共查询到20条相似文献，搜索用时 281 毫秒
1.
The lipase activities in the three main Chinese castor bean varieties [ZiBi 05 （ZB 5）,TongBi 06 （TB 6）,JinBi 02 （JB 2）] were investigated.Two lipases were found in extracts from the endosperms of all the three varieties.One lipase is located in the lipid bodies,showing higher activity at pH 4.5 and exhibiting the highest activity at day 1 of germination.The other lipase is located in the particulates,showing higher activity at pH 9.5 and particularly active at day 4 of germination.The lipid bodies from ZB 5 show the highest lipase activity at day 1 and pH 4.5 among the three varieties during the 8 d of germination.The acid lipase located in the lipid bodies of ZB 5 of germination 1 d was purified to homogeneity by DEAE-sepharose CL-6B and butyl-sepharose CL-4B chromatography after isolation,delipidation and solubilization,with a purification factor of 16.1 and overall activity recovery of 17.7%.The characterizations （such as optimum pH,pH stability,optimum temperature,thermal stability,effect of metal ions,organic solvents stability,substrate specificity） of the purified acid lipase were conducted in detail.A combination of the characterized properties may make this enzyme a useful biocatalyst for industrial application. 相似文献
2.
WILLIAMS R.A. SELOMULYA C. JIA X. 《浙江大学学报(A卷英文版)》2005,6(12):1367-1373
INTRODUCTION Separation of solids from suspending liquid plays a crucial role in a variety of processes, from nanomaterials synthesis to bio-processing. It often involves colloidal particles that need to be aggregated into more manageable sizes. Characteristics of these aggregates influence downstream solids recovery. For instance, aggregates with open configurations may settle slower than those with denser structures due to increasing fluid drag, although considerable flow- through could… 相似文献
3.
Engin 《扬州职业大学学报》2005,(2)
e essence of sound, this paper discusses where the noises of the punch pressing machines mainly come from and their transmission methods. Furthermore, it discusses how to effectively control these noises.noise; punch pressing machine; impact; control0鄂州大学学报J 相似文献
4.
《铜仁师专学报》2001,3(1):29-33,66
Teh Purpose of the teaching and the learning of English is to develop communicative competence.Pragmatics is one of the most essential parts of the communicative competence .It concerns the appropriate use of language.This paper aims to show the significant role of pragmatics in the teaching and learning of English and further explores the importance of cultivating students‘awareness to improve their pragmatic ability and communicative competence。 相似文献
5.
The purposeof the teaching and the learning of English is to develop communicative competence. Pragmatics is one of the most essential parts of the communicative competence .It concerns the appropriate use of language. This paper aims to show the significant role of pragmatics in the teaching and learning of English and further explores the importance of cultivating students' awareness to improve their pragmatic ability and communicative competence. 相似文献
6.
苏秋芳 《福建教育学院学报》2001,2(4):42-44
In poetry, the device of ending two or more lines with words that sound alike is called end
rhyming;end words that share a particular sound are end rhymes. When used in a poem,end rhymes set
up a definite pattern of sounds-a rhyme scheme. 相似文献
7.
The e-book has many advantages over a paperbased product. You can store lots of books on one computer—in fact your entire library could be stored on the top of your desk. E-books also allow you to mark your page with an electronic bookmark and jump straight to it when you open the book. 相似文献
8.
INTRODUCTIONAsasinkandaninnersourceofnutrients,sedimentsplayanimportantroleinlakeeutroph ication.TheeutrophicationstatusofWestLakeisstillcriticalinrecentyearsevenaftermostpollutionsourcesaroundWestLakehavebeencontrolled(Peietal.,1998) ,mainlythroughtherel… 相似文献
9.
Ulrich Teichler 《Higher Education》2008,56(3):349-379
Debates and policies in Europe as regards the diversity of higher education institutions and programmes have changed substantially
over the years. When expansion of the rate of new entry students was expected to grow beyond 10%, diversification between
types of higher education institutions became the most popular option, whereas no consensus emerged as far as the extent of
diversity and the most desirable classifications are concerned. In the 1980s, attention shifted gradually towards “vertical”
differences among institutions of formally the same type. Since the 1990s, more extreme modes of vertical diversity were more
frequently advocated as options to embark into world-wide competition for “world-class university”. The concurrent popular
debates are criticized as blaming moderate vertical inter-institutional diversity, emphasis on intra-institutional diversity,
efforts to put prime emphasis on a variety of profiles of any model other than extreme vertical diversity as counteracting
“quality”, although evidence for the superiority of the model praised is feeble. 相似文献
10.
The e-book has many advantages over a paper-based product. You .can store lots of books on one computer-in fact your entire library could be stored on the top of your desk. E-books also allow you to mark your page with an electronic bookmark and jump straight to it when you open the book. 相似文献
11.
