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61.
A methodology is proposed for assessing the ecological value of streams in the catchment of the Moravská Dyje River. It is concluded that by using a wide range of parameters that a more objective assessment is achieved than if only one were used. The landscape of the catchment studied contains excessive amounts of nutrients and, in comparison to its natural state, has become too uniform. 相似文献
62.
R. Socha J. Šula 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1996,166(6):382-387
Three different cultures of dimorphic bug,Pyrrhocoris apterus, were analyzed concerning diapause and its relation to wing morph pattern. The proportion of macropterous bugs was considerably
higher (36%) in the Mediterranean culture from Israel than that (1.3%) in the temperate culture from the Czech Republic. The
macropterous morph- and brachypterous morphrelated types of reproduction arrest, differing by the length of pre-oviposition
period, were distinguished in cultures analyzed. The reproduction arrest with an average pre-oviposition period of 38.2 days
in Mediterranean macropters and 18.5 days in macropters from selected macropterous strain, was found to be typical for macropterous
morph. Two different photoperiodic conditions induced macropterous morph-related reproduction arrest, the long-day (18 h light-6
h dark) photoperiod in macropterous strain macropters and the short-day (12 h light-12 h dark) photoperiod in Mediterranean
macropters. The brachypterous morph-related reproduction arrest, characterized by pre-oviposition period longer than 90 days,
occurred predominantly in diapausing brachypterous bugs. While the hibernal diapause of brachypterous bugs was characterized
by a very high level of the 78- and 82-kDa proteins in haemolymph, their content in haemolymph of macropters during macropterous
morph-related reproduction arrest was almost as low as in the reproductive adults. The variation of reproduction arrest in
relation to wing dimorphism represents an important feature in the life strategy ofP. apterus. 相似文献
63.
Miodrag Petrović Ilijana Grigorov Tanja Milosavljević Desanka Bogojević Snežana Ŝekularac Ljiljana Ševaljević 《Molecular biology reports》1996,23(2):79-85
A 29 kD soluble rat liver nucleoprotein (p29) has increased binding affinity for the hormone responsive element (RE) of the rat haptoglobin (Hp) gene during the acute-phase reaction. In this work the possibility of its structural and functional homology to the high mobility group 1 (HMG1) nonhistone protein constituent of chromatin was examined. The results of two-dimensional gel electrophoresis, Southwestern and Western immunoblot analyses, showed that p29 and HMG1 are homologous protein species. On the basis of in vitro and in vivo phosphorylation/dephosphorylation experiments, we discuss the modulatory role of phosphate groups in view of the structure and function of p29. 相似文献
64.
M. Popović S. KevreŠan J. Kandrač J. Nikolić N. Petrović R. Kastori 《Biologia Plantarum》1996,38(2):281-287
In young sugar beet plants cadmium suppressed the activity of nitrate reductase, glutamine synthetase and glutamate dehydrogenase,
whereas sulphur exhibited a protective role towards activity of these enzymes, except of glutamine synthetase. Protein synthesis
was suppressed in the absence of S in nutrient medium; the lowest level was at 10-3 M Cd2+. Chloroplast pigment contents were increased by S while Cd2+, even in the lowest concentration, (10−5 M) showed a repressive effect. The highest concentrations of Cd2+ (10−3 M) caused a decrease in dry mass, whereas S induced its increase. Nitrate content was increased in the presence of
Cd2+ and decreased by increased concentration of S.
Acknowledgement: The authors acknowledge financial support of the Ministry for Science and Technology of Serbia.
The paper was presented at 9th Congress of the Federation of European Societies of Plant Physiology, Brno, Czech Republic,
3–8 July 1994. 相似文献
65.
J. PosplŠllová 《Biologia Plantarum》1996,38(4):605-609
Tobacco plantlets were grownin vitro on Murashige and Skoog’s medium with2 % of saccharose. Addition of 0.01 mM abscisic acid (ABA) into the medium decreased stomatal conductance of the adaxial epidermis and especially the abaxial epidermis without negative effects on growth parameters. As a result the rate of water loss from ABA-treated plantlets taken out of cultivation vessels was slower than that of control plantlets. This could help their acclimation after transplantation toex vitro conditions. 相似文献
66.
