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A two-component cloning system to transfer foreign DNA into plants was derived from the octopine Ti plasmid pTiB6S3. pGV2260 is a non-oncogenic Ti plasmid from which the T-region is deleted and substituted by pBR322. pGV831 is a streptomycin-resistant pBR325 derivative that contains a kanamycin resistance marker gene for plant cells and a site for cloning(More)
Asparagus officinalis was the first monocotyledonous plant from which hormone-independent and opine-producing crown gall tissue could be isolated. We confirm by DNA hybridization that tumor lines obtained after infection of this plant by Agrobacterium strains harboring wild-type nopaline and octopine tumor-inducing (Ti) plasmids are stably transformed and(More)
Members of tribe Vandeae (Orchidaceae) form a large, pantropical clade of horticulturally important epiphytes. Monopodial leafless members of Vandeae have undergone extreme reduction in habit and represent a novel adaptation to the canopy environment in tropical Africa, Asia, and America. To study the evolution of monopodial leaflessness, molecular and(More)
It is widely recognized that we are entering an extinction event on a scale approaching the mass extinctions seen in the fossil record. Present-day rates of extinction are estimated to be several orders of magnitude greater than background rates and are projected to increase further if current trends continue. In vertebrates, species traits, such as body(More)
Fire may have been a crucial component in the evolution of the Cape flora of South Africa, a region characterized by outstanding levels of species richness and endemism. However, there is, to date, no critical assessment of the age of the modern fire regime in this biome. Here, we exploit the presence of two obligate post-fire flowering clades in the orchid(More)
The plastid coding rbcL and non-coding trnLF regions of 53 of 55 southern African Zygophyllum species were sequenced and used to evaluate the phylogenetic relationships within the southern African representatives of the genus. Published sequences of the same gene regions of Australian, Asian and North African Zygophyllum species were included to assess the(More)
The build-up of biodiversity is the result of immigration and in situ speciation. We investigate these two processes for four lineages (Disa, Irideae p.p., the Pentaschistis clade and Restionaceae) that are widespread in the Afrotemperate flora. These four lineages may be representative of the numerous clades which are species rich in the Cape and also(More)
Phylogenetic relationships were inferred for the African subtribe Disinae (Orchidoideae, Orchidaceae), which include the large genus Disa and the small genus Schizodium. One nuclear (ITS) gene region and two plastid (trnLF and matK) gene regions were sequenced for 136 ingroup, representing 70% of all known Disinae species, as well as for 7 outgroup taxa.(More)
In the Taita Hills in southern Kenya, remnants of the original Afromontane forest vegetation are restricted to isolated mountain peaks. To assess the level of degradation and the need for forest restoration, we examined how forest plant communities and their indicator species vary between and within remnant patches of cloud forest. We used ordinal abundance(More)
The large angraecoid orchid clade (subtribe Angraecinae sensu lato) has undergone extensive radiation in the western Indian Ocean, which includes Africa, Madagascar, and a number of Indian Ocean islands, such as the Mascarene Archipelago. To investigate systematics and biogeography of these Mascarene orchids, phylogenetic relationships were inferred from(More)