Článek stručně shrnuje základní adaptace xerotermních rostlin. K těm patří i povrchové struktury vzniklé z epidermis. Blíže je v textu pojednáno o krycích chlupech (trichomech), jejich funkci a morfologii. Článek doplňuji fotografie různých typů těchto trichomů., This article briefly summarises essential adaptations of xerothermic species. These include epidermal structures covering plant surface. The plant hairs (trichomes), their function and morphology are described in detail. The text is supplemented with photos of some trichome types., and Hana Mašková.
Tropické lesy ostrova Borneo v jihovýchodní Asii jsou celosvětově výjimečné vysokou biodiverzitou různých skupin organismů. Jejich podoba byla formována mimo jiné během čtvrtohorního kolísání hladiny světových oceánů, kdy byly ostrovy sundské oblasti vzájemně propojeny či odděleny, což mělo vliv na migraci organismů. Současná diverzita lesů Bornea sleduje gradient nadmořské výšky a vlastnosti substrátů, přičemž můžeme rozlišit několik hlavních typů lesa. V posledních desetiletích jsme svědky masivní těžby lesů, které jsou mnohde převáděny na plantáže palmy olejné., Tropical forests of the island of Borneo in South East Asia harbour an extraordinary high biodiversity of various groups of organisms. They have been shaped, among other influences, by the Quaternary fluctuations of the level of world’s oceans, connecting or dividing islands within the Sundaland, which has affected migration of species. The present diversity of forests in Borneo follows an elevational gradient and substrate properties, thus forming several main forest types. Over the past few decades, we have witnessed massive logging and transformation of forests into oil palm (Elaeis guineensis) plantations., Radim Hédl., and Obsahuje seznam literatury
Borneo je ostrovem se zajímavou geomorfologií a překvapivě různorodou geologií. Oba faktory se spolu s historickým vývojem určujícím migrace druhů podílely na současné pestrosti bornejské flóry. Pozoruhodné funkční a taxonomické skupiny rostlin najdeme nejen v zapojeném lese, ale také nad horní hranicí lesa, v pobřežních prostředích, podél vodních toků a jinde. V krátkosti jsou představeny vybrané funční skupiny epifyty, epifyly, liány, masožravé rostliny s význačným rodem láčkovka, nezelené rostliny, rheofyty a alpinské rostliny, mezi kterými nalezneme i trávy temeprátních oblastí. Z pozoruhodných taxonomických skupin představujeme zázvory, áronovité, begonie a pěnišníky, které mají na Borneu jedno z center své diverzity., Borneo is an island with conspicuous geomorphology and variable geology. Both factors have contributed, along with historical development determining species migrations, to the present richness of the flora of Borneo. Remarkable functional and taxonomic groups of herbs occur not only in closed forests, but also above the timberline, in coastal and riparian habitats, and elsewhere. Selected functional groups are briefly introduced: epiphytes, epiphylles, rheophytes, carnivorous, achlorophyllous and alpine plants. From conspicuous taxonomic groups, we introduce gingers, aroids, begonias and rhododendrons., and Martin Dančák ... [et al.].
Tropické deštné lesy jihovýchodní Asie jsou známé vysokou druhovou i morfologickou diverzitou rostlin a stromy jsou logicky klíčovou složkou tohoto ekosystému. Ostrov Borneo, se svými přibližně 3 000 druhy dřevin, není v tomto ohledu žádnou výjimkou. Determinace druhů je zde právě kvůli vysoké diverzitě mimořádně složitým a komplexním úkolem, který vyžaduje mnohem větší úsilí než při práci v temperátních ekosystémech. Kromě běžných znaků se při určování tropických dřevin využívají i speciální znaky, jako je např. zásek do borky, barva exudátu či charakteristická vůně. Článek v krátkosti představuje jak významné stromové dominanty deštných lesů Bornea, jako jsou dvoukřídláčovité, tak i další čeledi stromů, jejichž zástupci jsou v lesích bohatě zastoupeni. Zajímavý je také výskyt evolučně starých linií, které nesou primitivní znaky krytosemenných rostlin. Tento článek uzavírá čtyřdílný seriál o tropických lesích Bornea., The tropical rain forests of south-east Asia are famous for their tall plant species and morphological diversity, with trees forming a key component of this ecosystem. The island of Borneo with more than 3,000 species of woody plants is no exception. Due to this high diversity, species identification is a very demanding and complex task, especially in comparison with temperate ecosystems. Apart from traditional characteristics, special traits are also useful for identification, e.g. bark slash and the resulting colour of exudate or typical odour. This article concludes the four-part series and presents a brief overview of dominant tree families of the tropical forests of Borneo including Dipterocarpaceae. The remarkable ancient evolutionary lineages are also introduced., and Michal Hroneš, Radim Hédl, Martin Dančák.
