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.
Dendrobium is one of the three largest genera in the Orchidaceae and is distributed throughout various habitats. We investigated photosynthesis in seven Dendrobium species and cultivars by comparing their leaf δ13C values, titratable acidity, and CO2 exchange in well-watered and drought-stressed conditions. In addition, the leaf thickness and mesophyll succulence index (Sm) were measured in well-watered conditions. Our results indicate that Dendrobium loddigesii is a typical obligate (or constitutive) CAM plant because the leaf δ13C values were -14.47 and -14.66‰ in both conditions, respectively. Others showed the leaf thickness of 0.31-0.89 mm and their δ13C values ranged from -25.68 to -28.37‰. These are not the CAM plants but they could not be classified as obligate C3 or C3/CAM intermediate plants. Dendrobium crepidatum and Dendrobium fimbriatum were further identified as the obligate C3 plants because the net CO2 uptake was positive during daytime and negative during nighttime in both conditions. In contrast, Dendrobium chrysotoxum, Dendrobium nobile, and D. nobile ‘V1’ and ‘V4’, showed no positive net CO2 uptake and low ΔH+ values during nighttime under well-watered conditions, indicating C3 photosynthesis. However, they showed the positive net CO2 uptake and large ΔH+ values during nighttime after drought-stress (21 or 28 days without H2O), indicating CAM photosynthesis. Therefore, these four species and cultivars were identified as C3/CAM intermediate (inducible or facultative) plants. In brief, obligate CAM, C3/CAM intermediate, and obligate C3 plant types all exist in the section of Dendrobium. To the best of our knowledge, this is the first report of the obligate C3 plants in Dendrobium, and these diverse photosynthetic pathways may explain their varied environmental adaptations., S. Qiu, S. Sultana, Z. D. Liu, L. Y. Yin, C. Y. Wang., and Obsahuje bibliografii
Chyliza vittata is known to utilize leaves, stems and underground parts of several leafy and leafless orchids. Compared to the well-recorded feeding habits of C. vittata in Europe, its feeding habits in Japan are poorly studied. Thus, further records of its host plants and the habits of its larvae in Japan are likely to reveal the similarities and differences in its feeding habits in Europe and Japan. The current study reports C. vittata feeding on the stems of the mycoheterotrophic orchid Yoania japonica in central Japan. This study also showed that in spite of the small size of Yoania its reproductive success is not severely reduced when infested with C. vittata, whereas the robust stems of Gastrodia elata, which is its main host plant in Japan, are thought to be a defence against infestation by C. vittata., Kenji SUETSUGU., and Obsahuje bibliografii
Orchid seeds are some of the smallest in the world, and they contain only an undifferentiated embryo. When germinating, they produce an absolutely unique structure called protocorm. This structure is unable to individually obtain all compounds which are necessary for its growth. In nature, specific symbiotic fungi help young orchids to grow. Under artificial conditions, fungi are usually substituted by nutritive medium in laboratory in vitro cultures. and Jan Ponert.
This was the theme of the 4th International Congress on Orchid Conservation that took place in Hluboká nad Vltavou from May 2009 - June 6, 2011. Organisers noted "we are now experiencing dramatic changes in most aspects of your life. Modern technologies are being devised and deployed with increasing frequency; and although they make your lives easier, their consequences, such as air, soil and water, pollution greatly increase the pressure on your already over-stressed environment. To keep up with a rapidly growing human population, agricultural practices tend to be more and more intensive, which in turn has a negative effect on biodiversity in agricultural landscapes." and Pavel Kindlmann.
Sklenobýl bezlistý (Epipogium aphyllum) patří mezi nejvzácnější druhy naší flóry. Roste v bučinách a jehličnatých lesích s humózní půdou, často na lesních prameništích. Ještě donedávna byl v Čechách hodnocen jako nezvěstný. V r. 2006 se ale podařilo objevit několik malých lokalit na Šumavském Boubíně, poté v r. 2008 i jedna lokalita v Krkonoších. V červnu r. 2013 v náplavech Jizery a hned u cesty nedaleko Kořenova se podařilo objevit další dvě mikrolokality tohoto ohroženého druhu. Bylo by velmi povzbuzující domnívat se, že nárůst počtu lokalit nejen sklenobýlu, ale i jiných ohrožených druhů indikuje zlepšující se stav prostředí., Epipogium aphyllum is one of the rarest plant species of the Czech flora. It grows in humus-rich soil in beech and spruce forests, often in the vicinity of forest springs. The species has been considered missing in Bohemia until recent discoveries of a few sites in Boubín in the Šumava Mts. (Bohemian Forest, 2006) and in the Krkonoše Mts. (Giant Mts., 2008). Two new populations were found in the Giant Mts. in June 2013 - in alluvial deposits of the Jizera river and along the forest road close to the Kořenov village., and Pavla Čížková, Kamila Lencová, Pavel Hubený.
Během několika uplynulých tisíciletí byla Malta – středozemní souostroví se dvěma velkými a osídlenými ostrovy Malta a Gozo – zcela zbavena lesních porostů s převládajícími borovicí halebskou (Pinus halepensis) a dubem cesmínovitým (Quercus ilex). Současná planě rostoucí vegetace, tvořená převážně degradovanou macchií a formacemi garrigue a frygana, je nyní soustavně potlačována šířícími se sídlišti. Nicméně stojí za to navštívit Maltu a seznámit se s její květenou vyšších rostlin, čítající kolem jednoho tisíce druhů (včetně 36 zajímavých orchidejí), a to zejména v časně jarním období., Malta, a Mediterranean archipelago with two large, inhabited islands, has over the past millennia been totally deprived of forests with dominating Allepo Pine (Pinus halepensis) and Holm Oak (Quercus ilex). The contemporary wild vegetation – mainly of degraded macchia, garrigue and phrygana is being continuously suppressed by urban explosion. Nevertheless, the Maltese wild flora numbering around 1,000 vascular plant species (including 36 interesting orchids) makes a visit to Malta worthwhile, particularly in the early springtime., and Jan Čeřovský.