The altitudinal effects on photosynthesis were measured on progenies of three populations of Rosa platyacantha Schrenk from altitudes of 1,170 (L); 1,580 (M); and 1,920 (H) m a. s. l. During the day, net photosynthetic rate (PN) decreased in all populations due to the high air temperature in the summer. The H population showed a significantly lower PN at noon compared to other populations. The midday depression of PN occurred in L and M populations due to stomatal limitations, while PN inhibition was associated with PSII activity decline in the H population. In order to avoid photodamage, the plants of H population triggered active antioxidant defenses with a higher enzyme activity and redox ratio of ascorbate at midday compared to the L and M populations. However, more oxidative injury still occurred in the H plants at noon due to higher lipid peroxidation. Our results indicated that the provenance significantly affected photosynthesis in R. platyacantha from northwestern China., S. H. Yang, J. J. Wei, H. Ge., and Obsahuje bibliografii
Photoinhibition is a significant constraint for improvement of radiation-use efficiency and yield potential in cereal crops. In this work, attached fully expanded leaves of seedlings were used to assay the factors determining photoinhibition and for evaluation of tolerance to photoinhibition in wheat (Triticum aestivum L.). Our results showed that even 1 h under PPFD of 600 µmol(photon) m-2 s-1 could significantly reduce maximal quantum yield of PSII photochemistry (Fv/Fm) and performance index (PI) compared to low light [300 µmol(photon) m-2 s-1]. The decrease of Fv/Fm and PI was more noticeable with the increase of light intensity; irradiance higher than 800 µmol(photon) m-2 s-1 resulted in photoinhibition. Compared to 25°C, lower (20°C) or higher temperature (≥ 35°C) aggravated photoinhibition, while slightly high temperature (28°) alleviated photoinhibition. At 25°C, irradiance of 1,000 µmol(photon) m-2 s-1 for 1 h was enough to cause photoinhibition and a significant decrease of Fv/Fm, PI, trapped energy flux, electron transport flux, and density of reaction center as well as increase of dissipated energy flux per cross section were observed. In addition, seedlings at 21-32 days after planting showed a relatively stable phenotype, while the younger or older seedlings indicated an increased susceptibility to photoinhibition, especially in senescing leaves. Finally, six wheat varieties with relative tolerance to photoinhibition were identified from 22 Chinese winter wheat varieties by exposing attached leaves of the 25-d old seedlings for 1 h to 1,000 µmol(photon) m-2 s-1 at 25°C. Therefore, our work established a possible method for development of new wheat varieties with enhanced tolerance to photoinhibition., H. Li, Q. Zheng, J. Zhang, B. Li, Z. Li., and Obsahuje bibliografii
When insect herbivores develop over many generations on the same plant species, their descendants may evolve physiological adaptations that enable them to develop more successfully on that plant species than naïve conspecifics. Here, we compared development of wild and lab-reared caterpillars of the cabbage moth, Mamestra brassicae, on a cultivar of cabbage Brassica oleracea (cv. Cyrus) and on a wild plant species, sorrel, Rumex acetosa, on which the wild strain had been collected and reared for two earlier consecutive generations. The lab strain had been reared on the same cabbage cultivar for more than 20 years representing > 200 generations. Survival to adult did not vary with strain or plant species. Both strains, however, developed significantly faster when reared on R. acetosa than B. oleracea. Pupae from the field strain were larger when reared on B. oleracea than on R. acetosa, whereas the identity of the plant species did not matter for the lab strain. Our results show that long-term rearing history on cabbage had little or no effect on M. brassicae performance, suggesting that some generalist herbivores can readily exploit novel plants that may be chemically very different from those on which they have long been intimately associated., Jeffrey A. Harvey, Eke Hengeveld, Miriama Malcicka., and Obsahuje bibliografii
