LED红蓝弱光照射保持樱桃番茄冷库贮藏品质

为了探究单色光对番茄冷藏过程中品质的影响,开发樱桃番茄保鲜新技术,以绿熟期樱桃番茄(Lycopersicon esculentum Mill.)为试材,在4℃条件下分别采用发光二极管(LED,light emitting diode)红蓝单色弱光(30 lx)持续照射,研究LED红蓝单色弱光对樱桃番茄采后贮藏过程中感官和主要营养品质指标的影响。结果表明:研制的LED试验装置稳定可靠,红蓝单色光的发射光谱稳定,不因光照强度的变化而发生偏移。贮藏10 d以后LED红蓝光处理的樱桃番茄感官品质显著优于无光对照(P0.05),且LED红光处理好于蓝光处理(P0.05)。LED蓝光照射能较好地保持樱桃番茄维生素C含量(P0.05),但LED红光照射不利于维生素C含量的保持。LED红蓝单色弱光照射有利于促进樱桃番茄早期贮藏过程中的还原糖和可溶性总糖积累,显著抑制贮藏后期糖含量的下降(P0.05)。LED红蓝单色弱光照射处理还能显著延缓樱桃番茄贮藏过程中可溶性固形物下降(P0.05),提高樱桃番茄果实可滴定酸的含量,其中LED红光处理显著高于蓝光处理(P0.05)。贮藏20 d时,红光照射可显著促进番茄红素的合成,但贮藏过程中LED蓝光照射与对照差异不显著(P0.05)。综合来看,与对照(CK)相比,LED红蓝弱光(30 lx)照射有利于樱桃番茄4℃贮藏过程中感官和营养价值的保持,其中LED红色弱光照射处理效果较好。作为一种简便可行的物理保鲜方法,LED红蓝弱光持续照射处理在樱桃番茄采后营养品质调控方面具有应用潜力。     

静电场下不同处理对番茄颜色转化的影响

为了探讨静电场下不同处理因子对番茄贮藏效果的影响,以指导番茄贮藏实践,该文以“朝研219”品种番茄为试材,以果实颜色转化为评价指标,研究了在番茄高压静电场处理的贮藏过程中,不同处理因子对其贮藏效果的影响,结果表明：场强大小、电场方向、是否受电荷传递作用、所用衬垫材质的电介常数的变化,显著抑制了番茄由绿转红过程,从而延缓了果实的后熟衰老（P＜0.05）,这些因子是应用中需着重考虑的,而果实摆放量,极板金属材质的变化,对果实由绿转红的影响与对照相比,无显著差异,为次要因子;静电场处理番茄贮藏过程中,选择适宜的主要因子优化电场处理设置,才能达到延长贮藏期的目的,次要因子对其贮藏结果无显著影响,可以不加考虑。     

固封精油熏蒸对油桃采后保鲜效果的影响

为开发一种新的植物精油保鲜方法,本试验用琼脂平板固封百里香精油和薄荷精油,制成精油香膏,使精油缓慢释放,用于熏蒸油桃,并采用固相微萃取-气质联用(SPME-GCMS)分析精油香膏熏蒸时盒内空气中精油活性成分的变化,同时比较不同精油香膏熏蒸对油桃果实腐烂指数、失重率、硬度、抑菌能力以及可溶性固形物、可滴定酸、抗坏血酸和类...     

静电场处理对贮藏番茄品质及生理变化的影响

为探讨静电场对番茄贮藏品质的影响,以“朝研219”绿熟番茄为试材,从控制软化和转红出发,筛选了适宜的静电场处理条件为：场强-200 kV/m,频度2 h/d。研究静电场处理对贮藏番茄品质和生理变化的影响,结果表明：静电场处理能显著延缓番茄果实硬度的下降,抑制由绿转红的过程;可以延缓果实可溶性糖含量的下降和可滴定酸含量的上升;经负高压静电场处理的番茄,呼吸跃变推迟6 d出现,乙烯峰的出现也延迟了3 d,相对电导率与丙二醛含量较对照明显降低,说明静电场处理可调控果实细胞膜透性的变化。     

