生防酵母菌结合钼酸铵对冬枣采后主要病害防治的研究

研究美极梅奇酵母菌(Metschnikowia pulcherrima)与不同浓度(5、10、15、20 mmol/L)的钼酸铵结合使用对冬枣果实采后黑腐病和青腐病的防治效果以及钼酸铵对美极梅奇酵母菌生长的影响。结果表明,不同浓度的钼酸铵对美极梅奇酵母菌的生防效果影响不同,其中美极梅奇酵母菌与较低浓度(5 mmol/L)的钼酸铵溶液结合使用时对冬枣果实黑腐病和青腐病的防治效果最佳,美极梅奇酵母菌在含有5 mmol钼酸铵的NYDB液体和固体培养基以及冬枣伤口上的生长都未受到明显的抑制。因此,美极梅奇酵母菌与钼酸铵结合使用在控制冬枣采后贮藏中的病害方面具有潜在的应用价值。     

拮抗酵母菌结合热水浸泡处理对冬枣采后腐烂及品质的影响

采用拮抗酵母菌（美极梅奇酵母菌（Metschnikowia pulcherrima））单独处理或结合热水浸泡处理（55 ℃,30 s）冬枣果实, 研究在模拟货架条件下（24 ℃）贮藏7 d,不同处理对人工接种橘青霉或链格孢菌后冬枣伤口的腐烂率、病斑直径和对冬枣自然腐烂及贮藏品质的影响。结果表明,采用拮抗酵母菌单独处理及结合热水浸泡处理都可显著降低人工接种致病菌冬枣的腐烂率、病斑直径及减轻冬枣的自然腐烂程度,并能提高冬枣的贮藏品质,其中以美极梅奇酵母菌结合热水浸泡处理的效果最佳,是一种可替代化学杀菌剂控制冬枣果实采后腐烂的较理想的处理方法。     

鲜枣采后生防菌株梅奇酵母XY201培养条件的优化

梅奇酵母（Metschnikowia zizyphicola）XY201是从冬枣表面分离筛选的新酵母菌种,对采后冬枣病原菌具有很好的抑制作用。本试验研究了该酵母菌对碳源、氮源和无机盐的利用情况,以及温度、初始pH和接种浓度三个因素对梅奇酵母生物量的影响,优化其培养基配方和培养条件。结果表明,梅奇酵母最大生物量的培养基配方为：2%蔗糖＋2%牛肉蛋白胨＋0.05%磷酸二氢钾＋0.05%硝酸钠;最优培养条件为：培养温度25℃,初始pH 6.0,接种浓度1%;在上述培养条件下进行摇瓶培养,梅奇酵母的最佳培养时间为接种后72 h。     

生防酵母菌培养条件研究

以吸光度为指标,研究美极梅奇酵母菌生长的曲线及碳源、氮源、装液量、接种量、pH值及温度等对其生长的影响。美极梅奇酵母菌在YPD培养基中的生长曲线是0~10 h为延滞期,10~22 h为对数期,22~30 h为稳定期,30 h后为衰亡期;美极梅奇酵母生长的最佳碳源是葡萄糖,最合适发酵氮源是尿素,最佳装液量为100 mL/250 mL,最佳接种量为2%,最佳初始pH值为5.0,最适温度为30℃。     

Forging Process Development of Thrust Cone Based on Simulation Technology

以藁城、黄骅、沾化冬枣为试材,研究了不同产地冬枣采后贮藏过程中的品质变化.试验结果表明,藁城、黄骅、沾化冬枣的冰点分别为-3.5℃、-4.2℃、-3.9℃;在0℃贮藏条件下,随着贮藏时间的延长,不同产地冬枣硬度均随着贮藏期的延长而下降,VC含量逐渐减少,可滴定酸含量在贮藏过程中整体上呈下降趋势,沾化冬枣酸含量最高,藁城冬枣还原糖含量最小,在贮藏过程中变化较大.贮藏结束后各地冬枣硬度差异极显著(P＜0.01),VC含量差异显著(0.01＜P＜0.05),可滴定酸含量差异极显著(P＜0.01),还原糖含量差异极显著(P＜0.01);黄骅地区土壤中平衡的氮、磷、钾配比,适宜的气候条件,导致黄骅冬枣耐贮性优于藁城、沾化冬枣.     

冬枣减压贮藏保鲜及采后生理变化

冬枣减压贮藏对其采后延缓衰老和抑制酒化起着重要作用;为冬枣采后生理变化的研究和贮藏保鲜提供理论依据.     