Morphology of pollen grains collected from healthy and virus infected plants ofChenopodium quinoa L.,Chenopodium album L. andNicotiana tabacum L. cv. Samsun was investigated using scanning electron microscopy (SEM). Pollen grains from tobacco plans infected with tobacco mosaic virus (TMV) were smaller, with rounded shape and conspicuous deformation of aperture unlike oval and smooth pollen grains from healthy plants. No morphological alterations were observed inC. quinoa andC. album plants infected with TMV and cucumber mosaic virus (CMV). Polyacrylamide gel electrophoresis of pollen proteins revealed substantial quantitative and qualitative differences in protein components of pollen grains collected from healthy and virus infected plants 相似文献
67.
Jan Nešvera Jitka Hochmannová Miroslav Pátek Alena Šroglová Věra Bečvářová 《Applied microbiology and biotechnology》1994,40(6):864-866
Gram-positive facultative methylotrophic coryneform bacterium Brevibacterium methylicum was efficiently transformed with various plasmids using electroporation of intact cells. In addition to the plasmid vectors pEC71 and pZ6-1 constructed on the basis of cryptic plasmids from coryneform bacteria, broad-host-range plasmids pLS5 (derivative of plasmid pMV158 from Streptococcus agalactiae) and RSF1010 belonging to the incompatibility group IncQ from Gram-negative bacteria were found to be present as autonomous structurally unchanged DNA molecules in B. methylicum transformants. With the exception of pZ6-1, all these plasmids were stably maintained in B. methylicum cells grown under non-selective conditions. When plasmid DNAs isolated from B. methylicum were used, the highest efficiency of transformation (105 transformants/g DNA) was achieved.
Correspondence to: J. Nevera 相似文献
68.
Hypocotyls of seedling plants of the sunflower inbred line HNK-81 were used as a source of protoplasts. Optimal conditions
of isolation and culture of protoplasts were established. Using the method of individual culture in microdrops, a 77% final
plating efficiency was achieved. Cytokinins, especially zeatin, showed a significant influence on the formation of globular
embryo-like structures, but these failed to develop into mature embryos. Calli obtained in liquid media containing auxins
and cytokinins grew on agar solidified media without growth regulators.
Communicated by M. ONDŘEJ 相似文献
69.
In comparison with the parental cv. Finale the ‘RisfixC’ supernodulator exhibited higher, continuously increasing nodule number and fresh mass accumulation, but substantially lower individual nodule fresh mass, leghemoglobin concentration, and specific acetylene reduction activity of nodule tissue. There were no substantial differences between Finale and ‘RisfixC’ in total acetylene reduction, nodule leghemoglobin accumulation per nodulated root, total and specific CO2 evolution from nodulated roots and gross CO2 respiratory costs of acetylene reduction. The ‘RisfixC’ also exhibited a substantially lower plant dry mass production (by 30%), but nitrogen concentration in shoots and carotenoid concentration in leaf tissue were significantly higher by 33 and 14%, and the chlorophylla+b content insignficantly higher than in the parental cultivar. In contrast, the nodulation mutant ‘Risnod29’, exhibited a somewhat higher nodule fresh mass accumulation (by 21%) and individual nodule fresh mass (by 23%), total and specific acetylene reduction (by 49 and 19%) and a somewhat more rapid plant dry mass accumulation compared with the cv. Finale. 相似文献
70.
Effect of paclobutrazol onin vitro formation of potato microtubers and their sprouting after storage
I. Šimko 《Biologia Plantarum》1994,36(1):15-20
Paclobutrazol, the gibberellin biosynthesis inhibitor, acceleratedin vitro tuber initiation of potato cv. Rema and increased the uniformity of tuberization period. However, the high concentrations (10–1000 mg l?1) of this retardant, strongly decreased mass and/or number of microtubers. The microtubers were harvested and stored in darkness (22±2°C) for 250 d. After this period both sprouting and growth of sprouts were affected by previous paclobutrazol treatment. 相似文献