The chiggers (Acari: Trombiculidae) Blankaartia sinnamaryi (Floch et Fauran, 1956), Parasecia soucouyanti (Brennan et Yunker, 1966), Eutrombicula lipovskyana (Wolfenbarger, 1952) and Neoschoengastia dalmati Brennan, 1951 were found in Honduras on a total of twelve bird species. Parasecia soucouyanti was recorded parasitising birds for the first time. All these mites are here reported from Honduras for the first time., Stanislav Kalúz, Ivan Literák, Stanislav Kolenčík., and Obsahuje bibliografii
We identified and characterised the deep red state (DRS), an optically-absorbing charge transfer state of PSII, which lies at lower energy than P680, in the red algae Cyanidioschyzon merolae by means of low temperature absorption and magnetic circular dichroism spectroscopies. The photoactive DRS has been previously studied in PSII of the higher plant Spinacia oleracea, and in the cyanobacterium Thermosynechococcus vulcanus. We found the DRS in PSII of C. merolae has similar spectral properties. Treatment of PSII with dithionite leads to reduction of cytochrome (cyt) b559 and the PsbV-based cyt c550 as well as the disassembly of the oxygen-evolving complex. Whereas the overall visible absorption spectrum of PSII was little affected, the DRS absorption in the reduced sample was no longer seen. This bleaching of the DRS is discussed in terms of a corresponding lack of a DRS feature in D1D2/cyt b559 reaction centre preparations of PSII., J. Langley, J. Morton, R. Purchase, L. Tian, L. Shen, G. Han, J.-R. Shen, E. Krausz., and Obsahuje bibliografické odkazy
Food webs are of crucial importance for understanding any ecosystem. The accuracy of food web and ecosystem models rests on the reliability of the information on the feeding habits of the species involved. Water boatmen (Corixoidea) is the most diverse superfamily of water bugs (Heteroptera: Nepomorpha), frequently the most abundant group of insects in a variety of freshwater habitats worldwide. In spite of their high biomass, the importance of water boatmen in aquatic ecosystems is frequently underestimated. The diet and feeding habits of Corixoidea are unclear as published data are frequently contradictory. We summarise information on the feeding habits of this taxon, which exemplify the difficulties in evaluating published data on feeding habits in an invertebrate taxon. It is concluded that Corixoidea are, unlike other true bugs, capable of digesting solid food, but their feeding habits are still insufficiently known. The dominant feeding strategy in this taxon is zoophagy, but several species consume other foods, particularly algae and detritus. Only members of the subfamily Cymatiainae seem to be exclusively predators. In other subfamilies, the diet of different species and different sexes or populations of a single species may vary depending on the food available or is still unknown. We conclude, that a multi-method approach is needed to elucidate the feeding habits of aquatic insects and invertebrates in general., Christian W. Hädicke, Dávid Rédei, Petr Kment., and Obsahuje bibliografii
Honey bees are not only important for honey production but also as pollinators of wild and cultivated plants. The Eastern honeybee (Apis cerana) is more resistant to several pathogens than the Western honeybee (Apis mellifera), and the genomes of two strains of the nominotypical subspecies, A. cerana cerana, northern (Korea) and southern (China) strains, have been sequenced. Apis cerana japonica, another subspecies of A. cerana, shows many specific features (e.g. mildness, low honey production and frequently absconds) and it is important to study the molecular biological and genetic aspects of these features. To accelerate the genetic research on A. cerana japonica, we sequenced the genome of this subspecies. The draft genome sequence of A. cerana japonica presented here is of high quality in terms of basic genome status (e.g. N50 is 180 kbp, total length is 211 Mbp, and largest contig length is 1.31 Mbp) and BUSCO results. The gene set of A. cerana japonica was predicted using AUGUSTUS software and the set of genes was annotated using Blastp and InterProScan, and GO terms were added to each gene. The number of genes is higher than in A. mellifera and in the two strains of A. cerana cerana sequenced previously. A small number of transposable elements and repetitive regions were