冬枣气调贮藏保鲜技术

冬枣原产中国,主要栽培区域集中在山东、河南、河北等省份,近几年来仅山东省就发展到1.8万hm2左右,产量达40余万t,但面临着一系列采后贮藏保鲜难题。冬枣在常温下保存期仅为6～7天,超期后则变成泡浆果,引起水分丧失,皱皮、果肉变软,风味下降,果实很快霉烂。有些研究认为,冬枣为呼吸跃变型果实,而有些则认为无明显的呼吸高峰。冬枣气调贮藏是一项技术性很强,操作严格的过程,从采前处理、采收质量、采后处理、贮藏的温湿度以及气体成分的控制,都要精确、细心地管理和操作,以保证贮藏的最佳效果。笔者以冰轮公司生产的可移式气调冷藏集装箱为贮…     

冬枣贮藏保鲜技术研究进展

从冬枣贮藏保鲜的方法和影响其贮藏保鲜的因素等方面,对冬枣贮藏保鲜技术研究现状进行了较为详细的论述。总体来看,冬枣贮藏保鲜的物理贮藏方法包括低温贮藏、气调贮藏和减压贮藏,化学方法中包括一些化学杀菌剂、保鲜剂和激素处理,考虑到化学药剂的残留对人体的影响,近几年来,科研人员逐步探索开发冬枣采后生物防治领域,并取得了一定的成绩;同时,也论述了影响冬枣保鲜效果的主要因素有冬枣自身因素、农业技术措施和环境条件等,并对当前研究工作存在的问题及今后的研究重点进行了讨论。     

冬枣贮藏保鲜现状与对策

1目前冬枣贮藏保鲜的主要问题1.1腐烂冬枣皮薄质脆,营养丰富,易受微生物侵染而导致腐烂。通过几年的探索和实践发现,冬枣在贮藏期间极易发生腐烂现象可分为两种情况:一种是由于机械伤引起的外部腐烂,主要发生在表皮、梗洼等伤口部位,在正常贮藏条件下发病时间是在贮藏之后的2个月左右,这种由机械伤感染引起的腐烂可通过在采收运输过程中减少出现伤口来控制,也可通过采后表面消毒措施来解决;另一种情况是由病原菌潜伏侵染而造成。病原菌在田间侵染果实(主要侵染期为花期和幼果期),之后一直潜伏在果实内,潜伏侵染的病原菌隐藏在冬枣果肉组织中…     

冬枣采后臭氧去感染技术研究

为了探索臭氧去感染技术对采后冬枣的贮藏保鲜效果,以冬枣为试材,研究不同臭氧浓度、不同处理次数、不同包装材料对其保鲜效果的影响。通过测定冬枣VC含量、硬度、可溶性固形物含量以及果品表面病菌数量、好果率,发现臭氧处理能够有效抑制冬枣的腐烂,延缓冬枣VC含量、硬度和可溶性固形物的下降。结果表明：臭氧处理冬枣的最佳浓度为40 mg/m3,可使冬枣的保鲜期达到120天,处理次数和包装材料对冬枣的保鲜效果影响较小。     

Control of blue mold decay of apple during commercial controlled atmosphere storage with yeast antagonists and sodium bicarbonate

A mixture of two yeast antagonists, Metschnikowia pulcherrima and Cryptococcus laurentii, originally isolated from apples and exhibiting greater biocontrol activity against blue mold of apple than either yeast applied alone, were used in combination with sodium bicarbonate (SBC) in a pilot test in which treated fruit were stored under commercial controlled atmosphere (CA) storage conditions. Conidia of Penicillium expansum, antagonists cells and SBC were added to the drench solution. The treatments were applied to apples by drenching entire bins filled with apples containing 100 wounded fruit evenly distributed among five positions in each bin. The treated fruit were stored in commercial CA storages for approximately six months in the 2005–2006 and 2006–2007 storage seasons and then evaluated for incidence of decay. In both years, the treatments with the antagonist alone or in combination with SBC were equally effective and reduced blue mold incidence by 84–97% in 2005–2006 and 73–82% in 2006–2007. SBC alone significantly reduced blue mold incidence compared to the non-treated control but was less effective than the antagonist alone or in combination with SBC. This pilot test showed that the combination of these two antagonists and SBC can be an effective decay control method under commercial CA conditions, confirming results from our earlier laboratory studies using similarly treated fruit stored under CA conditions.     

