荔枝采后果皮变色分子机理研究

以不同处理荔枝在贮藏过程中冻干果皮为研究对象,采用高效液相色谱分析鉴定,通过对荔枝贮藏过程中果皮中有机物分子含量变化的研究,得出果皮中一种称为类黄酮的酚类物质即水溶性花色素苷含量的变化是引起荔枝果皮变色的一个重要原因,而果皮中的其他有机物如黄烷醇类物质和黄酮醇类物质对水容性花色素苷含量的变化有着重要的影响。不同保鲜处理的荔枝贮藏结果表明:冰水处理的荔枝果皮比热水处理的荔枝果皮中的花色素苷降解速度慢,本实验可以为研究荔枝采后褐变机理、果皮着色变化与酚类物质的关系提供理论指导及相应的操作工艺。     

食品添加剂对荔枝采后病原菌的抑菌活性及其保鲜效果

研究18种食品添加剂对荔枝采后病原菌的抑菌活性及保鲜效果,结果表明:在100μg/mL浓度下,邻苯基苯酚钠、叔丁基对苯二酚、脱氢醋酸钠、3-叔-4-羟基苯甲醚、联苯对3种病原菌的平均抑菌活性大于70%,其它13种食品添加剂的平均抑菌活性小于50%。在常温下,维生素E、甘草抗氧化剂对荔枝具有较好的保鲜效果,防效大于38%,邻苯基苯酚钠、异抗坏血酸钙、叔丁基对苯二酚有促进荔枝果皮褐变的作用,其他13种食品添加剂对荔枝的防腐保鲜效果介于0～30%之间。在低温贮藏条件下,维生素E、甘草抗氧化剂处理的荔枝花色苷降解较对照缓慢,能显著抑制PPO、POD酶活性,延缓SOD酶活性下降,从而延缓荔枝果实的衰老。     

国内外荔枝采后生理贮藏保鲜研究的进展

综述了国内外在荔枝采后生理、病理及贮藏保鲜研究的最新进展,并对今后荔枝保鲜研究的发展方向提出建议。     

荔枝果实复合保鲜剂的筛选及其常温保鲜效果的研究

为了筛选出有利于荔枝贮藏的复合保鲜剂,以‘井岗红糯’荔枝果实为试验材料,通过正交试验研究了不同浓度的油菜素内酯（brassinolide, BL）和曲酸（kojic acid, KA）配比对采后荔枝果实的保鲜效果。结果表明,在25 ℃贮藏条件下,对荔枝果实的最佳保鲜配方为：油菜素内酯40 μmol/L、曲酸35 mmol/L,浸泡时间为3 min,该复合保鲜剂配方能较好地抑制荔枝果实褐变和腐烂,降低果皮相对电导率、果皮pH和果皮丙二醛（malonaldehyde, MDA）含量,延缓果肉总可溶性固形物（total soluble solids, TSS）和维生素C（vitamin C, VC）含量的下降,维持较高的果皮色度L ^*值、a ^*值、C ^*值和花色苷含量,抑制了多酚氧化酶（polyphenol oxidase, PPO）、过氧化物酶（peroxidase, POD）及漆酶（laccase, Lac）的活性。     

不同荔枝品种采后果皮褐变与多酚氧化酶关系的研究

以无核荔枝、妃子笑、紫娘喜3个荔枝品种为试材,研究了不同耐贮性荔枝品种果实采后果皮多酚氧化酶活性与果皮褐变之间的关系,结果表明,在相同贮藏阶段,3个荔枝品种中无核荔枝褐变指数最高,妃子笑次之,紫娘喜最低。不同处理条件下妃子笑、紫娘喜果皮PPO酶活性均呈先上升后下降的趋势,常温贮藏时无核荔枝果皮PPO活性逐渐下降,低温贮藏则先下降后上升再下降。果实贮藏前期,PPO结合酶、游离酶与总酶活性以无核荔枝最高,妃子笑次之,紫娘喜最低。新采收果实中,紫娘喜果皮PPO同工酶仅2条带,妃子笑3条,而无核荔枝有4条。不同处理对同工酶带数无影响,但低温减少了无核荔枝某些阶段果皮PPO同工酶带数。不同品种荔枝果皮褐变进程差异与果实贮藏前期果皮PPO酶活性差异及同工酶带数有关。     

