Leaf gas-exchange responses to shadefleck-sunfleck and sun-cloud transitions were determined for in situ Cycas micronesica K.D. Hill plants on the island of Guam to add cycads to the published gymnosperm data. Sequential sunfleck-shadefleck transitions indicated understory leaves primed rapidly but open field leaves primed slowly. Time needed to reach 90% induction of net CO2 assimilation (PN) was 2.9 min for understory leaves and 13.9 min for open field leaves. Leaf responses to sun-cloud transitions exhibited minimal adjustment of stomatal conductance, so PN rapidly returned to precloud values following cloud-sun transitions. Results indicate bi-directional leaf acclimation behavior enables mature C. micronesica trees to thrive in deep understory conditions in some habitats and as emergent canopy trees in other habitats. These data are the first nonconifer gymnosperm data; the speed of gas-exchange responses to rapid light transitions was similar to some of the most rapid angiosperm species described in the literature., T. E. Marler., and Obsahuje bibliografii
A hydroponic experiment was conducted to investigate bioaccumulation and photosynthetic activity response to Cd in sweet sorghum seedlings. The seedlings were treated with 0, 50, and 100 μM Cd for 15 d. Our results showed that morphological characteristics of sweet sorghum were significantly affected by Cd treatments. The Cd concentrations in roots and shoots increased with increasing Cd concentrations in the nutrition solution; higher Cd accumulation was observed in the roots. Meanwhile, the photosynthetic activity decreased significantly and a shape of chlorophyll (Chl) a fluorescence transient in leaves was altered by Cd treatments. The Chl contents in the leaves decreased significantly, which was demonstrated by a change of spectral reflectance. Our data indicated that the higher Cd concentration reduced Chl contents and inhibited electron transport in the leaves, leading to the decrease of photosynthetic activity., Z. C. Xue, J. H. Li, D. S. Li, S. Z. Li, C. D. Jiang, L. A. Liu, S. Y. Wang, W. J. Kang., and Obsahuje bibliografii
This paper examines the changes in the species composition of aphids living in dry calcareous grasslands in Central Europe over a 25-year period. To the best of our knowledge, this is the first analysis of this type in the world that takes into account both previous and current data on species richness as well as groups of aphids that are distinguishable on the basis of biological and ecological criteria such as host-alternation and feeding types, life cycle, ecological niche, symbiosis with ants and their ecological functional groups. Over the period of more than 25 years, there has been a significant decrease in aphid α-diversity, from 171 to 105 species. The gain, which is in species not previously recorded, was 17 taxa. The loss of biodiversity occurred despite the fact that these habitats are protected and are valuable regional biodiversity hotspots. The losses are mostly related to intensive human activity in adjacent areas, which, unfortunately, has resulted in the isolation of these small, protected environmental islands by the removal of ecological corridors. Since, as is shown in this study, the frequencies between individual biological and ecological groups of aphids have been retained, it would be possible to restrict this loss of biodiversity if appropriate actions are taken., Barbara Osiadacz, Roman Hałaj, Damian Chmura., and Obsahuje bibliografii
Kudlanka nábožná (Mantis religiosa) je příklad teplomilného druhu, který v posledních letech začal expandovat i do severnějších oblastí Evropy. Na základě studia mitochondriálních markerů se ukázalo, že v rámci Evropy kudlanky náleží do tří odlišných genetických linií. Tyto linie (západoevropská, středoevropská a východoevropská) se postupně po poslední době ledové šířily na sever z různých glaciálních refugií. Tuto teorii také podporují paleoklimatická data a distribuční modely možného šíření kudlanek po poslední době ledové., The Praying Mantis (Mantis religiosa) is an example of a thermophilic species, which has recently been expanding northwards across Europe. Based on the study of mitochondrial genes, it has been shown, that the European M. religiosa belong to three different genetic lineages (West-, Central- and East-European). These lineages have been gradually spreading northwards from different glacial refugias after the last glacial period. This theory has also been supported using paleoclimatic data and distribution models of the potential spread of M. religiosa after the last glacial period., and Jakub Vitáček, Petr Janšta.