麝香草酚/聚乳酸抗菌包装对蓝莓保鲜效果的影响

为探讨以麝香草酚为抗菌剂制备的抗菌包装对蓝莓品质和生理变化的影响,本研究以灿烂蓝莓为材料,采用麝香草酚/聚乳酸抗菌包装结合低温贮藏处理,通过感官评价,检测好果率、营养品质、抗氧化酶活性等指标,并与普通聚乙烯(PE)包装进行比较,评价抗菌包装的保鲜效果。结果表明,在0℃贮藏条件下,麝香草酚/聚乳酸抗菌包装能显著延缓蓝莓果实贮藏期间的腐败,贮藏36 d仍能保持100%的好果率,而PE包装仅能保持18 d。麝香草酚/聚乳酸抗菌包装能使蓝莓保持较高的可溶性固形物含量和硬度,减少花色苷、总酚、Vc等营养物质的损失,有效抑制超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性的下降及多酚氧化酶(PPO)活性的上升,但在减少果实失水方面劣于PE包装。由此可知,麝香草酚/聚乳酸抗菌包装在蓝莓果实防腐保鲜中具有较好的应用前景,该研究结果为抗菌包装在果蔬保鲜上的应用提供了一定理论依据。     

胜红蓟精油复合微乳液体系构建及其对芦柑保鲜的影响

为更好的资源化利用入侵植物胜红蓟,提高芦柑的保鲜效果,本研究以胜红蓟精油为油相,吐温-80为表面活性剂,乙醇为助表面活性剂,碳酸钠和羧甲基壳聚糖水溶液为水相,采用拟三元相图筛选最优纳米级复合微乳液体系,并检测其在不同浓度(2.5、5.0、10.0和20.0 mg·mL^-1)下对意大利青霉、指状青霉和扩展青霉的抑菌活性和芦柑染菌抑制效果,用最优浓度处理芦柑果实,探究其对芦柑在不同贮藏条件下(25℃和4℃)的保鲜效果。结果表明,最优复合微乳液体系(A₈₀)的配方为胜红蓟精油∶乙醇∶吐温-80∶3%碳酸钠∶0.5%羧甲基壳聚糖=0.13∶0.38∶0.13∶1∶3,其粒径为34.47 nm。复合微乳液体系浓度为20 mg·mL^-1时,对意大利青霉、指状青霉和扩展青霉的抑菌效果最好,抑制率分别为64.86%、60.23%和86.96%,对芦柑的染菌抑制率为76.48%。此浓度复合微乳液A₈₀对4℃贮藏条件的芦柑保鲜效果最好,贮藏30 d后芦柑失重率为22.24%,对照组失重率为26.47%,腐烂率为11.33%,较对照组降低50%。构建的胜红蓟精油复合微乳液体系处理芦柑,不仅可以有效抑菌,延缓芦柑果实水分散失和重量损失,而且能延长芦柑的保鲜期。本研究结果为胜红蓟精油天然保鲜剂的开发和芦柑储藏保鲜提供了一定的理论基础。     

3种植物精油熏蒸处理对油桃保鲜效果的影响

为探明香榧假种皮精油、枇杷叶精油和佛手精油熏蒸处理对采后油桃的保鲜效果,以中油四号油桃为试材,采用密闭容器熏蒸法研究3种植物精油对油桃采后主要致病菌的抑制作用及对其感官品质、生理生化的影响。结果表明,香榧假种皮精油可有效抑制灰霉病菌、根霉病菌菌丝的生长,其EC50值均低于枇杷叶精油和佛手精油处理,分别为81.672μL·L~(-1)和209.131μL·L~(-1)。在200μL·L~(-1)浓度下,与枇杷叶精油和佛手精油处理相比,香榧假种皮精油熏蒸处理可有效降低油桃采后的腐烂,于25℃贮藏10 d后腐烂指数较对照降低了63.73%,并且仍能较好地维持失重率和硬度,诱导果实中过氧化物酶(POD)、多酚氧化酶(PPO)、超氧化物歧化酶(SOD)及过氧化氢酶(CAT)活性的升高,抑制丙二醛(MDA)含量的积累,对果实可溶性固形物(SSC)、可滴定酸(TA)和抗坏血酸(Vc)含量等指标均无明显影响。综上所述,香榧假种皮精油熏蒸处理能够抑制采后油桃品质的下降,延缓后熟衰老和腐烂发生,具有进一步开发成果蔬保鲜剂的潜力。     

间歇热处理时间对樱桃温度场及贮藏品质的影响

间歇热处理过程中,温度的变化会激发果实内部生理变化,研究不同处理时间下果实组织温度分布及变化速率对揭示热处理保鲜机理具有重要意义。该研究以樱桃为处理对象,采用50℃热水,20℃冷水交替喷淋的处理方式,同时选择20、100、180 s作为不同的间歇处理时间,果实的贮藏品质作为评价指标。建立单个果实的非稳态传热模型,对间歇热处理时樱桃组织的传热规律及动态响应过程进行数值分析。结果表明,间歇喷淋热处理可以提高樱桃贮藏品质,且不同的热处理时间对果实的温度场及品质的影响有显著差异（P<0.05）。优化后的参数为：间歇处理时间180s,50℃喷淋处理3次,总热处理时间为540 s。在此条件下樱桃与处理介质之间的热量传递最充分,单个果实半径1/2处温度平均值为27.71℃,中心温度平均值为30.85℃。优化间歇热处理组的腐烂率比未做任何处理的对照组低53.4%,能较好维持果实硬度。根据传热模型及相关结论,建议间歇处理时间应大于温度变化速率峰值的出现时间。研究结果可为樱桃采后保鲜技术提供理论参考。     