荔枝果实干制加工的热烫和无硫护色工艺

荔枝是我国南方一种重要的热带、亚热带水果,具有较高的营养价值和商业潜力.然而,在高温高湿季节,采后荔枝果实极易发生腐烂变质、果皮褐变、病原菌侵染等品质劣变现象.因此,荔枝果实除鲜食外,常被加工成不同的商业产品,特别是荔枝果干.干制荔枝由于干制加工时间较长,易发生果皮褐变,导致其外观色泽、产品质量和风味丧失,最终限制荔枝...     

荔枝果皮褐变过程中膜脂过氧化及相关酶活性变化的比较研究

以紫娘喜、无核荔枝、小丁香等3个海南主栽荔枝品种为试材,研究了室温贮藏过程中果皮褐变与膜脂过氧化及有关酶活性变化的关系,结果表明,随着贮藏时间延长,3个品种果皮都表现出褐变指数上升,丙二醛(MDA)含量升高,质膜透性增大,抗坏血酸氧化酶(APX)活性下降,脂氧合酶(LOX)、过氧化氢酶(CAT)、谷胱甘肽还原酶(GR)活性先升后降。但紫娘喜褐变最慢,无核荔枝褐变最快。耐贮的紫娘喜MDA含量、质膜透性及LOX活性较不耐贮的无核荔枝要低,GR活性较不耐贮藏的无核荔枝高。除GR活性外,无核荔枝其余指标变化幅度大于紫娘喜。不同品种果皮褐变进程差异与LOX活性变化、活性氧清除途径及质膜破坏进程差异有关。     

荔枝褐变损失估计研究

荔枝褐变损失估计是荔枝褐变控制的重要环节,以兰竹荔枝为材料,研究由于果皮褐变导致荔枝的损失;在调查兰竹荔枝褐变情况的基础上,分析果皮褐变对荔枝感官品质和销售价格的影响.结果表明:当褐变等级达到Ⅲ级时会对荔枝的感官品质和销售价格产生显著影响.按照不同褐变等级与损失率之间的关系,采用回归分析,建立的兰竹荔枝果肉风味、可溶性固形物和经济的损失率最佳估测模型分别为:逻辑斯蒂模型FALR=62.279 8/[1+EXP(5.086 8-1.241 0X)]、逻辑斯蒂模型TSSLR=37.120 6/[1+EXP(5.474 0-1.689 7X)]和线性模型ELR=-24.671 0+19.347 0X.采用上述模型对福建省兰竹荔枝常温下贮藏的逐日经济损失进行了量化估计,结果发现,随贮藏时间的延长兰竹荔枝的经济损失逐日加重.本研究为荔枝褐变的控制提供了理论依据.     

几种处理对采后荔枝果皮水分变化与褐变的影响

研究不同处理对采后荔枝果皮水分变化及果皮褐变的影响。结果表明：HgCl2能够抑制果皮圆片失水,以0.2 mmol/L作用最显著。50 μmol/L Forskolin对果皮失水起促进作用,其它处理无显著影响。0.2 mmol/L HgCl2和果实套袋都能抑制果实失重,减缓果皮含水量下降,且能延缓果皮褐变进程。讨论HgCl2抑制果皮失水的机理。     

采前香菇多糖处理对妃子笑荔枝果实采后生理及抗病性的影响

研究荔枝果实采前喷施0.5 mg/mL香菇多糖对采后常温贮藏过程中的生理效应及抗病性的影响。结果表明：采收前香菇多糖处理有效地降低了果实的呼吸强度和细胞的膜脂过氧化程度，并延缓了花色苷降解，抑制了荔枝果实果皮的褐变进程；轻微抑制了过氧化物酶(POD)和多酚氧化酶(PPO)活性的变化。此外，采前喷施香菇多糖还提高了果皮中的β-1，3-葡聚糖酶(GLU)和苯丙氨酸解氨酶(PAL)的活性。由此表明，采前喷施香菇多糖可维持细胞膜的完整性而延缓荔枝果实的衰老，并通过诱导荔枝果实的抗性来减少采后病害的发生。     

