竹丛枝病的研究Ⅱ病原菌的形态及其生物学特性

病菌无性子实体—病枝端部米粒状的假子座,一年中产生三批。分生孢子萌发仅从两端细胞伸出芽管,中间的细胞不萌发。子囊壳埋生于假子座一侧的子座中,较少产生,子囊孢子细长,萌发时在两侧可产生多个芽管,断裂后的子囊孢子也能正常萌发。萌发适温都为25℃左右,分生孢子需相对湿度100％,子囊孢子需92％以上才能萌发良好。它们的萌发力都只能保持在25天左右。     

泡桐丛枝病发生相关蛋白质的电泳分析

对毛泡桐和白花泡桐同龄同方位的病株健叶，病株病叶和健株健叶蛋白质进行了单向和双向SDS聚丙烯酰胺凝胶电泳分析研究。单向电泳结果表明，毛泡桐和白花泡桐病株健叶，病株病叶和健株健叶的蛋白质在种类和数量上存在一定的差异。其明显的蛋白质凝胶扫描谱带分别有22、20和17以及27、21和22条；双向电泳结果表明，毛泡桐与白花泡桐在健株健叶，病株健叶和病株病叶蛋白质变化方面具有一定相似性，即在两种泡桐健株健叶和病株健叶中存在的一种pI6.8,MW24KD蛋白多肽在病株病叶中观察不到。我们认为这种情形可能与发生泡桐丛枝病有一定的关系。     

泡桐丛枝病类菌原体(MLO)病原传染长春花研究初报

菟丝子(Cuscuta spp.)是一种寄生植物,利用菟丝子为介体可以将植物病毒或类菌原体(mycoplasma like organism)从一株植物传染到另一株植物上。杨一朗陈景耀分别用大豆菟丝子和南方菟丝子为媒介成功地将甘薯丛枝病从甘薯传到长春花上,产生花器叶化、侧枝丛生病状。     

罹丛枝病泡桐组织结构的解剖观察

泡桐在罹丛枝病之后，除节间距缩短、叶片缩小等外部变化外，其组织结构也发生变化。罹病枝的顶芽弱化；茎形成层明显变薄；次生木质部导管变细；叶脉木质化程度降低；叶肉中的栅 栏组织变薄，叶背毛刺数量减少。结构性变化造成了水份“供给“与“消耗”以及光合作用与呼吸作用的生理矛盾。矛盾的加剧可能导致了枝条或幼树的死亡。     

Participatory modelling to enhance social learning,collective action and mobilization among users of the mafungautsi forest,Zimbabwe

Participatory modelling can be a useful process to encourage critical examination of livelihood options and foster sustainable natural resource use through enhanced social learning, collective action and mobilization. The broom-grass group in the Mafungautsi Forest Reserve serves as a case study of the process and outcomes of such participatory modelling. Innovative group facilitation methods enhanced participation in the modelling process. The modelling process complements broader efforts to achieve higher levels of adaptive collaborative management. This work was conducted as part of the Adaptive Co-Management project of CIFOR, the Center for International Forestry Research. We are grateful to the UK’s Department for International Development (DFID) and the European Community for financial support of this project.     

海南岛假臭草入侵情况及丛枝病发病情况研究

对海南岛18市县假臭草入侵情况进行普查,从中选取8个地区,对假臭草丛枝病的发病情况进行重点调查,结果表明:海南18市县均存在假臭草,8个地区均存在假臭草丛枝病,其发病率为0.37%～3.01%,发病指数为0.31～2.59。对健康株高与丛枝病株高进行差异性分析,结果表明:假臭草丛枝病可以显著抑制假臭草的生长。     

荔枝鬼帚病及其与龙眼鬼帚病相关性的初步研究

 荔技鬼帚病(LiWBV)可侵染不同品种和不同龄期的荔枝,引起幼叶卷缩似月牙形、侧枝丛生呈扫帚状、花穗密集成簇生等症状。在电镜下首次在病叶内找到线状病毒粒体。该病症状和病原形态与龙眼鬼帚病(LWBV)相似,媒介昆虫同是荔枝蝽,通过该昆虫介体,LiWBV和LWBV均可传到两种寄主植物上。由此推断,两种病害可能是由同种病毒侵染所致。     

Characterization of a phytoplasma associated with witches' broom disease of potatoes in Korea

 Symptoms of witches' broom disease caused by phytoplasma, including general stunting and yellowing, were observed in potatoes (Solanum tuberosum L.) in a storehouse on Jeju Island, Korea in 1998. Based on sequence analysis of DNA products from polymerase chain reaction (PCR)-amplified 16S ribosomal DNA and 16S–23S spacer region using universal phytoplasma primers, the phytoplasma associated with potato witches' broom disease (PWB) was identified as a member of 16S-group VIII. It was most closely related to elm AH phytoplasma (99.7% similarity, accession no. AF268895), which is in the clover proliferation (CP) subgroup. This report is the first from the East Asian continent of a plant pathogenic phytoplasma belonging to the CP subgroup and includes the nucleotide sequence of most of the potato phytoplasma 16S rDNA. Received: May 1, 2002 / Accepted: July 1, 2002     

A Leafhopper (Hishimonus sellatus) Transmits Phylogenetically Distant Phytoplasmas: Rhus Yellows and Hovenia Witches' Broom Phytoplasma

Phytoplasmas causing a severe decline of three tree species, i.e., Rhus javanica, Hovenia tomentella and Zizyphus jujuba, in Japan were examined for their transmissibility by a leafhopper species Hishimonus sellatus, and for their phylogenetic relatedness. By H. sellatus, Rhus yellows (RhY) phytoplasma was transmissible to white clover and periwinkle seedlings, causing typical symptoms in these plants. Jujube witches' broom (JWB) phytoplasma was also transferred to the host plant, Z. jujuba, by the leafhopper. Because JWB phytoplasma was transmitted to Hovenia tomentella and caused the same symptoms as Hovenia witches' broom (HWB), JWB phytoplasma may be very closely related to HWB phytoplasma. RFLP analysis of the PCR products of 16S rDNA revealed that RhY phytoplasma belongs to the Aster yellows (AY) group, and JWB and HWB phytoplasmas belong to a different group (possibly Elm yellows group). Thus, we found that one species of leafhopper can carry phylogenetically distant phytoplasmas. Received 23 April 2001/ Accepted in revised form 29 October 2001