糖槭叶枯病发病规律及防治

糖槭叶枯病 Phyllosticta negundinis病菌孢子放散开始期和高峰期与每年的温、湿度变化有关。病害发生严重程度与降雨量关系密切 ,降雨早且量大时病害严重。病菌以分生孢子器和分生孢子在病叶上越冬 ,通过气流传播成为翌年初侵染源。喷洒 70 %甲基托布津可湿性粉剂 10 0 0倍液和 75%百菌清可湿性粉剂 80 0倍液均能收到较好的效果     

一次防治大豆灰斑病籽粒灰斑

通过室内及田间大豆不同生育期接种试验证明，籽粒感染灰斑病的关键时期是Ｒ３－Ｒ５期．Ｒ２期以前侵染不造成籽粒斑驳，据此提出一次防治大豆籽粒灰斑病的关键时期为Ｒ２－Ｒ４期．     

Morphological characterization of the interaction between Diplocarpon rosae and various rose species

Blackspot, caused by Diplocarpon rosae , is the most severe and ubiquitous disease of garden roses, but information is lacking about genotype-specific forms of resistance and susceptibility of the host. Macro- and microscopic analyses of 34 rose genotypes with a defined monoconidial culture black spot inoculum identified susceptible and resistant rose genotypes and further genotype-specific subdivisions, indicating the presence of partial forms of resistance and different resistance mechanisms. In total, eight interaction types were characterized, five representing compatible (types 1–5) and three representing incompatible interactions (types 6–8). The incompatible interactions were characterized by the lack of any visible fungal structures beneath the cuticle (type 8), single-cell necroses (type 7) or necroses of larger cell clusters (type 6), the latter two types with penetration hyphae and haustoria in epidermal cells.     

Pelargonium flower-break and pelargonium line pattern viruses in the Netherlands; purification,antiserum preparation,serological identification,and detection in pelargonium by ELISA

Two viruses, detected frequently in the Netherlands in pelargonium, were identified by serology and test plant reactions. Antisera were prepared and an ELISA procedure was developed to detect the viruses in pelargonium.One of the viruses, PFBV-N, proved to be pelargonium flower-break virus. With the antiserum to PFBV-N, it could be detected reliably throughout the year inPelargonium zonale Springtime Irene.The other virus, PLPV-N, was serologically closely related to pelargonium line pattern virus (PLPV) and to pelargonium ring pattern virus (PRPV), as were an old virus isolate from Saturnus, collected in the Netherlands in 1971 (L128), and PLPV isolates from Yugoslavia (PLPV-Y) and Denmark (PLPV-D). There were only minor differences in host-plant reactions between the virus isolates. Based on these tests, PLPV and PRPV are considered as isolates of the same virus, for which, for practical reasons, the name pelargonium line pattern virus is proposed.PLPV could be reliably detected by ELISA inP. zonale Springtime Irene and Amanda throughout the year with only a few exceptions. InPelargonium peltatum Tavira, however, reslts were erratic due to uneven distribution of virus in the plant. Best results were obtained when petioles of fully expanded leaves were tested.     

甜樱桃芽酚类物质含量及相关酶活性变化与自然休眠的关系

 以7年生甜樱桃‘红灯’和‘早红宝石’为试材, 研究了酚类物质含量及相关酶活性在自然休眠期间的动态变化, 探讨了温度对酚类物质含量的影响。结果表明, 甜樱桃芽酚类物质在自然休眠期间持续缓慢增加, 随休眠的结束, 含量急剧下降, 不同品种之间有差异, 自然休眠结束后总酚含量降至最低。花芽中的酚类物质含量略高于叶芽, 多酚氧化酶( PPO) 、苯丙氨酸解氨酶( PAL) 活性差别不大; 不同需冷量的品种之间差异明显。芽中PAL活性与总酚含量的变化趋势呈正相关。而PPO活性在自然休眠期间逐渐升高。低温(5℃) 促进酚类物质的积累, 中期使其提前达到高峰并进入下降阶段, 后期加速其降低;高温(20℃) 效果相反, 变温(5℃/20℃) 效果不明显。     

梨新品种‘花盖王’

 ‘花盖王’是从‘花盖梨’中选出的梨四倍体芽变新品种。该品种除保持‘花盖梨’的优质、丰产、抗寒等优良性状外，最突出特点是果实大，单果质量是‘花盖梨’的2倍多，最大为250 g。     

