We studied the photosynthetic performance of sterile and fertile sporophytes in a natural population of the fern Dryopteris affinis growing within a riparian forest (Central Italy) using chlorophyll (Chl) a fluorescence transients, the OJIP phase, where O is for the minimum fluorescence, P is for the peak (the maximum), and J and I are inflections. The “vitality” of the samples was assessed by the maximum quantum yield of primary photochemistry obtained indirectly from the fluorescence data (Fv/Fm); in the same way, the so-called performance index (PIABS) was obtained from fluorescence data. The photosynthetic performance (inferred from PIABS) of D. affinis changed significantly with the seasonal development of the fronds. The highest photosynthetic performance was recorded in the summer, corresponding to the period of spore release. The photosynthetic performance decreased in the winter, down to the minimal values of senescent fronds reached at the end of the seasonal cycle (May-June). On the whole, during the seasonal development, sterile and fertile fronds had a similar photosynthetic behaviour, as inferred from fluorescence data. At the end of spore maturation and dispersal (September-October), the fertile fronds showed somewhat lower photosynthetic performance than the sterile fronds, as revealed by PIABS. Being a long-lived fern, confined to humid and undisturbed sites in the Mediterranean, D. affinis deserves to be further investigated as a potential indicator of ecological continuity in Mediterranean riparian forests., L. Paoli, M. Landi., and Obsahuje bibliografii
RNA gel hybridization showed that the expression of monodehydroascorbate reductase (MDHAR) in the wild type (WT) tomato was decreased firstly and then increased under salt- and polyethylene glycol (PEG)-induced osmotic stress, and the maximum level was observed after treatment for 12 h. WT, sense transgenic and antisense transgenic tomato plants were used to analyze the antioxidative ability to cope with osmotic stresses. After salt stress, the fresh mass (FM) and height of sense transgenic lines were greater than those of antisense lines and WT plants. Under salt and PEG treatments, sense transgenic plants showed a lower level of hydrogen peroxide (H2O2) and malondialdehyde (MDA), a higher net photosynthetic rate (PN), and the maximal photochemical efficiency of PSII (Fv/Fm) compared with WT and antisense transgenic plants. Moreover, sense lines maintained higher ascorbate peroxidase (APX) activity than WT and antisense plants under salt- and PEG-induced osmotic stress. These results indicate that chloroplastic MDHAR plays an important role in alleviating photoinhibition of PSII by elevating ascorbate (AsA) level under salt- and PEG-induced osmotic stress., F. Li ... [et al.]., and Obsahuje bibliografii
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.
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.
This article refers to the rich vegetation on the rocky slopes along the Achensee (Tyrol, Northern calcareous Alps, Karwendelalpen) described by Professor Anton Kerner 150 years ago. The vegetation today is much less diverse, the subalpine species abundant in the last centuries are absent while the species of mixed mountainous forest prevail. The abundance of the Heather (Calluna vulgaris), which was not mentioned by A. Kerner, may indicate acidification due to acid rain. And the retreat of subalpine species may indicate the on going change to a warmer climate. and Jarmila Kubíková.
A large outbreak of haemolytic uraemic syndrome and bloody diarrhoea caused by the pathogenic E. coli strain in Germany in 2011 has increased attention to foodborne diseases – bacterial infections linked to the consumption of fresh produce. Since the early 1990s, evidence is emerging that en - teropathogenic bacteria have the ability to grow and persist on crop plants for prolonged periods of time, including until harvest, and to be the carrier of illness. and Václav Kůdela.
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
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