Preparation and characterization of fibers of waste and fresh polyethylene terephtalate and mixtures of them

Textile fibers were obtained from secondary polyethylene terephtalate (PET) and its mixtures with primary PET at initial orientation of 18000–33000 %, rate of additional orientation drawing 3.5–6.5 times and temperature of thermal fixation 363–413 K. The fibers’ tensile strength was found to decrease and elongation at break to increase with the decrease of their linear density under the conditions of fibers formation. For the fibers based on polymer mixtures, the presence of oxidized fragments in the secondary PET limited the compatibility of the two polymers which resulted in deteriorated tensile properties. The linear density (4–16 dtex), tensile strength (30–50 cN/tex) and elongation at break (20–60 %) of the PET fibers obtained were close to these for the industrially produced polymer fibers. The values of the average diameter of the fibers formed and oriented under laboratory conditions allows classifying them between the fine and the coarse textile fibers which makes them suitable for the textile industry.     

我国麻类标准现状与分析

介绍了我国麻类标准的现状。通过分析,指出了存在的问题,主要表现在标准体系不完善、标准更新不及时,协调性差及贯彻执行不力等。提出了我国麻类标准应采取的对策。     

Characteristics of photosynthesis and conductance of potato canopies and the effects of cultivars and transient drought

Gas-exchange characteristics of potato (Solanum tuberosum L.) canopies were determined with crop enclosures under condition of optimal water supply, during soil water depletion, and during recovery from drought-stress. The plants were grown under a rainshelter in large containers with 2-m² surface area. Control plants received water throughout the growth period. In Expt. 1, transient drought was imposed by interrupting water supply completely for 22 days. During the 33-day period of drought treatment in Expt. 2, the stressed plants received half the amount of water that was given to the control plants (irrigations 2–3 times per week).

During soil water depletion, stomatal conductance of the canopy was reduced earlier and more than photosynthesis. This resulted in a lower internal carbon dioxide concentration in the leaves of stressed plants and a higher ratio between photosynthesis and stomatal conductance. The value of that ratio increased as soil water potential dropped.

Water-use efficiency ( ) increased during drought stress. The cultivar Bintje showed a larger ratio between photosynthesis and stomatal conductance of the canopy and a higher than cv. Saturna, both for optimal water supply and during drought stress.

Photosynthesis and conductance of the canopy started to recover immediately upon rewatering, even when relative values had declined to 20–30% during the preceding stress period. After release from stress, the leaves in the top layer of the canopy had a higher stomatal conductance in treated plants than in control plants.     

棉花病虫全程绿色防控技术应用与推广

经过多年实践,探索总结出抗病虫品种、频振式太阳能杀虫灯、糖盆诱蛾、黄蓝板诱虫、生物多样性控虫等绿色防控技术,形成了切合库尔勒实际的棉花病虫全程绿色防控技术模式。介绍了上述技术措施及其在当地棉田的推广应用效果。     

热区蔬菜质量安全分析与评价

对影响我国热区主要蔬菜产前、产中、产后的质量安全相关因素与现状进行调研,获取基础数据与有关信息。对比分析国内不同生产区质量安全存在的差异与差距,研究我国热区蔬菜从生产至市场各个环节的质量安全评价方法,提出建立我国热区蔬菜质量安全评价体系方案。     

水稻病虫害绿色防控与统防统治融合技术模式示范

2017—2018年,在同安镇粮食产能区示范推广水稻病虫害绿色防控与统防统治融合技术模式,取得了显著成效。融合技术示范区比常规区减少用药2~3次,用药量减少37.6%,防治成本降低400元/hm^2;水稻产量增加12.8%,收益增加2 835元/hm^2。     

Effects of Organic and Chemical Fertilizers and Arbuscular Mycorrhizal Inoculation on Growth and Quality of Cucumber and Lettuce

