚含量降低了2.7% ~ 4.7%,达显著水平（P < 0.05)。70%常规化肥 + 有机肥或70%控释复合肥 + 有机肥处理的茶叶产量及品质与全量施肥增施有机肥处理相比均无显著性差异。在培肥土壤方面,增施有机肥处理显著提高了茶园0 ~ 20?cm土层土壤pH、有机质、全氮和速效氮含量。因此,从施肥方便性、茶叶产量、经济效益、茶叶品质和培肥土壤方面综合考虑,与施用常规化肥相比,控释复合肥减少用量30%并增施有机肥是最优推荐施肥措施。 相似文献
12.
《Communications in Soil Science and Plant Analysis》2012,43(22):3465-3482
In soil, adsorption of selenium (Se) onto mineral surfaces is accompanied by poorly known retention via organic matter. The effects of these components on the availability of Se were examined in two pot experiments. Spring wheat was grown with increasing amounts of selenate (SeO4 2–) in one sand and three peat soils, and ryegrass with selenate and selenite (SeO3 2–) in sphagnum peat manipulated by iron (Fe) hydroxide. Selenate persisted in soluble form, whereas selenite was fixed in the soil. In wheat, 5–50% of the selenate addition was recovered in the plant, the proportion increasing with increasing Se. In ryegrass, 30–40% of the added selenate but less than 2% of the selenite was found within the leaves. The Fe hydroxide enrichment enhanced the selenite uptake. Phosphate buffer desorbed a minor proportion of the added selenite, except in peat amply enriched with Fe hydroxide. The results suggest that the retention mechanism of selenite was changed due to the hydroxide amendment. 相似文献
13.
适宜氮肥施用量显著提升夏季绿茶品质 总被引：2，自引：1，他引：1
14.
以紫甘薯为试验材料,采用盆栽试验的方法研究了基施硒酸钠[Se(VI)]和亚硒酸钠[Se(IV)]条件下,紫甘薯对外源硒的吸收累积规律,并比较了施用两种不同价态硒的紫甘薯富硒效果。结果表明:两种硒源均可显著提高紫甘薯各器官含硒量,且紫甘薯含硒量均随施硒量的增加而增大。当土壤施硒量为Se 8 mg/kg时,施用硒酸钠、亚硒酸钠收获期薯块的硒含量(干基)分别达到6.69、0.88 mg/kg。紫甘薯生育期40 d时各器官硒含量叶茎薯块,130 d时硒含量叶薯块茎。当硒酸钠施用量为Se 4 mg/kg时,紫甘薯薯块中的硒累积量最高达923.81μg/株,硒在紫甘薯块根中的分配率可达67%~70%,硒酸钠处理下,紫甘薯对硒的吸收利用率远远高于亚硒酸钠处理。综合紫甘薯含硒量和施硒量对生长的影响结果分析,施用硒酸钠和亚硒酸钠均能增加紫甘薯薯块的硒含量,紫甘薯对硒酸钠敏感性高于亚硒酸钠,生产过程中应充分考虑施用硒酸钠对作物造成的毒害。 相似文献
15.
Rama V. Srikanth Lavu Veerle De Schepper Kathy Steppe Prasad N. V. Majeti Filip Tack Gijs Du Laing 《植物养料与土壤学杂志》2013,176(4):634-639
Due to selenium (Se) deficiency, Se fortification of food and feed is applied in many countries. Therefore, potential use of Se‐enriched kenaf was investigated based on its Se accumulation, its potential to transform accumulated Se to other Se species, and effect of Se accumulation on its growth. Kenaf was grown with different levels of two Se fertilizers (selenite and selenate) at concentrations ranging from 0 to 4 mg Se (kg soil)–1. Total Se concentrations in the plants grown on selenate‐treated soil amounted to (1019 ± 136) mg Se (kg dry weight)–1 and were much higher compared to plants grown on selenite‐treated soil. Identified Se species were selenite, selenate, Se‐methionine, and Se‐cystine. Biomass yield, net photosynthesis, and chlorophyll index of the plants decreased when plants were grown on soils treated with high doses of selenate. 相似文献
16.