研究CaCl2浸种处理对NaCl胁迫下鸡冠花种子萌发的缓解效应。结果表明,NaCl胁迫抑制了鸡冠花的萌发和生长,NaCl浓度高于100mmol/L时,抑制作用显著加强;较低浓度的CaCl2浸种能缓解鸡冠花种子受到的盐胁迫伤害,而浓度过高,缓解作用减弱甚至消失;试验中CaCl2以80mmol/L的浸种效果最好,在各种浓度盐胁迫下,均能提高种子的发芽率、发芽指数、活力指数,促进胚轴和胚根的生长。适宜浓度的CaCl2浸种能够缓解盐胁迫对鸡冠花种子萌发和生长的抑制作用。 相似文献
12.
NaCl胁迫对鸡冠花和金盏菊种子发芽特性的影响 总被引：1，自引：0，他引：1
以鸡冠花、金盏菊两种花卉种子为试验材料,研究不同浓度NaCl溶液（0、50、100、150、200、250mmol/L）胁迫下种子发芽率、相对发芽率、发芽势、主根长、下胚轴长、侧根长、幼芽叶绿素含量及根系活力等相关指标的变化规律.试验结果表明：鸡冠花种子在NaCl浓度≤100 mmol/L时,各指标与对照差异不显著,说明鸡冠花对低浓度盐胁迫有一定适应性,而高浓度的盐胁迫对其有很强抑制作用;随着NaCl浓度升高,金盏菊各项测量指标均受到一定程度抑制.说明不同露地花卉种子在发芽期的耐盐力表现出明显的差异,且鸡冠花耐盐能力显著强于金盏菊. 相似文献
13.
“吸湿—回干”处理对潍县萝卜陈种子活力的影响研究 总被引：2，自引：0，他引：2
以自然条件贮藏3年的潍县萝卜陈种子为试材,研究了"吸湿—回干"处理对潍县萝卜陈种子活力的影响。结果表明:适当的"吸湿—回干"处理能显著提高潍县萝卜陈种子的发芽势、发芽指数、活力指数、幼苗根长和芽长,但对发芽率影响不大。本试验以浸种6h后回干处理效果最好,潍县萝卜陈种子活力最高。 相似文献
14.
Soybean (Glycine max (L.) Merrill) is a salt-sensitive crop, and its production is severely affected by saline soils. Therefore, the response
of soybean seeds to salt stress during germination was investigated at both physiological and proteomic levels. The salt-tolerant
cultivar Lee68 and salt-sensitive cultivar N2899 were exposed to 100 mmol/L NaCl until radicle protrusion from the seed coat.
In both cultivars, the final germination percentage was not affected by salt, but the mean germination times of Lee68 and
N2899 were delayed by 0.3 and 1.0 d, respectively, compared with controls. In response to salt stress, the abscisic acid content
increased, and gibberellic acid (GA1+3) and isopentenyladenosine decreased. Indole-3-acetic acid increased in Lee68, but remained unchanged in N2899. The proteins
extracted from germinated seeds were separated using two-dimensional gel electrophoresis (2-DE), followed by Coomassie brilliant
blue G-250 staining. About 350 protein spots from 2-DE gels of pH range 3 to 10 and 650 spots from gels of pH range 4 to 7
were reproducibly resolved, of which 18 protein spots showed changes in abundance as a result of salt stress in both cultivars.
After matrix-assisted laser desorption ionization-time of flight-mass spectroscopy (MALDI-TOF-MS) analysis of the differentially
expressed proteins, the peptide mass fingerprint was searched against the soybean UniGene database and nine proteins were
successfully identified. Ferritin and 20S proteasome subunit β-6 were up-regulated in both cultivars. Glyceraldehyde 3-phosphate
dehydrogenase, glutathione S-transferase (GST) 9, GST 10, and seed maturation protein PM36 were down-regulated in Lee68 by salt, but still remained at
a certain level. However, these proteins were present in lower levels in control N2899 and were up-regulated under salt stress.
The results indicate that these proteins might have important roles in defense mechanisms against salt stress during soybean
seed germination. 相似文献
15.
采用培养皿发芽法,研究了水杨酸浸种对盐胁迫下西瓜种子萌发和幼苗生长的影响。结果表明,300mmol/L NaCl溶液浸种显著降低了西瓜种子的发芽率、发芽势、发芽指数和活力指数及胚根长和胚芽鲜重;1.0mmol/L以下浓度水杨酸浸种使盐胁迫下西瓜种子萌发和幼苗生长量随水杨酸浓度提高而显著增加;2.0 mmol/L水杨酸浸种对盐胁迫下西瓜种子萌发和幼苗生长无明显影响,3.0 mmol/L水杨酸浸种进一步降低了盐胁迫下西瓜种子萌发和幼苗生长量。结果说明,较低浓度水杨酸浸种可缓解盐胁迫对西瓜种子萌发和幼苗生长的抑制作用,减轻西瓜种子萌发期盐胁迫伤害的最适水杨酸浓度为1.0 mmol/L。 相似文献
16.