found in A. cerana japonica, which are also in the genomes of A. mellifera and the northern and southern strains of A. cerana cerana. Apis cerana is resistant to several pathogens that seriously damage A. mellifera. We searched for 41 orthologs related to the IMD and Toll pathways, which have key roles in the immune reaction to invading pathogens. Some orthologs were not identified in the genome of the northern strain of A. cerana cerana. This indicates that the Toll and IMD pathways function in the same way as in A. mellifera and Drosophila melanogaster., Kakeru Yokoi, Hironobu Uchiyama, Takeshi Wakamiya, Mikio Yoshiyama, Jun-Ichi Takahashi, Tetsuro Nomura, Tsutomu Furukawa, Shunsuke Yajima, Kiyoshi Kimura., and Obsahuje bibliografii
Herbivory on liverworts is rarely reported. We studied the effects of feeding by larvae of the sciarid fly Scatopsciara cunicularius on the growth of the thalloid liverwort Marchantia polymorpha at two different constant temperatures, 12°C and 22°C. Larvae reared at the lower temperature fed slower and over a longer period of time, which resulted in more damage and a greater reduction in the growth of the liverwort than that caused by those reared at the higher temperature. The reduction in growth of the liverwort was positively density-dependent in terms of number of larvae at both temperatures. These results indicate that the larvae of S. cunicularius are likely to be an effective means of controlling M. polymorpha, which is a common weed in plant nurseries and greenhouse cultures., Weerachon Sawangproh, Johan Ekroos, Nils Cronberg., and Obsahuje bibliografii
C-type natriuretic peptides (CNP) play an inhibitory role in smooth muscle motility of the gastrointestinal tract, but the effect of CNP on delayed rectifier potassium currents is still unclear. This study was designed to investigate the effect of CNP on delayed rectifier potassium currents and its mechanism by using conventional whole-cell patch- clamp technique in guinea-pig gastric myocytes isolated by collagenase. CNP significantly inhibited delayed rectifier potassium currents [IK (V)] in dose-dependent manner, and CNP inhibited the peak current elicited by depolarized step pulse to 86.1±1.6 % (n=7, P<0.05), 78.4±2.6 % (n=10, P< 0.01) and 67.7±2.3 % (n=14, P<0.01), at concentrations of 0.01 μmol/l, 0.1 μmol/l and 1 μmol/l, respectively, at +60 mV. When the cells were preincubated with 0.1 μmol/l LY83583, a guanylate cyclase inhibitor, the 1 μmol/l CNP-induced inhibition of IK (V) was significantly impaired but when the cells were preincubated with 0.1 μmol/l zaprinast, a cGMP-sensitive phosphodiesterase inhibitor, the 0.01 μmol/l CNP-induced inhibition of IK (V) was significantly potentiated. 8-Br-cGMP, a membrane permeable cGMP analogue mimicked inhibitory effect of CNP on IK (V). CNP-induced inhibition of IK (V) was completely blocked by KT5823, an inhibitor of cGMP-dependent protein kinase (PKG). The results suggest that CNP inhibites the delayed rectifier potassium currents via cGMP-PKG signal pathway in the gastric antral circular myocytes of the guinea-pig., H. Y. Xu, X. Huang, M. Yang, J.-B. Sun, L.-H. Piao, Y. Zhang, L. Gao, W.-X. Xu., and Obsahuje bibliografii a bibliografické odkazy
The study investigated the effects of different CaCl2 concentrations (2, 5, and 10 mM) on photosynthetic enzymatic activities, photosynthesis, and chlorophyll fluorescence of tung tree seedlings under drought conditions. Plants were sprayed with either CaCl2 or distilled water until run-off. Irrigation was then withheld to induce drought stress. The strength of drought stress was evaluated by relative leaf water content and soil water content, which was 27.3 and 9.5% on day 0 and day 12, respectively. Drought stress decreased activities of ribulose-1,5-bisphosphate carboxylase/oxygenase and phosphoenolpyruvate carboxylase, chlorophyll (a+b) content, net photosynthetic rate, stomatal conductance, transpiration rate, electron transport rate, the maximal quantum yield of PSII photochemistry, and effective quantum yield of PSII in tung tree seedlings. The CaCl2 pretreatments alleviated the negative effect of drought stress to some degree on all the parameters mentioned above., Z. Li, X. F. Tan, K. Lu, Z. M. Liu, L. L. Wu., and Obsahuje bibliografii