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381.
Blanka Desortov 《International Review of Hydrobiology》1981,66(2):153-169
Parallel determinations of phytoplankton biomass and chlorophyll-α concentration were carried out on five reservoirs. Highly significant positive correlations between phytoplankton biomass values and chlorophyll-α values were found. The possibility of finding a conversion factor linking these two parameters is discussed. The chlorophyll content per unit phytoplankton biomass encountered during the period of study in all reservoirs varied between 0.14 and 3.41% of fresh weight. The influence of light intensity, nutrient concentration and species composition on chlorophyll content per unit phytoplankton biomass is considered. 相似文献
382.
Phototropic sensitivity of forest wood seedlings to lateral illumination was proposed as an early assay for distinquishing various ecotypes of woody plants of the same species. Statistical analysis showed that results were significantly influenced by heterogenity of experimental material caused by an interference of phototropic movements and natural oscillations of hypocotyl. Both movements of pine seedlings (Pinus silvestris L.) were registered by phase photography and their mechanism was analyzed. The apical part of growing hypocotyl illuminated from above oscillates in a space spiral with frequency 3.3 h at mean growth rate 0.66 mm h?1. The mean size of spiral amplitudes is 2.9 mm. The oscillation rhythm is disturbed after the lateral illumination and a phase shift was observed as a result. A new oscillation rhythm with frequency 3.9 h and mean growth rate 0.69 mm h?1 was stabilized after a period of time equal to one nutation turn. Oscillation amplitudes were increased to 4.3 mm. In addition to the radiation intensity the appearance of the phototropic response to light pulse is first of all effected by the actual position of the apical part of hypocotyl in the course of endogenous circumnutations. A uniform plant material for the early assay may be obtained by selection of seedlings which are at the beginning of lateral illumination in the same phase of nutation rhythm. Under such conditions the deviations of longitudinal axis of oscillating spirals characterize the actual phototropic curvature. 相似文献
383.
384.
Cotyledons of 15 day-old seedlings of fiveBrassica oleracea L. varieties were surveyed to identify salient anatomical features. Both palisade parenchyma cells present in the first subepidermal layer and stomata were found to differ in size. 相似文献
385.
Suppression of Adsorption Properties of a z Mutant of Bacteriophage T4 by r Mutations 总被引:1,自引:1,他引:0 下载免费PDF全文
Blanka Rutberg 《Journal of virology》1970,5(5):656-658
The products of bacteriophage T4 r genes influence the organization of the phage-adsorption apparatus in a noncatalytic way. 相似文献
386.
Jan Kaštovský Tomáš Hauer Jan Mareš Markéta Krautová Tomáš Bešta Jiří Komárek Blanka Desortová Jiří Heteša Alica Hindáková Václav Houk Emil Janeček Radovan Kopp Petr Marvan Petr Pumann Olga Skácelová Eliška Zapomělová 《Biological invasions》2010,12(10):3599-3625
The invasion and spread of non-native species of many different kinds of organisms is of increasing interest to researchers. Invasions by microscopic organisms, however, are poorly understood, and their impact on the environment is probably underestimated. We collected available data on non-native and invasive/expansive algae and cyanobacteria in the Czech Republic; we mapped their distribution and assessed their impact on local species and other real or potential risks resulting from their spread. The list of alien species in the Czech Republic contains 10 species of cyanobacteria, 9 species of Bacillariophyceae, 1 species of Dinophyta, 1 species of Ulvophyceae, 2 species of Chlorophyceae, and 1 species complex of Zygnematopyceae. The literature on the worldwide occurrence of these taxa is also reviewed. 相似文献
387.