Summary

Arbuscular mycorrhizae were inoculated into phosphorus-deficient soil fertilized with either organic or chemical fertilizer with cucumber (Cucumis sativus L.) as the first crop and lettuce (Lactu-ca sativa L.) as the second crop but without additional fertilization and AM inoculation. AM increased dry matter and fruit yield of cucumber significantly in the unfertilized, organic-fertilized and P-deficient plants compared with the fully chemical-fertilized plants. AM inoculation increased the available phosphorus in plant and soil by around 30% for all treatments except for those chemically-fertilized. The rate of AM infection did not differ significantly among the fertilization treatments, but the infection intensity was higher in unfertilized, organic-fertilized and phosphorus-deficient treatments than chemical-fertilized treatment. The residual effects of AM-inoculated to cucumber were evident for lettuce in all pre-treatments that were unfertilized and un-inoculated for the second cropping. Without P-fertilization, neither crop could grow optimally even when the soil was inoculated with AM, suggesting that AM could not serve as a substitute for phosphorus fertilizer. However, the other beneficial effects of AM on crop growth and yield could not be fulfilled with phosphorus fertilizer.     

云南省"双高"甘蔗生产与发展

从自然生产条件、龙头企业状况和产业经济效益3方面论述了云南省“双高”甘蔗发展的优势条件.分析了现阶段“双高”甘蔗发展中存在的主要问题,即甘蔗产业科技落后、蔗园建设投入不足、加工企业规模较小,产品单一.从“双高”甘蔗优势产业带建设,甘蔗种子工程体系,“双高”甘蔗科技、甘蔗产业化经营发展与科技培训等方面提出了“双高”甘蔗发展的建议和措施.     

生物质能作物——甘薯开发利用现状及趋势

甘薯是世界上重要的粮食、饲料、工业原料及新型能源用块根作物，在我国乃至世界再生能源开发中起到重大作用，其分布地域广，适应性强，沙荒地、岗坡地均可种植。生物产量高，而且种植栽培容易。甘薯含淀粉15％～30％，晒干率20％～35％，世界各国以薯干或淀粉为原料生产乙醇有着悠久的历史。随着全球能源的日趋紧张，乙醇作为一种可再生的环保燃料．将快速步入全球成品油市场，在替代汽油供应方面起到越来越大的作用。各国正在推行或制定燃料乙醇计划，并着眼于生物燃料乙醇应用方案，认为甘薯可能是摆脱将来粮食和能源危机的“最后一张王牌”。     

春季氮肥和多效唑调控对小麦生育和产量的影响

为明确春季调控措施对冬小麦生长发育和籽粒产量的影响,以冬小麦品种石新828为材料进行田间试验,4个处理分别为:起身期追全部氮肥(除基肥外,下同)并叶面喷多效唑(N1);起身期追2/3氮肥并喷多效唑+拔节期追1/3氮肥(N2);起身期追1/3氮肥+拔节期追2/3氮肥(N3);拔节期追全部氮肥(N4)。生育期间测定群体和个体生育特性,成熟期调查产量性状。结果表明,N1和N2处理小麦拔节期的总茎数、叶面积指数(LAI)和干物质积累量均显著高于N4和N3处理。孕穗期N4和N3处理小麦的总茎数、LAI和干物质积累量显著高于N1和N2处理。开花到成熟期各处理的总茎数、LAI和干物质积累量差异均不显著。孕穗期前,不同处理的株高差异不显著,孕穗期后,N4处理的株高最高,且显著高于N1处理。各处理基部节间直径和中上部节间长的差异不显著,N4处理基部第一节间长度显著大于其他处理。随追氮时期前移或前期施氮量增多,不孕小穗数减少,结实小穗和穗粒数增加,N1比N4处理不孕小穗数显著减少,结实小穗和穗粒数显著增多。N1处理小麦成熟期的千粒重最高,且显著高于N4处理。N1处理的籽粒产量最高,且显著高于N3和N4处理。起身期追氮配合多效唑调控,可以获得比拔节期追氮更高的穗粒数和千粒重,从而获得更高的产量。