V této práci sumarizujeme data o výskytu invazních druhů řas a sinic v České republice a mapujeme reálná či potenciální rizika jejich rozšíření. Seznam invazních druhů v ČR obsahuje 10 druhů sinic, 9 rozsivek, 1 obrněnku, 1 zástupce třídy Ulvophyceae, 2 zelené řasy třídy Chlorophyceae a jednu krásivku., This paper summarizes data on alien species of algae and cyanobacteria in the Czech Republic; we identified actual or potential risks resulting from their spread. The list of aliens contains 10 species of Cyanobacteria (Cyanophyta), 10 species of Bacillariophyceae, one species of Dinophyta, one species of Ulvophyceae, two species of Chlorophyceae, and one species of Desmidiales., and Jan Kaštovský ... [et al.].
Vřeckovýtrusná houba druhu Hymenoscyphus pseudoalbidus s anamorfou Chalara fraxinea způsobuje onemocnění známé jako nekróza jasanu na různých druzích jasanů v Evropě. Onemocnění se objevilo v Polsku na počátku 90. let po introdukci patogenu z Východní Asie. Následně se epidemie rozšířila do celého areálu přirozeného rozšíření hostitelských druhů a zasáhla i umělé výsadby a školky. Článek shrnuje historii a současný stav našeho poznání od objevu patogenu až po nejnovější poznatky., The ascomycete Hymenoscyphus pseudoalbidus with its anamorph Chalara fraxinea causes a disease known as ash dieback on various ash (Fraxinus) species in Europe. The disease emerged in Poland in the early 1990s after introduction of the pathogen from East Asia. The epidemic spread across the entire native distribution range of the host trees also affected artificial plantations and nurseries. This review presents the history and the state of research from the discovery of the pathogen to the most recent findings., and Ondřej Koukol, Ludmila Havrdová.
Ačkoli jsou elektrické signály typičtější pro neurony živočichů, také rostliny jsou schopné vytvářet tento druh signálů. Rozeznáváme u nich dva základní typy - variační a akční potenciály. Ty se od sebe odlišují určitými vlastnostmi, ale oba typy mají významný dopad na fyziologické procesy v rostlinách, např. na pohyb listů, fotosyntézu, dýchání, opylování, zavírání průduchů, syntézu hormonů nebo trávení hmyzu u masožravých rostlin., Although electrical signals are more typical for animal neurons, plants also have the ability to generate these signals. Two different types are recognized: action and variation potentials. They differ in certain characteristics, however both have significant impact on physiological processes in plants; e.g. on leaf movement, photosynthesis, respiration, pollination, stomata closure, hormone synthesis and insect digestion in carnivorous plants., Andrej Pavlovič., and Obsahuje seznam literatury
Giant rosettes are ones of the most striking features of the vegetation in the high tropical Andes, with Coespeletia moritziana reaching the highest altitudes up to 4,600 m a.s.l. Different from other giant rosettes, this species grows on rock outcrops with poorly developed soils and where water availability may be limited. Two questions are addressed in this study: How does this species respond in terms of water relations to maintain favorable gas-exchange conditions? Considering that adult plants rely on a water-reserving central pith, how do early stages respond to this environment’s extreme conditions? Water relations and gas-exchange studies were carried out on juveniles, intermediate and adult C. moritziana plants during wet and dry seasons in Páramo de Piedras Blancas at 4,200 m a.s.l. Adult plants maintained higher leaf water potentials (ΨL) during the wet season, however, no differences between stages were found for the dry season. Minimum dry season ΨL were never near the turgor loss point in any of the stages. Juveniles show a more strict stomatal control during the dry season to maintain a favorable water status. Net photosynthesis significantly decreased in intermediate and juvenile stages from wet to dry seasons. Our results suggest that
C. moritziana resists more extreme conditions compared to other Andean giant rosettes., F. Rada, A. Azócar, A. Rojas-Altuve., and Obsahuje bibliografii
Effects of water and nitrogen (N) supply on growth and photosynthetic response of B. carinata were examined in this study. Plant growth and related characteristics varied significantly in response to the availability of water and nitrogen. B. carinata maximized the utilization efficiency of the most limiting resources by developing physiological adaptations, such as changes in root and leaf development. The utilization of water and N was tightly linked with the availability of each resource. Instantaneous water-use efficiency (WUE) was always greater in plants with high-N nutrition [50, 100, and 150 kg(N) ha-1] than in the low-N-treated plants
[0 kg(N) ha-1] in all watering treatments. Instantaneous N-use efficiency (PNUE) decreased significantly with increasing water stress in all N treatments. Seed yield is significantly related to PNUE (p>0.05) but not WUE (p<0.05). The positive relationship between leaf net photosynthetic rate (PN) and seed yield suggests that PN can be used as an important tool for selection of new strains with high seed yield. and X. Pan ... [et al.].
