来源于产黄青霉病毒科成员的分离物对梨轮纹病菌生长及其致病力的影响北大核心CSCD

【目的】明确产黄青霉病毒科成员(Botryosphaeria dothidea Chrysovirus 1,BdCV1)对寄主梨轮纹病菌(Botryosphaeria dothidea)菌株生物学性状的影响,证实单独感染BdCV1梨轮纹病菌分离株是弱毒菌株;以期确定BdCV1是否为引起梨轮纹病菌弱致病力的单一因子。【方法】从前期弱致病力复合感染双分体病毒科成员Bd PV1和BdCV1的梨轮纹病菌LW-1中经多代菌丝分离获得的疑似仅单独感染BdCV1分离株(命名为LW-C)为材料;采用dsRNA检测、RTPCR,鉴定LW-C菌株中仅携带BdCV1。采用菌丝块接种于PDA培养基以及3针针刺法接种梨果实,观察其菌落形态以及发病情况,测定菌落生长速度和致病性,明确LW-C生物学特性。将LW-C对无毒菌株Mock进行水平转染,检测其传染后衍生菌株的dsRNA并测定其生物学特性。【结果】证实了LW-C仅感染BdCV1,具有弱毒特性;水平转染结果明确了BdCV1因子对梨轮纹病菌的菌落形态、生长速度有抑制作用,对寄主有弱致病力。【结论】确认了BdCV1是引起梨轮纹病菌致病力衰退的主要因子,为真菌病毒防治果树轮纹病害提供了新颖的生防材料。     

梨轮纹病菌弱毒株携带产黄青霉病毒水平传染力测定

梨轮纹病是由葡萄座腔菌（Botryosphaeria dothidea）引起。前期获得了感染葡萄座腔菌产黄青霉病毒（Botryosphaeria dothidea chrysovirus 1,BdCV1）引起弱毒的梨轮纹病菌菌株LW-C和LW-1，为进一步明确BdCV1介导弱毒菌株是否具有作为候选田间生防资源的潜力，将LW-C和LW-1分别与地理来源不同的梨轮纹病菌（B. dothidea）分离株和危害梨树严重的梨腐烂病菌（Valsa pyri）分离株XJ-28进行对峙培养试验，测定获得携带病毒的衍生菌株生长速率及致病力。研究结果显示轮纹病菌菌株弱毒因子BdCV1均能以一定频率水平传染至不同种类致病菌株中，可引起部分受体菌株生长速率下降，不同程度地抑制其生长。接种梨枝条和果实，原始受体菌株所形成病斑扩展长度约为带毒衍生菌株的2倍至4倍，表明病毒可抑制其受体菌株致病力。以上研究结果揭示了BdCV1可水平传染至不同种类受体菌株中，寄主范围广，具有作为生防因子应用于梨真菌病害中的可行性。     

5种细菌对苹果轮纹病菌菌丝的拮抗作用

作者在前期试验的基础上筛选出5种(茎1、茎2、茎4、花2、姜4)对苹果轮纹病菌菌丝有明显抑制作用的内生细菌,并通过与苹果轮纹病的对峙培养试验,对其进一步的筛选。结果表明,对苹果轮纹病菌菌丝生长抑制效果最好的为从黄顶菊内分离出的花2,其次为从姜内分离的姜4和从黄顶菊内分离的茎2,抑制效果最差的则为从黄顶菊内分离的茎1。     

Detached Cane Assay of Resistance to Botryosphaeria Cane Canker (Botryosphaeria dothidea) in Eastern U.S. Blackberry Genotypes

Abstract

Resistance to Botryosphaeria cane canker in blackberry (Rubus subgenus Rubus Watson) was studied in eleven cultivars (‘Apache’, ‘Arapaho’, ‘Chester Thornless’, ‘Chickasaw’, ‘Illini Hardy’, ‘Kiowa’, ‘Navaho’, ‘Ouachita’, ‘Prime-Jim?’, ‘Shawnee’ and ‘Triple Crown’) using a detached cane assay. Ends of stem segments were sealed with wax and wound-inoculated using squares of media with mycelium. Segments were kept in humid containers on a lab bench and reaction was evaluated ten days after inoculation by measuring the area of the resulting lesion. ‘Chicaksaw’ was found to be the most susceptible by this assay, while ‘Arapaho’ and ‘Triple Crown’ were found to be the most resistant.     