不同茶树品种(系)的绿茶滋味分析及评价模型构建 总被引：1，自引：3，他引：1
为客观准确地评价不同茶树品种(系)绿茶的滋味品质,该研究系统分析了25个茶树品种(系)绿茶的主要滋味成分含量及其Dot值,利用主成分分析法对不同茶树品种(系)绿茶滋味品质进行综合评价并建立滋味品质评价模型。结果表明:儿茶素、咖啡碱是不同茶树品种(系)绿茶苦涩味强度差异的主要原因,其中表没食子儿茶素没食子酸酯(Epigallocatechingallate,EGCG)是所测样品中涩味的主要贡献物质,EGCG和咖啡碱为所测样品中苦味的主要贡献物质。氨基酸是不同茶树品种(系)绿茶鲜味、甜味差异主要因素,谷氨酸是所测样品中鲜味的主要贡献物质。主成分分析表明:前5个主成分的累计方差贡献率为79.018%,并以前5个主成分的线性回归方程和贡献率构建了滋味品质评价模型,模型评价结果与感官审评结果较为相似,存在极显著相关性(P0.01),相关系数为0.791;利用模型中各主成分的得分,能够较好的区分所测样品的苦、涩、鲜、爽等滋味特征。因此,该研究所建模型能够较好的评价所测样品的滋味品质及其主要滋味特征的差异,为各茶树品种(系)的推广应用提供理论依据,也为不同茶树品种(系)绿茶滋味品质的科学评价提供新的思路和方法。 相似文献
17.
为了明确叶面喷施亚硒酸钠对黑豆硒吸收转运特征及籽粒硒形态的影响,采用小区试验在黑豆结荚兴盛期进行一次性叶面喷施亚硒酸钠(施硒量分别为0、6、12、18和24 mg·m-2)处理,分析比较不同浓度亚硒酸钠处理下黑豆产量、各器官硒含量、籽粒有机硒转化率和品质性状的差异。结果表明,各施硒水平对黑豆各器官总硒含量均有提升作用,在24 mg·m-2硒处理时各器官总硒含量最大,根、茎、荚和籽粒硒含量分别较对照提高了8.74、8.37、9.85和65.21倍,硒处理后各器官总硒含量呈现籽粒>根≈荚>茎的特点。籽粒中硒以有机硒形态存在,且有机硒转化率随着亚硒酸钠浓度的增加呈下降趋势,在0、6、12、18和24 mg·m-2施硒处理时,有机硒含量分别为0.071 4、1.101 8、1.510 6、1.811 1和2.093 5 mg·kg-1,有机硒转化率分别为94.52%、84.81%、70.30%、60.11%和52.43%。叶面喷施亚硒酸钠显著提高了黑豆籽粒蛋白质含量和分离蛋白硒含量,但对脂肪含量的影响较小,在24 mg·m-2硒处理时蛋白质含量和分离蛋白硒含量分别较对照增加了2.4个百分点和117.35倍,分离蛋白硒含量占有机硒和总硒含量的比例分别为90.29%和47.39%。适宜浓度亚硒酸钠叶面喷施对黑豆产量具有促进作用,但浓度过高导致增产效果减弱。综上,叶面喷施亚硒酸钠可提高黑豆各器官总硒含量,但黑豆籽粒有机硒转化率随喷施浓度的增加呈下降趋势,且黑豆籽粒有机硒主要以蛋白质形式存在。本研究结果为应用外源硒强化技术生产富硒黑豆提供了科学依据。 相似文献
18.
利用盆栽试验,研究了不同浓度、不同价态外源硒（Se4＋、Se6＋）对连续种植小白菜土壤中过氧化氢酶、脱氢酶、脲酶和碱性磷酸酶活性的影响,为土壤硒污染的生态风险评价和管理提供科学依据。结果表明：低浓度硒对土壤酶活性有不同程度的激活效应,而高浓度硒对4种土壤酶均产生抑制作用;外源硒对脲酶及脱氢酶活性的抑制作用大于碱性磷酸酶和过氧化氢酶。外源Se4＋及Se6＋浓度与土壤脲酶活性间都存在显著的负相关（P〈0.01）,且同浓度两个价态硒差异显著（P〈0.05）,说明脲酶可作为土壤硒污染程度的生态风险评价的生物指标;而过氧化氢酶、脱氢酶及碱性磷酸酶只能表征一定时间段内土壤硒污染的程度。土壤酶的ED5（0生态剂量）均随硒施入时间的延长而增大,以脲酶的ED50值最小,Se6＋的ED50小于Se4＋,生态毒性大于Se4＋。 相似文献
19.
阐述了植物对不同形态硒的吸收、转运和形态转化机制。植物主要吸收水溶性硒,包括部分有机硒、硒酸盐和亚硒酸盐。多数研究表明植物对硒酸盐的主动吸收是通过高亲和力的硫酸盐转运子完成,最近的研究表明磷酸盐可以调节亚硒酸盐的吸收,磷酸盐转运子在亚硒酸盐的主动吸收过程中有重要作用;植物吸收的硒酸盐很快从根部转移到地上部,在叶片中被还原成亚硒酸盐,进而转化为有机硒化物进入其他组织;而亚硒酸盐及其代谢产物主要积累在根部,极少转移到地上部。进入植物体中的硒转化为含硒氨基酸和硒蛋白参与植物的代谢。 相似文献