Apostasioideae jsou nejmenší, vývojově nejpůvodnější a současně nejméně prozkoumanou podčeledí vstavačovitých (Orchidaceae). Vyskytují se ve dvou rodech a 17 druzích v podrostu tropických lesů v jihovýchodní Asii. Od ostatních orchidejí se liší mj. specifickou květní morfologii a pylovými zrny nespojenými v brylky. Studium jaderného genomu ukázalo, že Apostasioideae mají jedny z nejmenších genomů mezi orchidejemi a jejich DNA je velice bohatá na adenin a thymin. Skupina je mimo svoji domovinu prakticky nepěstovatelná a chybí proto i ve velkých specializovaných sbírkách., Apostasioideae is the smallest, least specialized orchid subfamily, which is still largely unexplored. It encompasses 17 terrestrial species in two genera native to tropical rain forests of SE Asia. They differ from other orchids in their unique floral morphology and pollen shed in monads. Our flow cytometric analyses showed that apostasioids possess very small genomes with a considerable proportion of adenine and thymine. The lack of information stems at least partly from their extremely difficult cultivation outside native areas., and Jana Jersáková, Jan Ponert, Pavel Trávníček, Jan Suda.
Genomy eukaryotických organismů se nesmírně liší svou velikostí, kdy dosahují až 66tisícinásobného rozdílu. Největší v současnosti známý genom byl nalezen u vraního oka japonského (Paris japonica), nápadné byliny z Japonska. Množství jaderné DNA u tohoto druhu bylo odhadnuto na 153,32 pg, jeho genetický kód je tak 50krát delší než ten lidský., Genomes of eukaryotic organisms vary tremendously in size, spanning an approximately 66,000-fold range. Recently the largest genome has been discovered in Paris japonica, a striking plant native to Japan. The amount of nuclear DNA was estimated at 153.32 pg, making the genetic code 50 times longer than that of a human being., and Jan Suda.
Water-lilies (the genus Nymphaea) are one of the most ancient groups of aquatic plants. Two species (N. alba and N. candida) are native to the flora of the Czech Republic, both are critically endangered. Morphological similarities, large phenotypic variation and putative interspecific hybridization pose difficulties for species identification. The amount of nuclear DNA was found to be a reliable characteristic that allows not only species but also their hybrids to be re - cognized. Native species are mainly threa - tened by the loss of suitable habitats and planting of garden cultivars in natural sites. and Klára Kabátová, Petr Vít, Jan Suda.
The flora of the CR harbours 48 endemic (sub)species of vascular plants (plus 26 taxa considered as near-endemic). Most of them occur above the timberline in the High Sudetes Mts. while others are restricted to lowland habitats with specific edaphic or topographic features (serpentine outcrops, calcareous fens, rocks in steep river valleys). Apomicts clearly prevail (49 taxa, especially Hieracium and Sorbus). All endemics are evolutionarily young (neoendemics) and their origin is mostly associated with the Quaternary climatic oscillations. and Jan Suda, Zdeněk Kaplan.
New insights into the evolutionary processes that have fostered the species richness of Cape flora (in particular genome duplication) have been gained by Czech researchers during the last few years. Pleasures and pains of botanical research in this world biodiversity hotspot are summarized. and Jan Suda.