Characterization of different component processes of photosynthesis is useful to understand the growth status of plants and to discover possible unintended effects of genetic modification on photosynthesis in transgenic plants. We focused on the changes in photosynthetic gas-exchange properties, reflectance spectra, and plant growth traits among groups of different transgenic barley T1 (TolT1) and its isogenic controls (TolNT1), TolT1, and group of its own transgenic progenies T2 (TolT2), TolNT1 and its wild type (WT), respectively. Gas-exchange measurements showed that only the net photosynthetic rate (P N) and the light-use efficiency (LUE) differed significantly between TolT1 and TolT2 with no obvious changes of other characteristics. Reflectance measurements indicated that the reflectance ratio was sensitive to identify the differences between two barley groups. Differences in reflectance expressed on an index basis depended on barley groups. The relationship between LUE and the photochemical reflectance index (PRI) at a leaf level among different barley groups of WT, TolNT1, TolT1 and TolT2 did not changed obviously. The differences in the total leaf area per plant (LA) between WT and TolNT1 as well as between TolT1 and TolT2 were significant. This study finally provided a plausible complex explanation for the unintended effects of genetic transformation on photosynthesis-related properties in barley at different levels. Furthermore, it was concluded that the photosynthesis-related properties of transgenic plants based on gas exchange, leaf reflectance, and plant growth measurements responded to the same environment in a more different way between two subsequent generations than to the processes of the gene insertion by Agrobacterium and associated tissue culture., C. X. Sun ... [et al. ]., and Obsahuje bibliografii
In three separate experiments, the effectiveness of a SPAD-502 portable chlorophyll (Chl) meter was evaluated for estimating Chl content in leaves of Eugenia uniflora seedlings in different light environments and subjected to soil flooding. In the first experiment, plants were grown in partial or full sunlight. In the second experiment plants were grown in full sunlight for six months and then transferred to partial sunlight or kept in full sunlight. In the third experiment plants were grown in a shade house (40% of full sunlight) for six months and then transferred to partial shade (25-30% of full sunlight) or full sunlight. In each experiment, plants in each light environment were either flooded or not flooded. Non-linear regression models were used to relate SPAD values to leaf Chl content using a combination of the data obtained from all three experiments. There were no significant effects of flooding treatments or interactions between light and flooding treatments on any variable analyzed. Light environment significantly affected SPAD values, chlorophyll a (Chl a), chlorophyll b (Chl b), and total chlorophyll [Chl (a+b)] contents in Experiment I (p≤0.01) and Experiment III (p≤0.05). The relationships between SPAD values and Chl contents were very similar among the three experiments and did not appear to be influenced by light or flooding treatments. There were high positive exponential relationships between SPAD values and Chl (a+b), Chl a, and Chl b contents. and M. S. Mielke, B. Schaffer, C. Li.
One broad-leaved pioneer tree, Alnus formosana, two broad-leaved understory shrubs, Ardisia crenata and Ardisia cornudentata, and four ferns with different light adaptation capabilities (ranked from high to low, Pyrrosia lingus, Asplenium antiquum, Diplazium donianum, Archangiopteris somai) were used to elucidate the light responses of photosynthetic rate and electron transport rate (ETR). Pot-grown materials received up to 3 levels of light intensity, i.e., 100%, 50% and 10% sunlight. Both gas exchange and chlorophyll (Chl) fluorescence were measured simultaneously by an equipment under constant temperature and 7 levels (0-2,000 μmol m-2 s-1) of photosynthetic photon flux density (PPFD). Plants adapted to-or acclimated to high light always had higher
light-saturation point and maximal photosynthetic rate. Even materials had a broad range of photosynthetic capacity [maximal photosynthetic rate ranging from 2 to 23 μmol(CO2) m-2 s-1], the ratio of ETR to gross photosynthetic rate (PG) was close for A. formosana and the 4 fern species when measured under constant temperature, but the PPFD varied. In addition, P. lingus and A. formosana grown under 100% sunlight and measured at different seasonal temperatures (15, 20, 25, and 30°C) showed increased ETR/P G ratio with increasing temperature and could be fitted by first- and second-order equations, respectively. With this equation, estimated and measured PG were closely correlated (r2 = 0.916 and r2 = 0.964 for P. lingus and A. formosana, respectively, p<0.001). These equations contain only the 2 easily obtained dynamic indicators, ETR and leaf temperature. Therefore, for some species with near ETR/PG ratio in differential levels of PPFD, these equations could be used to simulate dynamic variation of leaf scale photosynthetic rate under different temperature and PPFD conditions., S.-L.. Wong ... [et al.]., and Obsahuje bibliografii
Some reports indicate that mesophyll conductance (gm) to carbon dioxide varies greatly with the substomatal carbon dioxide concentration (Ci) during the measurement, while other reports indicate little or no change in g m with Ci. I used the oxygen sensitivity of photosynthesis to determine the response of gm to Ci over the range of about 100 to 300 μmol mol-1 Ci at constant temperature in common bean (Phaseolus vulgaris) and soybean (Glycine max) grown over a range of temperatures and photosynthetic photon flux densities (PPFD). In soybean grown and measured at high PPFD there was only a slight, approximately 15% decrease in gm with Ci over the range of 100 to 300 μmol mol-1. With lower PPFD during the measurement of gm, and especially with low PPFD during plant growth, there was a larger decrease in gm with Ci in soybean. In common bean, the same range in Ci resulted in about a 60% decrease in g m for plants grown and measured at high PPFD, with an even larger decrease for plants at low growth or measurement PPFD. Growth temperatures of 20 to 30°C had little influence on the response of gm to Ci or its absolute value in either species. It is concluded that these two species differed substantially in the sensitivity of gm to Ci, and that PPFD but not temperature during leaf development strongly affected the response of gm to Ci. and J. A. Bunce.