烤烟不同育苗方式的对比试验

为寻求适合贵州烟区烤烟生产实际的育苗新技术,对漂浮育苗、托盘水床育苗和常规育苗3种育苗方式进行了对比试验。结果表明:托盘水床育苗和常规育苗全天苗床温度变化相对较慢,而漂浮育苗系统升、降温迅速。托盘水床育苗的幼苗生长迅速,烟苗株高、叶数合理,茎干粗壮,叶面积较大,烟株根系发达,干物质积累量大;漂浮育苗的烟苗前期生长缓慢而后期生长迅速,成苗素质明显低于托盘水床育苗。托盘水床培育的烟苗光合速率、根系吸收面积明显占优势,根系活力与常规育苗基本一致,但明显高于漂浮育苗。因此,托盘水床育苗技术适宜于贵州烟区应用。     

烤烟漂浮育苗中不同水位炼苗对烟株生长发育及生理特性的影响

为解决烤烟漂浮育苗中的还苗期长、不耐干旱的问题,结合湿润托盘育苗技术,以常规漂浮育苗方,式为对照设置了浅水水位(垫入砖块使漂盘底面刚好与水面接触)和超低水位(垫入砖块使漂盘底面与水面隔开5 cm)等不同程度的水位炼苗试验.结果表明:烟苗生物学性状总体表现为浅水水位较好,超低水位次之,对照较差;烟苗的还苗率、根系活力、硝酸还原酶活性、光合速率和叶绿素含量总体表现为超低水位较好,浅水水位次之.     

烤烟湿润育苗技术研究

对以育苗基质和营养液配方的筛选、肥水管理方式的改进和不同育苗方式比较为主要内容的烤烟湿润育苗技术进行了探讨。结果表明,10号育苗基质配方和2号营养液配方所育烟苗综合素质最高,茎高、茎围适中,根系发达,根系活力强,根茎叶干鲜重最重;育苗肥水管理方式由传统的"一段式"改为"前期浅灌、后期浇施"的"二段式",不仅大大降低了烟农的育苗用工,而且解决了肥水单纯采用浇施,导致基质易板结、出苗率较低、生长不整齐等问题;与漂浮育苗相比,该技术不仅保持了漂浮育苗的优势,同时提高了成苗期烟苗的素质,有效地解决了返苗期偏长的问题。     

催芽型包衣种对漂浮育苗中烟苗生长的影响

试验比较了两个烤烟品种K326、云烟85的催芽型烤烟包衣种和常规包衣种对漂浮育苗中出苗时间、出苗率以及根系、叶片干鲜重、根系活力等的影响.结果表明,催芽包衣种能显著提高漂浮育苗的出苗率,特别对提高出苗的速度和整齐度,缩短出苗时间有较好的效果;催芽包衣种可以增加烟苗的株高,促进根系的生长发育;催芽包衣种的烟苗地上部和地下部干物质积累量都明显高于常规包衣种的烟苗;催芽包衣种对漂浮育苗烟苗的根系活力有明显的增加作用.     

烤烟砂培漂浮育苗的试验与应用

为了降低育苗成本,以砂作为基质研究了烤烟砂培漂浮育苗技术。结果表明:与现行漂浮育苗比较,出苗率高且出苗整齐,大约60 d可以成苗,成苗率和壮苗率较高;在出苗后至大十字期前,烟苗生长缓慢,生育期晚2~3 d;大十字期后,烟苗生长迅速,生育期与现行漂浮育苗一致;烟苗茎粗、茎高、最大叶面积、干物质积累量、总根数以及根系活力、硝酸还原酶活性、叶绿素含量的变化均表现出烟苗生长前期缓慢增长,后期急剧上升;至成苗后期,根系活力、硝酸还原酶活性、叶绿素含量又有所下降。砂培漂浮育苗的烟苗根系发达、生长健壮整体素质好,育苗成本较现行漂浮育苗降低56.58%。     

烟草托盘育苗技术改进

通过对托盘育苗技术的改进,使托盘育苗无土化,解决了托盘育苗用工量大的不足.同时也吸收了漂浮育苗的优点,克服了漂浮育苗成本高、不易管理、炼苗困难的不足,培育的烟苗根系发达,达到壮苗的标准.     

干旱胁迫对不同育苗方式烤烟生长和生理生化特性的影响

为明确干旱胁迫对不同育苗方式下烟苗移栽后的生长状况及生理生化特性的影响,通过盆栽控制土壤含水率试验,研究了干旱缺水环境下烤烟的适宜育苗方式.结果表明:干旱胁迫下,烟株脯氨酸含量和过氧化物酶活性两项指标均呈现出上升趋势.随着干旱时间的持续以及干旱程度的加深,烟株的硝酸还原酶活性则呈下降趋势.在轻度干旱条件下,漂湿育苗方式培育的烟苗移栽后生长状况好于漂浮育苗方式培育的烟苗.在极端干旱条件下,烟苗移栽14d后,两种育苗方式的烟株生长均停滞并出现叶片变黄枯萎等现象.     