Environmental conditions that promote photorespiration are considered to be a major driving force for the evolution of C4 species from C3 ancestors. The genus Flaveria contains C3 and C4 species as well as a variety of intermediate species. In this study, we compare the water-use efficiency of intermediate Flaveria species to that of C3 and C4 species. The results indicate that under both well-watered and a drought-stress condition, C3-C4 and C4-like intermediacy in Flaveria species improve water-use efficiency as compared to C3 species. and M. C. Dias, W. Brüggemann.
The coffee plant is native to shaded environments and its seedlings are often produced in shaded nurseries. However, some nursery managers, in an effort to improve the acclimation of seedlings to field conditions after transplantation, produce seedlings in full sun exposure. In this study, the morphological and physiological parameters of arabica coffee (Coffea arabica) seedlings produced in full sun (T1) and in shade (T2) were examined. The biomass accumulation and relative growth rate of T1 and T2 seedlings were similar. The T1 seedlings had less biomass allocation to shoots, a lower leaf mass ratio and a lower leaf area ratio; however, they had a greater net assimilation rate (rate of increase in plant mass per unit leaf area), which was associated with a greater net photosynthetic rate. There were no alterations in the concentrations of total chlorophylls or in the chlorophyll a/b ratio when comparing T1 and T2 seedlings. No indications of photoinhibition or photooxidative damage were observed in the T1 plants, which were shown to have a more robust antioxidant system than the T2 plants. Seedlings transferred from shade to full sun (T3) were not capable of utilising the incident extra light to fix CO2. These seedlings showed a remarkable nocturnal retention of zeaxanthin and a significantly increased deepoxidation state of the xanthophyll cycle, even at predawn, but the activity of antioxidant enzymes was lower than in the T1 and T2 plants. Despite the acclimation capacity of T3 seedlings to the new light environment, they exhibited chronic photoinhibition and considerable photooxidative damage throughout the seven days following the transfer to full sun exposure. We further discuss the practical implications of producing coffee seedlings in full sunlight and under shade. and G. A. B. K. Moraes ... [et al.].
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.
Rostlinný hormon auxin je známý jako regulátor prodlužování stonku a (ne)aktivity postranních pupenů. Ve skutečnosti ale dokáže mnohem více. Ovšem jen za předpokladu, že se ho správné množství vyskytuje ve správném místě a čase. Příjem auxinového signálu zajišťují receptory uvnitř buňky i na jejím povrchu., The plant hormone auxin is a long-known regulator of shoot elongation and auxiliary bud (in)activity. But there is much more about it – if the right amount of auxin appears at the right place and time. The auxin signal is perceived by both intracellular and surface receptors., and Jiří Libus.
Šídlatky (rod Isoëtes) jsou prastaré plavuně s pozoruhodnými adaptacemi na nedostatek živinových zdrojů ve vlastním prostředí. Jejich unikátní životní strategie je dodnes úspěšná, ne však bezmezně odolná vůči globálním změnám prostředí. Šídlatky tvoří významnou složku vyhraněných vodních i suchozemských ekosystémů a citlivě indikují jejich stav. Detailní znalost anatomie, fyziologie a ekologie těchto živoucích fosilií je klíčem k pochopení fungování a zranitelnosti jejich často rozsáhlých biotopů a zajištění jejich ochrany, případně obnovy., Quillworts (genus Isoëtes) are ancient lycophytes with remarkable adaptations to the sparse nutrient sources in their environment. Their unique life strategy has been successful to these days, but not entirely resistant to the global environmental changes. Quillworts make up an important component in well-defined aquatic and dry-land ecosystems and sensitively indicate their state. A detailed knowledge of the anatomy, physiology and ecology of these living fossils is the key to understanding the operation and vulnerability of their often extensive biotopes and to ensuring their protection or recovery., and Martina Čtvrtlíková.