甜瓜采后病害生防细菌的鉴定及生理生化特性测定

分离筛选对甜瓜采后病害具有潜在防治效果的微生物,以建立甜瓜采后病害综合防治体系。采用生物测定的方法从甜瓜表面筛选生防菌株,应用16SrDNA序列分析,并结合生理生化指标的测定进行鉴定。结果表明,从甜瓜表面分离得到1株防治效果明显且稳定的生防菌株2-17,平板对峙测定菌株2-17对采后病害3种病原菌具有明显的拮抗作用;室内生物测定表明,菌株2-17对3种病原菌的防治效果都达到了极显著的水平,特别是对于Trichotheci-umroseum防治效果最好,达到87.5%;对Fusariumspp.和Alternaria alternata的防治效果分别为78.6%和70.8%。应用16SrDNA序列分析,初步鉴定2-17为假单胞属(Pseudomonas);通过形态学观察、革兰氏染色、鞭毛染色以及生理生化指标的测定,2-17鉴定为P.putidabiovar A。     

木薯干旱胁迫下离区发育相关基因MeAP2-2酵母单杂交文库构建及其上游调控基因的筛选

为了研究干旱胁迫下调节木薯叶片脱落相关的重要节点基因及其分子调控网络,以‘华南5号’木薯为实验材料,通过采用酵母单杂交筛选系统,将MeAP2-2启动子中激素与胁迫相关的元件串联后整合入酵母染色体,构建诱饵菌株;采用SMART技术进行离区cDNA文库的构建,将离区cDNA与pGADT7-Rec表达载体共同转化诱饵菌株,通过同源重组在酵母细胞内筛选MeAP2-2的上游转录调节因子;利用酵母菌落PCR法获得阳性克隆中的cDNA插入片段,测序后在JGI网站进行Blast分析。结果表明,构建的cDNA文库库容为1.5×106,插入片段大小为250~3000 bp。cDNA 插入片段经测序和Blast同源性分析和定量PCR分析,筛选出1个Metallothionein protein,1个Core histone protein,1个Heavy-metal-associated protein与MeAP2-2相关的调节因子。实验结果证明酵母单杂交文库构建成功,初步筛选获得了调节MeAP2-2的上游调节因子。为研究木薯干旱胁迫下离区发育的信号转导通路奠定了基础。     

Metschnikowia andauensis as a new biocontrol agent of fruit postharvest diseases

Potential antagonists were isolated from the epiphytic flora associated with oranges and pome fruit. A total of 1465 microorganisms were tested in a preliminary screening against blue and green moulds on pome and citrus fruit, respectively. Among them, approximately 3% reduced incidence and severity by more than 50% and 4 microorganisms fulfilled the selection criteria of reduction in severity and incidence by 75%. The most effective was a yeast identified as Metschnikowia andauensis, strain NCYC 3728 (PBC-2), isolated from the surface of ‘Bravo de Esmolfe’ apple fruit cultivated in North Portugal. The biocontrol activity of M. andauensis PBC-2 was dependent on its applied concentration. At 5 × 10⁶ cfu/mL incidence (% of infected wounds) and severity (lesion diameter) were reduced by 62 and 70%, respectively and at 1 × 10⁷ cfu/mL, the greatest reduction was achieved, 90% of incidence and 95% of severity. The broad spectrum of action of M. andauensis PBC-2 was evaluated with effective control being achieved against Rhizopus stolonifer, Penicillium expansum and Botritys cinerea, on ‘Rocha’ pears and on different apple cultivars and against Penicillium digitatum and Penicillium italicum on mandarins and oranges. In semi-commercial trials in cold storage, the reduction of blue mould was 90%. Rapid colonization of fresh apple fruit wounds was observed during the first 24 h of cold storage, followed by a significant population increase during the first 15 days of storage and then the population remained stable until the end of storage.     

烟草黑胫病拮抗细菌复合菌株的筛选与防治效果评价

从烟草根际土壤中筛选对烟草黑胫病菌(Phytophthora parasitica var. nicotianae)具有拮抗作用的细菌,并对拮抗菌株进行复配筛选,以期为烟草黑胫病的生物防治提供高效生防资源。从贵州省毕节市、四川省泸州市种植烟草的田地采集根际土壤样品,平板稀释法分离土壤细菌,平板对峙试验筛选对烟草黑胫病菌有拮抗作用的菌株,相容性试验测定亲和性较好的菌株组合,对获得的菌株和复配菌株进行进一步盆栽和大田试验,测定其对黑胫病的防治效果,并对拮抗效果较好的菌株进行16S rDNA鉴定。在采集到的17份土壤样品中共分离到247株细菌,初筛获得19株对烟草黑胫病菌有拮抗作用的菌株,相容性测定筛选出6株亲和性较好的拮抗细菌B3和B64、B41和B57以及L7和L47。进一步的抑菌、盆栽和大田试验表明以复配菌株B41B57和L7L47抑菌效果最佳,盆栽试验防治效果分别达到75.72%和77.95%,大田试验中防治效果分别达67.99%和71.40%,且复配菌株抑菌效果高于单一菌株。16S rDNA序列分析鉴定拮抗细菌B41为枯草芽孢杆菌(Bacillus subtilis),L7、L47为解淀粉芽孢杆菌(B. amyloliquefaciens),B57为恶臭假单胞菌(Pseudomonas putida)。复配菌株B41B57和L7L47对烟草黑胫病具有良好的防治效果,可作为烟草黑胫病生物防治的有效生防资源。     