樱桃贮藏保鲜技术研究进展

樱桃果实色泽艳丽、营养丰富、皮薄多汁,深受消费者喜爱。由于樱桃果皮薄、含水量高,以及成熟期集中,采摘期高温多雨,采后极易腐烂变质。因此,采后贮藏保鲜是樱桃产业发展中的重要环节。分析影响樱桃贮藏效果的因素主要有采后生理变化、采摘成熟度、病害等,综述温度控制、气调保鲜、减压贮藏、辐射处理、保鲜剂处理、涂膜技术、保鲜包装等樱桃保鲜技术研究进展。     

1-MCP负压渗透处理对鲜枣常温贮藏品质的影响

为了深入了解1－甲基环丙烯（1-MCP）对鲜枣的保鲜效果,以山东大瓜枣（Ziziphus jujube Mill cv. Dagua）为试材,研究了1-MCP负压渗透处理对鲜枣贮藏期间品质的影响。试验结果表明：经1 μL/L 1-MCP负压渗透处理果实24 h即可显著延缓枣果实贮藏期间硬度的下降,延长果实的贮藏期。与对照相比,1-MCP负压渗透处理可以有效地抑制枣果实贮藏期间的呼吸强度、延缓果皮叶绿素含量下降;延缓鲜枣果实可溶性糖及可溶性果胶含量上升,保持了可滴定酸含量的稳定性和较高的还原糖含量,有效延缓     

低氮和干旱胁迫对富士和秦冠生长及氮素利用的影响

【目的】以富士（Fuji）、 秦冠（Qinguan）嫁接在平邑甜茶（Malus hupehensis Rehd.）上的当年生盆栽苗为试验材料,采用砂培方法,研究了缺氮胁迫和干旱对富士和秦冠生长情况、 光合参数、 植株各部位氮磷钾含量及氮素利用效率的影响,分析比较了低氮干旱条件下富士和秦冠生长及氮素利用的差异,以期为果树生产高效肥水利用提供理论指导。【方法】试验共设四个处理: 正常氮正常水（ZZ）、 低氮正常水（DZ）、 正常氮干旱（ZG）、 低氮干旱（DG）。氮素和水分均设置两个水平,分别为正常氮（6 mmol/L NO-3-N）、 低氮（0.3 mmol/LNO-3-N）、 正常供水（保持盆中砂子相对含水量为饱和含水量的80%~85%）、 干旱处理（保持盆中砂子相对含水量为饱和含水量的60%~65%）。【结果】富士和秦冠的生物量（茎和叶）、 株高茎粗等生长指标以及光合速率、 气孔导度、 蒸腾速率均为正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）,并且相对应处理下秦冠的以上指标均高于富士;正常供水下,缺氮处理使富士、 秦冠的根冠比比正常氮处理均有所增加,富士提高了2.05%,秦冠提高了22.40%。富士和秦冠的氮、 磷、 钾含量均表现出正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）; 氮、 钾元素含量在植株各部位的分布顺序依次是叶＞根＞茎,磷元素则是根＞叶＞茎;光合氮素利用效率（PNUE）和氮素利用效率表现为秦冠处理之间差异极显著,富士处理之间差异不显著;秦冠的PNUE和NUE明显高于富士,在低氮正常水（DZ）处理下,秦冠氮肥利用率比富士高42.07%,在低氮干旱（DG）处理下高64.14%;低氮胁迫下富士和秦冠的NUE显著提高,并且秦冠提高的幅度高于富士。【结论】施用氮肥能够显著提高富士与秦冠的干物质量,同等水肥条件下,秦冠生长优于富士;水分亏缺会减少叶片对氮的吸收,干旱条件下适度增施氮肥,可提高果树的抗旱能力;低氮干旱胁迫下秦冠的生长指标、 光合指标及氮素利用效率指标均优于富士,表现出较强的抗低氮干旱胁迫的能力。     