Movement of Xanthomonas campestris pv. vitians in the stems of lettuce and seed contamination

Xanthomonas campestris pv. vitians , the causal agent of bacterial leaf spot of lettuce (BLS), can be seedborne, but the mechanism by which the bacteria contaminates and/or infects lettuce seed is not known. In this study, the capacity of X. campestris pv. vitians to enter and translocate within the vascular system of lettuce plants was examined. The stems of 8- to 11-week-old lettuce plants were stab-inoculated, and movement of X. campestris pv. vitians was monitored at various intervals. At 4, 8, 12 and 16 h post-inoculation (hpi), X. campestris pv. vitians was recovered from 2 to 10 cm above (depending on stem length) and 2 cm below the inoculation site. Xanthomonas campestris pv. vitians was also recovered from surface-disinfested stem sections of spray-inoculated plants. Together, these results are consistent with X. campestris pv. vitians invading and moving systemically within the vascular system of lettuce plants. To investigate the mechanism of seed contamination, lettuce plants at the vegetative stage of growth were spray-inoculated with X. campestris pv. vitians and allowed to develop BLS. Seed collected from these plants had a 2% incidence of X. campestris pv. vitians external colonization, but no bacteria were recovered from within the seed.     

Genetic variability within Phaeoisariopsis griseola from Central America and its implications for resistance breeding of common bean

The genetic and virulence variability of 112 isolates of Phaeoisariopsis griseola , collected from various locations in Central America, were studied using seven random amplified polymorphic DNA (RAPD) primers and 12 common-bean differential genotypes. Broad molecular diversity ( H  = 0·92) among isolates was found using RAPD markers. Fifty pathotypes were identified on 12 differential bean genotypes, 29 of which were represented by only one isolate. Only 18 pathotypes were found in two or more countries. Pathotype 63-63 was the most virulent and caused leaf spots on all 12 common-bean differential genotypes. Comparison of virulence phenotypes and RAPD profiles to known Andean P. griseola isolates confirmed that all isolates belonged to the Mesoamerican group. Pairwise comparison between individual RAPD loci showed that the majority were in gametic phase linkage disequilibrium, revealing that P. griseola maintains a genetic structure that is consistent with asexual reproduction. The molecular and virulence diversities of P. griseola isolates from Central America imply that using single resistance genes to manage angular leaf spot is inadequate and stacking resistance genes may be necessary to manage the disease effectively.     

几种落叶果树H2O2含量变化与自然休眠关系的研究

 以设施栽培中常见的几种核果类果树品种和两个葡萄品种为试材, 分析了芽休眠期间 H₂O₂含量变化动态, 并探讨了温度、生长调节剂及化学破眠物质对H₂O₂含量影响的效应。结果表明: 休眠期间,不同树种( 品种) 芽内 H₂O₂含量存在差异, 基本趋势是晚熟品种高于早熟品种, 花芽高于叶芽, 但葡萄品种相反, 早熟的‘京秀’高于晚熟的‘巨峰’; 休眠期芽内 H₂O₂含量基本呈稳步上升后急剧下降的趋势,不同品种急剧下降的时间略有差别, 且与自然休眠解除的时间相吻合。低温(5 ℃) 处理显著增加了芽中 H₂O₂含量, 中温(10 ℃) 使 H₂O₂含量略有增加, 而高温(20 ℃) 却导致 H₂O₂含量降低。休眠前期50 mg.L^-1 ABA 处理显著提高了芽中H₂O₂含量, 而100 mg.L^-1的GA₃和6-BA 处理有减少 H₂O₂含量的趋势, 但二者差异不明显。热带地区常用的化学破眠物质对芽 H₂O₂的影响因树种( 品种) 、使用时期不同而异, 硫脲、KNO₃前期使用对核果类果树影响明显, CaCN₂对核果类无明显效应, 但对葡萄品种作用显著。果树芽 H₂O₂含量的动态变化表明, H₂O₂可能是低温解除自然休眠的原因。     

极早熟葡萄新品种‘90- 1’

 ‘90- 1’是从‘乍娜’的芽变中选出的葡萄新品种。该品种除保持母本的优质、丰产、适合保护地栽培等优良性状外, 其最突出的特点是极早熟, 果实6 月下旬成熟, 果实发育期仅35 d。