增温补光对郴州烤烟漂浮育苗成苗素质的影响

湖南郴州烟区烤烟苗期常遭遇低温和寡照气候的影响。为了提高苗期烟苗质量,在该地开展了苗期增温和补光试验。结果显示,漂浮育苗苗床增温处理可以显著提高烤烟出苗率,增强成苗素质,缩短成苗时间;补光处理也可一定程度提高烟株的成苗素质,降低漂浮育苗成苗时间,但对出苗率无影响,与常规育苗差异不显著;在郴州烟区,提高漂浮育苗水温,是增强漂浮育苗成苗素质的有效措施。     

汽爆烟秆替代基质对烤烟漂浮育苗烟苗素质的影响

为研究汽爆烟秆替代商品基质对烤烟漂浮育苗烟苗素质的影响,以100%商品基质为对照,采用不同配比汽爆烟秆与商品基质混合进行烤烟漂浮育苗试验,结果表明,汽爆烟秆替代商品基质处理烟苗的出苗率在95%以上,与对照无明显差异,成苗率高于对照;成苗时烟苗茎高、叶片数及地上部分鲜干重优于对照,而茎围、根系条数、根鲜干重及叶绿素含量、根系活力、超氧化物歧化酶(SOD)活性和过氧化酶(POD)活性与对照无明显差异;汽爆烟秆替代商品基质处理基质成本比对照降低11.88～47.71元/hm²。总体而言,汽爆烟秆可以代替商品基质进行烤烟漂浮育苗。     

基质中添加育苗肥对烟苗生长及生理特性的影响

为缩短烤烟育苗周期、提高烟苗素质,在育苗基质中添加了不同用量的烟草专用育苗肥进行对比试验。结果表明:基质中添加520 g/m3育苗肥时,烟苗各生长期缩短,育苗周期较对照减少8 d。其中,从出苗到小十字期的生长时间缩短最多,为3.38 d;成苗期烟苗根系数量最多、质量最大,烟苗农艺性状指标最高,根系活力、叶片叶绿素含量(质量分数)和硝酸还原酶活性也最高。因此,在基质中加入适量(520 g/m3)育苗肥可促进烟苗生长,明显缩短烟苗生育期,同时培育出的烟苗根系发达,根系活力强。      

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

An internet compendium of analytical methods and spectroscopic information for monomers and additives used in food packaging plastics

An internet website (http://cpf.jrc.it/smt/) has been produced as a means of dissemination of methods of analysis and supporting spectroscopic information on monomers and additives used for food contact materials (principally packaging). The site which is aimed primarily at assisting food control laboratories in the European Union contains analytical information on monomers, starting substances and additives used in the manufacture of plastics materials. A searchable index is provided giving PM and CAS numbers for each of 255 substances. For each substance a data sheet gives regulatory information, chemical structures, physico-chemical information and background information on the use of the substance in particular plastics, and the food packaging applications. For monomers and starting substances (155 compounds) the infra-red and mass spectra are provided, and for additives (100 compounds); additionally proton NMR are available for about 50% of the entries. Where analytical methods have been developed for determining these substances as residual amounts in plastics or as trace amounts in food simulants these methods are also on the website. All information is provided in portable document file (PDF) format which means that high quality copies can be readily printed, using freely available Adobe Acrobat Reader software. The website will in future be maintained and up-dated by the European Commission's Joint Research Centre (JRC) as new substances are authorized for use by the European Commission (DG-ENTR formerly DGIII). Where analytical laboratories (food control or other) require reference substances these can be obtained free-ofcharge from a reference collection housed at the JRC and maintained in conjunction with this website compendium.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.     

Tests of potential functional barriers for laminated multilayer food packages. Part I: Low molecular weight permeants

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

Analysis of benzo[a]pyrene in spiked fatty foods by second derivative synchronous spectrofluorimetry after microwave-assisted treatment of samples

A simple, rapid and inexpensive method has been developed for the determination of benzo[a     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. II: Certification study

This paper describes the second part of a project undertaken to develop certified mussel reference materials for paralytic shellfish poisoning toxins. In the first part two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin and decarbamoyl-saxitoxin in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the certification exercise. Fifteen laboratories participated in this certification study and were asked to measure saxitoxin and decarbamoyl-saxitoxin in rehydrated lyophilized mussel material and in a saxitoxin-enriched mussel material. The participants were allowed to use a method of their choice but with an extraction procedure to be strictly followed. The study included extra experiments to verify the detection limits for both saxitoxin and decarbamoyl-saxitoxin. Most participants (13 of 15) were able to meet all the criteria set for the certification study. Results for saxitoxin.2HCl yielded a certified mass fraction of <0.07 mg/kg in the rehydrated lyophilized mussels. Results obtained for decarbamoyl-saxitoxin.2HCl yielded a certified mass fraction of 1.59+/-0.20 mg/kg. The results for saxitoxin.2HCl in enriched blank mussel yielded a certified mass fraction of 0.48 +/- 0.06 mg/kg. These certified reference materials for paralytic shellfish poisoning toxins in lyophilized mussel material are the first available for laboratories to test their method for accuracy and performance.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of the