Pasture Vegetation Elemental Analysis by Laser-Induced Breakdown Spectroscopy

Laser-induced breakdown spectroscopy (LIBS) is a new technique for the analysis of plant material. This study investigates the application of LIBS to pasture-based plant samples. The LIBS measurements were obtained from pelletized pasture samples (100 samples) that had been also analyzed by inductively coupled plasma–optical emission spectroscopy (ICP-OES) following microwave digestion for calibration and comparison purposes. Comparisons for elements sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), boron (B), phosphorus (P), and sulfur (S) showed that LIBS could be used for almost all the standard profile total elements with concentrations down to low mg/kg levels (observed error of Na: 0.024 percent, K: 0.18 percent, Mg: 0.016 percent, Ca: 0.073 percent, P: 0.017 percent, Mn: 31 mg/kg, Fe: 150 mg/kg, Zn: 6.6 mg/kg, and B: 1.1 mg/kg). Elemental analysis at less than mg/kg levels was not possible using LIBS. The elements S and Cu were particularly difficult to analyze with reliability using LIBS at the concentration levels found in the plant samples. Replacing microwave digestion and subsequent ICP analysis with a direct analysis of dried plant samples using LIBS has the potential to improve the productivity and reduce the cost of testing.     

Faculty positions:Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Biodiversity and ecogeography of wild Lactuca spp. in some European countries

Staff members of the Department of Botany of Palacký University in Olomouc and Gene Bank Department – Workplace Olomouc, Research Institute of Crop Production in Prague, Czech Republic, conducted an expedition in seven European countries (Austria, Czech Republic, France, Germany, Italy, the Netherlands, Switzerland) in August/September 1999 to collect wild Lactuca spp. germplasm and study its geographic distribution, ecology and biodiversity. During the mission, more than 600 locations were visited resulting in the collection of 602 seed samples (accessions) of wild Lactuca species and 13 seed samples of related genera (Chondrilla and Mycelis). Lactuca serriola f. serriola, L. serriola f. integrifolia, L. saligna and L. viminea subsp. chondrilliflora were prevalent in southern Europe (Italy, France), however, only L. serriola was common in central and western Europe (Austria, Czech Republic, Germany, Netherlands, Switzerland). The greatest diversity of Lactuca species was found in France, where also the most seed samples (165) were collected. The most characteristic habitats with a high density of Lactuca spp. populations were observed along roads and highways, grassy ditches, ruderal communities, and dust-heaps. Natural infections by powdery mildew (Erysiphe cichoracearum) and downy mildew (Bremia lactucae) on some wild Lactuca spp. were observed. Recent observations concerning the geographic distribution, population structure, habitats, and natural occurrence of diseases of Lactuca spp. are discussed. This assemblage of genetic resources of Lactuca spp. can serve as the basis of future studies of species diversification, spatial population structure, plant microevolution, domestication processes, and genetic variability of host-parasite interactions.     

Macroinvertebrates in North American tallgrass prairie soils: effects of fire, mowing, and fertilization on density and biomass

The responses of tallgrass prairie plant communities and ecosystem processes to fire and grazing are well characterized. However, responses of invertebrate consumer groups, and particularly soil-dwelling organisms, to these disturbances are not well known. At Konza Prairie Biological Station, we sampled soil macroinvertebrates in 1994 and 1999 as part of a long-term experiment designed to examine the effects and interactions of annual fire, mowing, and fertilization (N and P) on prairie soil communities and processes. For nearly all taxa, in both years, responses were characterized by significant treatment interactions, but some general patterns were evident. Introduced European earthworms (Aporrectodea spp. and Octolasion spp.) were most abundant in plots where fire was excluded, and the proportion of the total earthworm community consisting of introduced earthworms was greater in unburned, unmowed, and fertilized plots. Nymphs of two Cicada genera were collected (Cicadetta spp. and Tibicen spp.). Cicadetta nymphs were more abundant in burned plots, but mowing reduced their abundance. Tibicen nymphs were collected almost exclusively from unburned plots. Treatment effects on herbivorous beetle larvae (Scarabaeidae, Elateridae, and Curculionidae) were variable, but nutrient additions (N or P) usually resulted in greater densities, whereas mowing usually resulted in lower densities. Our results suggest that departures from historical disturbance regimes (i.e. frequent fire and grazing) may render soils more susceptible to increased numbers of European earthworms, and that interactions between fire, aboveground biomass removal, and vegetation responses affect the structure and composition of invertebrate communities in tallgrass prairie soils.     

