短果杜鹃组培快繁及其种质试管保存培养基的筛选

以短果杜鹃新生嫩芽为外植体,应用均匀设计法筛选其基部直接再生芽苗、生根及其试管苗保存培养基,结果表明,最适合的基部直接再生芽苗诱导培养基为:DR+2-ip 2.75 mg·L-1+IAA0.07 mg·L-1;生根培养基:1/2MS(大量元素)+IAA0.1 mg·L-1+NAA0.05 mg·L-1+Kt0.2mg·L-1;试管苗保存培养基:1/SMS+根皮苷5.0mg·L-1.短果杜鹃组织培养的不同阶段需要不同的培养基,常温条件下,利用"低营养延缓生长"的方法在试管内保存其种质.     

均匀设计法优化短果杜鹃高效快繁体系

［目的］建立短果杜鹃高效快繁体系,实现短果杜鹃的高效离体快繁。［方法］以短果杜鹃嫩茎段为外植体,应用均匀设计法筛选最适合的培养基。［结果］最适合嫩茎段的腋芽萌发及生根的最佳培养基为MS（改良）＋IAA 0.15 mg/L ＋IBA 0.30 mg/L ＋GA3 3.00 mg/L,再生率达92%以上。以再生植株的茎节为材料进行快繁的结果表明,在35 d的1个培养周期内增殖倍数平均达45以上。［结论］该研究建立了短果杜鹃的高效快繁体系,为长白山高山杜鹃的开发利用和工厂化育苗提供了依据。     

一种促进短果杜鹃种子萌发的前处理方法——二次浸种法

[目的]筛选出促进短果杜鹃种子萌发的前处理方法,提高短果杜鹃种子发芽率.[方法]采用培养皿滤纸法,比较不同浓度的GA3、聚乙二醇（PEG）浸种以及二者复合浸种（二次浸种）对短果杜鹃种子萌发的影响.[结果]适宜浓度的GA3、PEG浸种及二次浸种均可有效促进短果杜鹃种子萌发.其中,400 mg/L GA3与浓度10％ PEG-6000分别浸种24h以及500 mg/L GA3与浓度10％ PEG-6000分别浸种24h这2个组合处理的短果杜鹃种子萌发芽率、发芽势、发芽指数最高,在0.05水平显著高于其他处理.[结论]二次浸种法（400 mg/L GA3与浓度10％ PEG-6000分别浸种24h或500 mg/L GA3与浓度10％ PEG-6000分别浸种24h）是促进短果杜鹃种子萌发的最优前处理方法.     

Wild tuber-bearing species ofSolanum and incidence ofPhytophthora infestans (Mont.) de Bary on the western slopes of the volcano Nevado de Toluca. 1.Solanum species

Summary During the period 1982–87, wildSolanum species were surveyed in an area of 15000 ha by observations and collections along five long (10 km) transects covering altitudes from 2900 to 3900 m, and twelve short (300 m) transects. The sevenSolanum species,demissum (dms), verrucosum (ver), iopetalum, brachycarpum, x edinense, stoloniferum and an unidentified species, possibly a sterile hybrid betweendms andver, grew patchily and their many small colonies formed part of a complex plant community that changed in composition with altitude and topography. The most frequent species wasdms (80%), while other species often grew in mixed colonies with it. As the altitude increased, so did the distances between colonies, whereas species diversity decreased and above 3500 m onlydms was found. Most species propagated both clonally, through tubers on long stolons, and sexually through botanical seed.