不同化学药剂对苹果轮纹病保护作用持效期快速测定方法的建立

以"富士"品种的苹果幼果和2年生枝条为试材,采用孢子萌发法,建立不同化学药剂对苹果轮纹病菌保护作用持效期的快速检测方法,研究80%代森锰锌可湿性粉剂和80%多菌灵可湿性粉剂在室内外条件下保护作用的持效期。结果表明:采用菌龄为10~15d的苹果轮纹病菌所产生的孢龄为1~3d的分生孢子,在28℃恒温黑暗条件下萌发6h后镜检孢子萌发率为适宜的孢子萌发体系。在室内和室外条件下,2种供试药剂在苹果幼果和2年生枝条上对轮纹病菌的保护作用均随时间的延长而降低,但相同条件下80%代森锰锌可湿性粉剂的保护作用优于80%多菌灵可湿性粉剂。室内条件下,80%代森锰锌可湿性粉剂在幼果和2年生枝条上的保护作用防效高于70%的持续时间为3d,7d后的防效仅为30%左右;在室外条件下,80%代森锰锌可湿性粉剂在幼果和2年生枝条上的保护作用随时间延长下降明显,但在幼果表面的防效下降速度显著慢于在2年生枝条表面的下降速度。该方法为快速评价不同化学药剂保护作用的持效期提供了手段。     

辽宁省苹果轮纹病病原菌鉴定及苹果品种(系)对其抗性的评价

从感染苹果轮纹病的苹果枝干获取分离物,进行培养与纯化,采用形态学、病原菌致病性和分子生物学3种方法相结合进行鉴定。结果表明,苹果轮纹病病原为葡萄座腔菌(Botryosphaeria dothidea)。同时,对16个苹果品种(系)对苹果轮纹病的抗性进行评价,筛选出2份稳定高抗苹果轮纹病试材—‘鸡冠’和74-178。     

精胺对梨花粉原位萌发及花粉管生长的影响

为进一步研究活体条件下精胺对梨花粉萌发及花粉管生长的影响,以幸水、新雪、长-二十世纪为材料,采用荧光显微镜观测了不同浓度精胺处理的花粉萌发及花粉管生长情况。试验结果表明:较低浓度的精胺能促进花粉萌发,而超过一定浓度时则表现抑制作用,适宜于花粉萌发的精胺浓度是0-0.025mmol/L。精胺对花粉管生长的促进作用因品种而异,0-0.05mmol/L,精胺促进幸水、新雪花粉管生长的作用主要表现在花柱中上部;而到达基部的花粉管仍较少,与对照间差异不显著。在0-0.025mmol/L的适宜浓度下,精胺可促进长-二十世纪花粉管生长并到达花柱基部。不同浓度的精胺对幸水、新雪坐果影响不大;而适宜浓度的精胺可促进长-二十世纪坐果。     

套袋对富士苹果轮纹病炭疽病的影响

通过采用不同时期套袋的方法 ,研究了富士苹果轮纹病和炭疽病的侵染规律。结果表明 ,富士苹果自谢花后 7～11d轮纹病开始感染 ,花后 2 3～ 2 7d为侵染高峰 ;而炭疽病菌的侵染高峰期为花后 2 7～ 4 3d。适期套袋 (花后 7d)可有效防治此 2种病害的为害     

不同生长和结果特性砂梨品种棚架栽培适应性初探

【目的】探明不同生长特性类型砂梨品种棚架栽培的适宜定植密度及整形修剪方法。【方法】选择‘蜜雪梨’‘黄花’‘翠冠’‘翠玉’和‘若光’5个代表4种不同生长结果特性类型的砂梨品种,进行棚架栽培适应性比较试验。【结果】长势弱、成枝力强类型代表品种‘翠玉’的成枝数量显著高于其他类型的代表品种,但成枝长度和粗度上均显著低于其他品种,各类型代表品种间上架能力存在差异;长势强、成枝力较强或中等的‘蜜雪梨’‘黄花’‘翠冠’3个品种则表现出较强冠层形成能力;‘蜜雪梨’‘黄花’和‘翠玉’,因成枝力强、长枝成花率高,早期产量形成能力更强,进入盛产期所需的时间短。【结论】长势强且成枝力较强或中等的品种适用较大株行距定植和级次多、树冠大的棚架树形进行整形;长势弱、成枝力强的品种适用较小株行距定植和级次少、树冠小的简易棚架树形进行整形;长势弱、成枝力弱的品种亦选择较大株行距定植和级次多、冠幅大的树形,其整形修剪过程中宜加大刻伤引芽方法的应用和注重徒长枝保护利用。     