本文研究了盐胁迫下不同浓度水杨酸(SA)对小麦种子萌发及幼苗生长的影响。结果表明:5 mmol/LNaCl胁迫下,小麦种子发芽率降低,根伸长、芽伸长受到抑制;小麦幼苗叶绿素含量、超氧化物歧化酶(SOD)活性降低,膜脂过氧化作用产物丙二醛(MDA)积累;0.1-1mmol/LSA处理提高了盐胁迫下小麦种子发芽率,促进小麦幼苗生长,提高小麦幼苗叶绿素含量、超氧化物歧化酶的活性,抑制MDA积累,缓解盐胁迫对小麦幼苗的伤害,并表现出浓度效应。 相似文献
17.
NaCl处理对不同品种黄瓜种子萌发的影响 总被引：1，自引：0，他引：1
采用培养皿发芽试验对NaCl处理下津优一号、津优二号黄瓜种子的相对发芽势、相对发芽率、发芽指数、活力指数及幼苗生长情况进行了研究.结果表明:NaCl处理下,两品种种子相对发芽势、相对发芽率均呈下降趋势。津优一号在NaCl≤60mmol/L时,相对发芽势、相对发芽率高于对照,津优二号在NaCl≤30mmol/L时,相对发芽率高于对照;随NaCl处理浓度的升高,两品种的发芽指数的下降率和活力指数的下降率逐渐增高、下胚轴干重均逐渐下降;NaCl处理明显抑制幼苗侧根的萌发;其中津优一号较耐NaCl处理. 相似文献
18.
Ikram-ul- Haq Asif Ali Khan Iqrar Ahmad Khan Muhammad Abubakkar Azmat 《Journal of Zhejiang University. Science. B》2012,13(7):533-544
The okra germplasm was screened for salinity tolerance at the seedling stage and during plant ontogeny. Substantial variation existed in okra for salinity tolerance at the seedling stage. An 80 mmol/L NaCl concentration was suitable for discriminating tolerant and non-tolerant okra genotypes. The pooled ranking of the genotypes, based on individual rankings for each trait (root and shoot length, germination percentage, and relative Na+ and K+) in individual NaCl concentrations, was effective for selecting tolerant genotypes. Genotypes selected at the seedling stage maintained their tolerance to NaCl during plant ontogeny, suggesting that screening of the germplasm entries and advanced breeding materials for salt tolerance at the seedling stage is effective. Among 39 okra genotypes, five were identified as the most tolerant genotypes and showed potential for use in breeding programs that focus on the development of salt-tolerant, high-yield okra cultivars. 相似文献
19.
Ya-jing Guan Jin Hu Xian-ju Wang Chen-xia Shao 《Journal of Zhejiang University. Science. B》2009,10(6):427-433
Low temperature stress during germination and early seedling growth is an important constraint of global production of maize. The effects of seed priming with 0.25%, 0.50%, and 0.75% (w/v) chitosan solutions at 15 ℃ on the growth and physiological changes were investigated using two maize (Zea mays L.) inbred lines, HuangC (chilling-tolerant) and Mo17 (chilling-sensitive). While seed priming with chitosan had no significant effect on germination percentage under low temperature stress, it enhanced germination index, reduced the mean germination time (MGT), and increased shoot height, root length, and shoot and root dry weights in both maize lines. The decline of malondialdehyde (MDA) content and relative permeability of the plasma membrane and the increase of the concentrations of soluble sugars and proline, peroxidase (POD) activity, and catalase (CAT) activity were detected both in the chilling-sensitive and chilling-tolerant maize seedlings after priming with the three concentrations of chitosan. HuangC was less sensitive to responding to different concentrations of chitosan. Priming with 0.50% chitosan for about 60～64 h seemed to have the best effects. Thus, it suggests that seed priming with chitosan may improve the speed of germination of maize seed and benefit for seedling growth under low temperature stress. 相似文献
20.
不同NaCl浓度对黄瓜种子萌发特性的影响 总被引：1，自引：0，他引：1
不同浓度的NaCl处理黄瓜种子后,通过研究其萌发过程中发芽率、胚根和下胚轴长、胚根和下胚轴以及子叶的鲜重干重、萌发的侧根数、过氧化物酶活性的变化.结果表明:低盐浓度(≤30mmol/L)对黄瓜种子萌发特性无影响或影响较小,高盐浓度(≥90mmol/L)对种子的发芽率、胚根长、下胚轴长、胚根和下胚轴的鲜重干重、子叶的鲜重、侧根数都剧烈降低,过氧化物酶(POD)活性先升后降,并与NaCl处理浓度呈负相关,但盐浓度对子叶干重的影响不明显. 相似文献