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151.
A simple simulation model of the secondary shrub succession has been elaborated on the grounds of primary field data from abandoned fields of different ages in the area of Bohemian Karst. The model describes vegetational dynamics using adaptedVolterra-Lotka equations for competing species. Carrying capacities and growth rates are expressed as a function of the depth of the soil. 相似文献
152.
Jan Ahlers 《Molecular and cellular biochemistry》1977,15(2):145-148
Summary Bound and solubilized ATPase from Escherichia coli show similar kinetic properties. The saturation curves for MgATP are hyperbolic with both preparations. The straight lines in the Line-weaver–Burk plot indicate that MgATP is the true substrate, that one molecule MgATP is bound per enzyme molecule, and that there is no cooperativity. Presence of EDTA leads to sigmoidal saturation curves. This effect could be reversed by adding MgCl2 stoichiometrically to EDTA.Different results in other publications, especially in that ofCarreira andMuñoz can be explained as being primarily the consequence of complexing agent contaminations in the assay. 相似文献
153.
Martijn H. Breuning Ella M. van den Berg-Loonen Luigi F. Bernini Jan B. Bijlsma Erna van Loghem P. Meera Khan Lourens E. Nijenhuis 《Human genetics》1977,37(2):131-139
Summary A detailed marker gene study in a large Dutch kindred segregating for a reciprocal translocation between the chromosomes 6 and 20, t(6;20) (p21;p13), revealed a close linkage between the HLA genes and the breakpoint on the short arm of 6. During this study an apparent peak lod score of 2.9 was obtained at a recombination value of 0.05 for a linkage between HLA and the breakpoint, indicating that the chromosomal region, carrying the HLA genes, is situated near the breakpoint in band 6p21 close to the transition to 6p22. 相似文献
154.
Hubert G. Theuns Jan E.G. van Dam Jan M. Luteijn Cornelis A. Salemink 《Phytochemistry》1977,16(6):753-755
Three new alkaloids have been identified from Papaver bracteatum, 14-β-hydroxycodeinone, 14-β-hydroxycodeine and N-methylcorydaldine. The presence of alpinigenine was also confirmed. 相似文献
155.
van Onckelen Henri A.; Caubergs Roland; de Greef Jan A. 《Plant & cell physiology》1977,18(5):1029-1040
The influence of light and endogenous plant-growth regulatorson the evolution of - and ß-amylases in cotyledonsof Phaseolus vulgaris L. was investigated. Both enzymes, whichare not present in ungerminated seeds, appear during germinationof intact seedlings or incubation of excised cotyledons. -Amylaseactivity decreases upon exposure to light. This inhibition iscorrelated with a drastic increase in chlorophyll content anda change in the endogenous gibberellin-inhibitor balance. ß-Amylaseactivity was not affected by light treatment but was by thepresence of endogenous cytokinins. (Received February 3, 1977; ) 相似文献
156.
Jan M.C. Geuns 《Phytochemistry》1978,17(1):1-14
The occurrence of steroid hormones in plants is briefly reviewed. Their effects on plant growth, development and flowering are also considered. 相似文献
157.
Jan Jeník 《Folia Geobotanica》1977,12(2):208-208
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