Properties of anaerobically digested and composted municipal solid waste assessed by linking soil mesofauna dynamics and nitrogen modelling

We have studied the effect of anaerobically digested (ADMSW) and composted municipal solid waste (CMSW) on mineralization and foodweb dynamics to verify the hypothesis that ADMSW would immobilize N right after addition to soil in contrast to addition with CMSW. Another hypothesis was that the mesofauna (enchytraeids and microarthropods) would stimulate N release from the decomposer community. We measured excretion of -N and urea-N from the mesofauna and hypothesized that enchytraeids would release urea. ADMSW and CMSW were amended to pots with sandy loam and barley. The pots were divided into treatments with or without mesofauna. Mesofauna, plant N and biomass, soil N and ergosterol (fungal biomass) were measured over a 113-day period of four equidistant samplings. Soil respiration, N mineralization and N release by the mesofauna were modelled from concurrent studies. ADMSW- and CMSW-treated soils initially (<20 days) immobilized N. The amendments did not increase plant growth substantially, and this was probably due to N-limitation in the early stages of plant growth. Enchytraeid abundance was about three times higher in ADMSW- than CMSW-treated soils, indicating that ADMSW contained more labile compounds, bacteria, and microfauna. The mesofauna did not affect N-content, but the cumulated -N excreted by the mesofauna was estimated to be substantial and about one-fifth of total plant N in ADMSW. An explanation for this discrepancy might be that in the absence of the mesofauna, other members of the detrivore and microbivore community performed the mesofauna’s function. Neither enchytraeids nor microarthropods excreted urea.     

Faculty positions: Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Faculty positions: Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Variation in quality parameters between and within 14 Nordic tree fruit and berry species

Abstract

A 3-year study was carried out to investigate quality parameters in 14 tree fruit and berry species grown in southern Norway. The species were blueberry, apple, aronia, sour cherry, sweet cherry, red raspberry, strawberry, blackcurrant, gooseberry, red currant and elderberry, harvested along with wild bilberry, cloudberry and lingonberry. Significant differences between species were identified for all quality parameters. The coefficient of variation between species was lowest for pH (12.5%), dry matter (18.9%) and soluble solids (25.3%), followed by titratable acids (59.3%), total phenolics (83.8%), antioxidant capacity FRAP (85.7%) and antiradical power by the DPPH-assay (97.8%), total monomeric anthocyanins (132%) and ascorbic acid (137%). Average coefficient of variation within species were lower and ranged from 4 (pH) to 62% (ascorbic acid). Only the FRAP values were significantly affected by harvesting year with lower levels in 2004 than in 2005 and 2006. There were significant interactions between species and harvesting year for dry matter, soluble solids, pH, ascorbic acid and FRAP. The results indicate generic ranges in composition within species independent upon growing location and climate, and the composition of the tree fruits and berries is not likely to deviate from these ranges. It is concluded that desirable composition of tree fruits and berries and their products should primarily be achieved by selection among species rather than searching fors broadened variation within individual species.     

Potassium Fixation and Release Characteristics in Rhizosphere and Nonrhizosphere Soils for a Rapeseed–Rice Cropping Sequence

Potassium (K) fixation and release in soil are important factors in the long-term sustainability of a cropping system. Changes in K concentration and characteristics of K fixation and release in rhizosphere and nonrhizosphere soils in the rapeseed (Brassica napus L.)–rice (Oryza sativa L.) rotation were investigated using a rhizobox system. The concentrations of different forms of K in both rhizosphere and nonrhizosphere soils decreased with plants compared to without plants, regardless of K fertilizer application. Potassium uptake by crops mainly came from the rhizosphere soil. In the treatment without K fertilizer (–K), the main form of K supplied by the soil to the crops was 1.0 mol L^?1 nitric acid (HNO₃) nonextractable K, followed by nonexchangeable K, and then exchangeable K. In the treatment with K fertilizer (+K), the main K forms supplied by the soil to the crops were exchangeable K and nonexchangeable K. The amount and rate of K fixation after one cycle of the rapeseed–rice rotation was greater in rhizosphere soil than in nonrhizosphere soil. The amount and rate of K fixation of soil in the +K treatment were significantly less than in the –K treatment. The cumulative amounts of K released with 1.0 mol L^?1 ammonium acetate (NH₄OAc) and 1.0 mol L^?1 HNO₃ extraction increased with the increasing numbers of extractions, but the K-releasing power of soil by successive extraction decreased gradually and finally became almost constant. The release of K was less in rhizosphere soil than in nonrhizosphere soil. The release of K in the +K treatment was similar to that in the –K treatment in rhizosphere soil, but the K release in nonrhizosphere soil was greater with the +K than the –K treatment. Overall, the information obtained in this study will be helpful in formulating more precise K fertilizer recommendations for certain soils.