Effects of polyethylene bags,ethylene absorbent and 1-methylcyclopropene on the storage of Japanese pears

Summary

Storage of the ‘Nijisseiki’ cultivar of Japanese pears was studied over three seasons for periods up to 36 weeks at 0°C. Storage in 50 μm thick low-density polyethylene (LDPE) bags at 0°C considerably delayed yellowing in all experiments, even after fruit was removed to 20°C for 1 week at the end of storage. The addition of an ethylene absorbent made from potassium permanganate on aluminium oxide (Purafil II) further delayed yellowing. Carbon dioxide levels in both treatments varied, but were generally in the range 2–3%. Oxygen levels remained high, generally 16–19%. In bags without Purafil, ethylene levels rose slightly during storage and were generally about 0.15 μl l^–1. When Purafil was included in the bags, the ethylene level was reduced 10-fold or more. A sensory test indicated that the use of LDPE bags and ethylene absorbent resulted in fruit with better eating quality than fruit stored in air. Disorders over the 3-year investigation were low even after long-term storage. The use of polyethylene bags reduced the severity of flesh browning, and flesh spot decay was virtually absent. The use of bags increased the severity of core browning. Inclusion of an ethylene absorbent in bags reduced the severity of disorders, particularly core browning. Treatment of the fruit with 1-methylcyclopropene (1-MCP), before or during storage, resulted in higher ethylene levels in the polyethylene bags. At the concentrations used, 1-MCP did not improve the storage of ‘Nijisseiki’ compared to the use of polyethylene bags with Purafil II.     

自发气调包装对‘新梨7号’果实品质及耐贮性的影响

【目的】明确不同厚度的保鲜袋自发气调包装对‘新梨7号’采后生理和贮藏品质的影响。【方法】将‘新梨7号’分别采用厚度为0.02、0.03、0.04和0.05 mm的PE袋扎口处理形成自发气调环境,于温度(0±0.5)℃、相对湿度90%~95%条件下贮藏,并以0.02 mm PE袋不扎口为对照处理,定期测定各处理相关指标,并统计果实腐烂率、果柄保鲜指数。【结果】不同厚度保鲜袋内气体成分在第30天时达到平衡,气调能力水平由高到低依次为0.05 mm>0.04 mm>0.03 mm>0.02 mm PE袋,采用上述包装进行自发气调处理均能够抑制果皮h°值、Fm、Fv和Fv/Fm的下降;果柄保鲜指数随保鲜袋厚度增加显著升高,果实腐烂率显著低于对照;显著降低果实维生素C含量,冷藏后期货架期间各处理果实硬度、可滴定酸含量显著高于对照。各处理乙醛含量极低,乙醇检测不出。【结论】‘新梨7号’为较耐CO2且极不易发生褐变的梨果品种。筛选出适合‘新梨7号’自发气调包装袋为0.03 mm PE袋,可有效保持果面绿色,降低果实腐烂率但显著降低维生素C含量。     

Effect of Paecilomyces cicadae polysaccharide on duplication of hepatitis B virus in HepG2.2.15 cell strain

AIM: To investigative the inhibitory effects of Paecilomyces cicadae polysaccharide (PcPS) against HBV in vitro, and the effects on the Toll like receptor 4 (TLR4) mRNA expression in HepG2.2.15 cell strain. METHODS: HepG2.2.15 cell strain was co-cultured in vitro with PcPS in different concentrations, and lamivudine (LMV) was applied as positive control. MTT assay was employed to detect the cytotoxicities of PcPS in vitro, when the HepG2.2.15 cells was used as target cells. The effects of PcPS on the secretion of HBsAg and HBeAg were assayed by ELISA method. Fluorescence quantitative-PCR (FQ-PCR) was used to detect the inhibitory effects of PcPS on the content of HBV-DNA and TLR4 mRNA in HepG2.2.15 cells. RESULTS: The inhibitory effects of PcPS on the HBsAg and HBeAg were observed and the maximum inhibitory ratio up to 44.8% and 31.0%, respectively. The same inhibitory effects of PcPS on the HBV-DNA replication and TLR4 mRNA expression in HepG2.2.15 cells were also found. CONCLUSION: A certain concentration of PcPS significantly inhibits HBV replication in vitro.