黑龙江向日葵菌核病拮抗菌株的分离与筛选

为筛选出黑龙江向日葵菌核病的有效生防菌株,采集向日葵根围土、病株残体74份,采用土壤稀释平板法分离菌株和平板对峙培养初筛,共分离筛选出38株对向日葵菌核病有拮抗活性的生防菌株。通过菌核萌发抑制、离体叶片测试、温室盆栽试验复筛。结果表明,M1M2菌株表现最好,菌核萌发抑制效果和离体叶片防效均超过90%,其100 mL发酵原液处理土壤在温室盆栽中防效达83.52%,具备进一步研究应用的价值。     

库尔勒香梨腐烂病拮抗菌的筛选及其防效测定

筛选对梨腐烂病菌具有抑菌活性的拮抗细菌,明确其防病效果,为香梨树腐烂病的生物防治提供依据。从各种原料的果蔬酵素液和香梨枝条组织中分离细菌,采用平板对峙培养初筛和细菌发酵液复筛,测定分离菌株对香梨腐烂病菌(Valsa ceratosperma)的抑菌活性,从中筛选抑菌作用显著的拮抗菌株,通过离体枝条法测定其防病效果。筛选出对V. ceratosperma具有抑菌活性的12个细菌菌株,抑菌率为54.72%~86.43%。离体枝条法测定结果表明,分离自酵素液的拮抗细菌XG-FX22和G-FX12菌株的保护性防效分别达到了77.71%和65.29%,治疗性防效分别达到了66.71%和66.14%,防病效果显著高于其他菌株。通过形态学及16S rDNA序列分析,将G-FX12和XG-FX22菌株鉴定为贝莱斯芽孢杆菌(Bacillus velezensis)。研究结果为香梨腐烂病生防资源的发掘和病害的有效防控提供科学基础。     

拮抗酵母BS-316抑菌成分分离与应用的初步研究

以拮抗酵母菌BS-316为试材,研究酵母菌及其培养液对灰霉菌的抑菌性,用柱层析的方法对酵母培养液进一步分离纯化,并测定了粗提纯组分对灰霉菌的抑菌性。结果表明,酵母菌及其培养液对灰霉菌均有一定的抑制作用,酵母菌悬液对灰霉菌的抑菌性高于酵母培养液;酵母培养液经粗提取后,随着接种时间的延长,粗提纯组分对灰霉菌的抑制作用高于培养原液;活体试验中,粗提纯组分对番茄果实灰霉病的扩展有明显的抑制作用,其病斑直径显著小于酵母培养液处理(P0.05)。表明拮抗酵母菌BS-316除了细胞抑菌外,还可能产生了某些抑菌物质存在于培养液中,并且经纯化后可能用于果实灰霉病的防治保鲜。     

A new strain of Metschnikowia fructicola for postharvest control of Penicillium expansum and patulin accumulation on four cultivars of apple

The efficacy of three antagonistic yeasts, Metschnikowia pulcherrima strain MACH1, M. pulcherrima strain GS9, and Metschnikowia fructicola strain AL27, against Penicillium expansum and patulin accumulation was evaluated on apples stored at room (22 ± 1 °C for 7 days) and cold temperatures (1 ± 1 °C for 56 days). To increase the potential range of application of the biocontrol agents (BCAs), their efficacy was evaluated on four cultivars of apple, i.e. ‘Golden Delicious’, ‘Granny Smith’, ‘Red Chief’ and ‘Royal Gala’. AL27 was more effective than MACH1 and GS9 in the control of blue mold rot and in the reduction of patulin accumulation. The efficacy of AL27 was in most cases similar to the chemical control used, making the antagonist as competitive as chemical fungicides. In vitro experiments showed that AL27 reduced the conidial germination and germ tube length of P. expansum more than the other strains. The three BCAs were more effective in the control of blue mold rot on ‘Golden Delicious’ apples than on the other tested cultivars.