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151.
A study was made of the changes in the content of essential oil and its components (farnesene, (-)-α-bisabolol, (-)-α-bisabololoxide
A, (-)-α-bisabololoxide B and spathulenol, α-bisabolonoxide A, chamazulene, cis en-in-dicycloether) and of the number of secretory
canals in the receptacles during the beginning of flowering, full flowering and the termination of flowering of camomile anthodia.
The total content of the essential oil was highest during the beginning of flowering and lowest during its termination. The
proportion of the individual sesquiterpenes in the essential oil underwent changes mostly during the beginning and termination
of flowering. The number of secretory canals in the basal and middle anthodial parts increased during the beginning of flowering
and the full flowering. 相似文献
152.
Sucrose was markedly superior to fructose and glucose in promoting growth of plantlets from immature maize embryos. The elongation
of roots is shown to be more sucrose dependent than that of shoots. On the other hand, the exogenous sucrose was less effective
than fructose as substrate for carbohydrate catabolism and for the synthesis of alcohol-insoluble compounds at the beginning
of embryo cultivation. The absorbed fructose was found to be rapidly converted to sucrose and the level of endogenous sucrose
derived from sugar supplied to the medium was higher in fructosethan in sucrose-fed embryos. The preferential utilization
of fructose over sucrose, however, declined with the progress of germination which may be related to the decrease in proportion
of scutellum in total mass and physiological activity of the embryo. 相似文献
153.
M. Podojil M. Blumauerová V. Přikrylová Z. Vaněk G. F. Gauze T. S. Maksimova 《Folia microbiologica》1980,25(6):464-466
The strainStreptomyces griseoruber 4620 produces, besides the anthracycline antibiotics beromycins, some other anthracyclines of the rhodomycin type. Twelve
isolates exhibiting a higher antibiotic activity (up to 2.5×), as compared to the parent strain, were obtained after a spontaneous
selection. The following species were isolated from the hydrolysate of mycelial extract: β-rhodomycinone, β-isorhodomycinone,
α2-rhodomycinone and 10-deoxy-β-rhodomycinone, which has not yet been described. 相似文献
154.
155.
156.
Summary LW13K2 cells, a clone of a spontaneously in vitro transformed derivative of embryonic Lewis rat fibroblastic cells, were studied by phase contrast cine-light microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The ruffles found at the advancing edge of cells grown on glass substrates in vitro form and recede in a period of less than one min if they do not make an attachment of the substrate. If they fail to make an attachment they may form pinocytotic channels near the leading edge as described by Price (1972) and/or collapse, generally backwards, towards the cell body. The spines which appear to reinforce the membranous ruffles are the last structures to disappear, and accumulate in an irregular array behind the ruffling edge; this area is behind that in which pinocytosis occurs. In comparison with the sparse numbers of ribosomes found in the trailing edge, they are present in notable concentrations near the leading, ruffling edge of the cell. No membrane vesicles have been found in or near the ruffling edges at the ruffle-spine concentration zone. 相似文献
157.
Jiří Ponert 《Folia Geobotanica》1977,12(1):9-22
Studies of the Adjarian flora resulted in a detailed classification of the ergasiophygophytes, based mainly on the degree of their naturalization: (1) The ephemeroergasiophygophytes display unstable naturalization both in artificial and natural habitats, and disappear after only a few growing seasons. (2) The deuteroergasiophygophtes show stable naturalization in anthropogenic habitats. (3) The protoergasiophygophytes are distinguished by uncertain stability of naturalization in natural habitats, and, if firmly naturalized on a certain spot, they lack any tendency to further spreading. (4) The autergasiophygophytes tend to spread in natural habitats. (5) The aggressive ergasiophygophytes transform natural vegetation in new plant communities, and can become dominant species in these communities. New terms, viz. emphemeroxenophytes, protoneophytes, non-aggressive neophytes, slightly aggressive neophytes, and postneophytes with vegetative reproduction have also been introduced to express diverse features of the xenophytes. 相似文献
158.
The capacity of pollen tubes to utilize exogenous uridine during 8 h of cultivation in shaken suspension in a sugar-mineral
medium was examined by continuous and pulse labelling with3H-uridine. The increase of uptake with increasing concentration of the nucleoside indicated a saturable transport system with
an approximate Km of 9.4 × 10−6 M and 12.5 × 10−6M as determined in 1-h and 6-h cultures, respectively. Maximal uptake took place at the beginning of germination reaching
a rate of about 2 nmol h−1 per 1 mg of dry pollen at 0.1 mM external uridine. The uptake activity decreased with the time of pollen tube growth to less
than one third during the 8-h cultivation period. Moreover, the level of radioactivity taken up initially decreased later
on during continuous cultivation in the presence of3H-uridine. The uptake took place against a concentration difference and the onset and rate of uridine release depended on
its exogenous concentration.
The activity of the nucleoside incorporation into RNA increased during the first 4 h of cultivation, decreasing later on.
The proportion of RNA radioactivity in continuously labelled pollen tubes grew steadily during 6 h and reached 2.5% with respect
to soluble pool at 0.4 μM uridine. The time course of RNA labelling was independent of uridine concentration within the range
of 0.4 μM to 40 μM but this concentration rise resulted in an about fiftyfold increase of the total amount of external uridine
incorporated. 相似文献
159.
160.
A new mannose-resistant haemagglutinin in Klebsiella 总被引:1,自引:1,他引:0
Strains of Klebsiella of the species (or 'patho-bio-sero-geogroups') Kl. atlantae, Kl. edwardsii and Kl. rhinoscleromatis produced neither haemagglutinins (HAs) nor fimbriae; strains of Kl. ozaenae were HA- but some produced type-6 fimbriae; and strains of Kl. pneumoniae ( sensu stricto ) and Kl. aerogenes that produced the mannose-sensitive HA (MS-HA) formed type-1 fimbriae. Most strains of Kl. aerogenes produced, in addition, one or both of the mannose-resistant HAs, MR/K-HA or MR/P-HA. The former, associated with type-3 fimbriae, was produced by 95%, and the latter by 57%, of the Kl. aerogenes strains. Some of the properties of the MR/P-HA, apparently a non-fimbrial HA not previously recognised in Klebsiella , are described. 相似文献