Duponchelia fovealis Zeller is a polyphagous insect that has been recently reported attacking strawberry plants (Fragaria x ananassa Duchesne). Despite its economic importance there are few studies on this pest because it is difficult to rear it in the laboratory. With a constant supply of insects, studies on alternative methods of pest control can be conducted. This study aimed at developing an artificial diet for rearing D. fovealis with biological characteristics similar to those reared on their natural diet. This study was carried out in a climate-controlled room (25°C ± 2°C, RH 70% ± 10%, and 14L : 10D). The natural diet consisted of 'San Andreas' strawberry leaves (D1), while the artificial diet (D2) was developed in which beans, casein, soy protein, yeast and wheat germ are used as sources of protein. Five instars were identified. D. fovealis completed its life cycle in 38 and 40 days when fed D1 and D2, respectively. Survival was highest for the larvae fed the artificial diet. Females fed D1 lay a mean of 300.2 ± 62.3 eggs, while those fed D2, 220.3 ± 41.8 eggs. The artificial diet is suitable for the continuous rearing of D. fovealis in the laboratory., Maria A. C. Zawadneak, Rodrimar B. Gonçalves, Alex S. Poltronieri, Bráulio Santos, Adélia M. Bischoff, Aline M. Borba, Ida C. Pimentel., and Obsahuje bibliografii
Severoameričtí raci (např. rak pruhovaný a rak signální vyskytující se i v ČR) jsou příkladem invazních živočichů, jejichž invazní potenciál je zesílen přenosem onemocnění nebezpečného pro příbuzné druhy z jiných geografických oblastí. Původcem nemoci, tzv. račího moru, je Aphanomyces astaci ze skupiny Oomycetes způsobující úhyny celých populací evropských raků. Račí mor se v Evropě vyskytuje už od 19. století a i v současnosti zůstává přes intenzívní výzkum jedním z nejvýznamnějších faktorů ohrožujících původní raky (u nás jde o raka říčního a raka kamenáče, u nichž bylo jen od roku 2004 zaznamenáno deset případů zdecimování populací touto nemocí)., North American crayfish species such as the Spiny-cheek Crayfish and the Signal Crayfish are examples of invasive animals with an ability to carry and transmit a disease lethal to their relatives from other parts of the world. The disease called the crayfish plague and caused by Aphanomyces astaci (Oomycetes) may eradicate whole populations of the indigenous European crayfish. The disease is known in Europe from the 19th century and despite intensive research it is still one of the main factors endangering indigenous crayfish., and Eva Kozubíková-Balcarová.
Ačkoli bylo světélkování u hub doloženo již ve starověku, intenzivnějšího vědeckého studia se tomuto jevu dostává teprve v posledních letech. Článek shrnuje naše dosavadní poznání bioluminiscence u hub z hlediska evolučního, ekologického i fyziologického. Jeho součástí jsou i fotografie dvou tropických druhů se světélkujícími plodnicemi - Mycena chlorophos a Filoboletus manipularis., Bioluminescence in fungi was first observed in the Archaic period or earlier, but it has only recently been studied scientifically. This paper sums up our knowledge on this phenomenon from evolutionary, ecological, and physiological points of view. Included are photos of two tropical species with luminescent fruiting bodies - Mycena chlorophos and Filoboletus manipularis., and Michal Sochor, Zuzana Egertová.
Globally, water deficit is one of the major constraints in chickpea (Cicer arietinum L.) production due to substantial reduction in photosynthesis. Photorespiration often enhances under stress thereby protecting the photosynthetic apparatus from photoinhibition. Application of bioregulators is an alternative to counter adverse effects of water stress. Thus, in order to analyze the role of bioregulators in protecting the photosynthetic machinery under water stress, we performed an experiment with two contrasting chickpea varieties, i.e., Pusa 362 (Desi type) and Pusa 1108 (Kabuli type). Water deficit stress was imposed at the vegetative stage by withholding water. Just prior to exposure to water stress, plants were pretreated with thiourea (1,000 mg L-1), benzyladenine (40 mg L-1), and thidiazuron (10 mg L-1). Imposed water deficit decreased relative water content (RWC), photosynthetic rate (P N), quantum efficiency of PSII (Fv/Fm), and enhanced lipid peroxidation (LPO). However, bioregulator application maintained higher RWC, P N, Fv/Fm, and lowered LPO under water stress. Expression of Rubisco large subunit gene (RbcL) was low under water stress both in the Kabuli and Desi type. However, bioregulators strongly induced its expression. Although poor expression of two important photorespiratory genes, i.e., glycolate oxidase and glycine decarboxylase H subunit, was observed in Desi chickpea under imposed stress, bioregulators in general and cytokinins in particular strongly induced their expression. This depicts that the application of bioregulators protected the photosynthetic machinery by inducing the expression of RbcL and photorespiratory genes during water deficit stress., T. V. Vineeth, P. Kumar, G. K. Krishna., and Obsahuje seznam literatury