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61.
The pattern of the activity of arginine decarboxylase (ADC) and omithine decarboxylase (ODC) involved in polyamine synthesis
in ripening wheat seeds was examined. The aim was to study the polyamines and the activity of the two enzymes in correlation
with the growth processes occurring in the developing wheat seeds. The results obtained showed a very different pattern of
polyamine content in the two organs of caryopsis, and that the two enzymes in the embryos have a higher activity than in the
endosperms. Moreover, while in the embryos the ADC exhibits higher activity than the ODC, in the endosperms the activity of
ODC is about similar to that of ADC. This pattern is discussed in relation to the different histological characteristics of
embryo and endosperm tissues during seed development. 相似文献
62.
Effects of cooling water discharge on the structure and dynamics of epilithic algal communities in the northern Baltic 总被引:1,自引:0,他引:1
The Forsmark Biotest Basin is a shallow coastal ecosystem that receives brackish cooling-water discharge from a nuclear power
plant. The effects of the discharge on epilithic algal communities were investigated by analysing samples taken every third
week throughout one year at 11 sites differentially affected by temperature and/or flow rate enhancement. Community variation
was summarized in a canonical correspondence analysis (CCA) of species abundances as a function of site and date. The temperature
increase favoured blue-green algae at the expense of red and brown algae. Blue-green algae were however abundant in summer
in stagnant water, whether heated or not, and some red and brown algae became abundant in winter in heated sites with flowing
water. Green algae and diatoms increased in biomass in the heated sites, but not in relative cover-abundance. The absence
of ice and snow cover at sites with heated and/or flowing water caused autumn species to persist into winter, because of the
higher light intensity (compared with natural conditions) and the absence of the mechanical abrasion by ice. The thermal discharge
lowered species diversity (Shannon-Weaver index) both in summer and winter at sites with flowing water, but not at sites with
quiescent or stagnant water. CCA showed alternate periods of stability and rapid change within the seasonal cycle. Individual
species were placed according to their optimum; red and brown algae in winter/spring, green algae in spring/summer, blue-green
algae in summer, and diatoms at various times. Exceptions to this pattern were species endo- or epiphytic on species of a
different group. Analysis of the effects of temperature, flow rate and ice cover on the seasonal pattern of particular species
showed that different species respond in individualistic ways to different combinations of these environmental variables. 相似文献
63.
Synopsis The Oreochromis mossambicus population of North Pine Dam, Brisbane, Queensland, Australia was studied over three years, from 1985 to 1988. Basic somatic data were obtained and characteristic values of condition factor, sex ratio, gonosomatic index and the relationships between total and standard lengths, and length and weight, were calculated. Standard length is proportional to total length by the formula SL = –0.321 + 0.799 TL. Weight is related to length by the isometric formula W = aL3. Condition factor values spanned the range 0.0254 to 0.0563, with an average of 0.04078 for males and 0.03877 for females. The sex ratio is 1: 1 until maturity is reached (21 cm SL), at which time the catch rate of the sexes varies due to divergent habitat selection behaviour. Average values of gonosomatic index, considered in relation to maturity classification, are similar to those obtained from other populations, however maximum values are generally much lower, at 0.47 for males and 3.62 for females. These characteristic values are compared, with varying degrees of concordance, with those for populations of this species in other countries. 相似文献
64.
A simple procedure is described for the determination of the photosensitizing potency of drugs, using three leukemic cell lines, two of lymphocytic origin, L1210 and P388 and one of erythroid type, Friend-745. The procedure allows one to investigate several aspects of the photosensitization properties of tested compounds such as cellular localization and direct (trypan blue exclusion) or delayed (clonogenicity) photomediated toxicities.The method was assessed using crude hematoporphyrin derivative (HPD) as well as dihematoporphyrin ether (DHE) or commercially available Photofrin II. Results were compared to those obtained with normal cells, e.g spleen lymphocytes and erythropoietic stem cells (CFU-e), and discussed in the light of the relative response of normal versus transformed cells.Abbreviations DHE
Dihematoporphyrin Ether
- FCS
Fetal Calf Serum
- HPD
Hematoporphyrin Derivative
- PDT
Photodynamic Therapy 相似文献
65.
Toshiyuki Sato 《Journal of plant research》1990,103(2):165-176
A quantitative comparison was conducted on the foliage development during sporophyte development of three allopatric ferns
in cool temperate and subalpine regions of Hokkaido and Tirol, European Alps. The foliage development ofDryopteris crassirhizoma, D. coreano-montana andD. filix-mas was quantitatively described by the leaf development (NV, number of veins); NV correlates the leaf-shape complexity from
a circle (DI, L/2(3.14×S)1/2). Nearly similar patterns were detected on frequency distribution of fertile leaves, fertility increase and number of leaves
in threeDryopteris ferns which exhibit funnel-shaped foliage arrangements in mature sporophyte. No difference was found in number of leaves,
maximum NV, fertility rate and leaf-shape parameters among three ferns. A positive difference was found only on changes in
order of pinnae with maximum number of costa branches (NVP) and the DI of outline of pinnae betweenD. crassirhizoma andD. filix-mas. These allopatricDryopteris ferns seem to have a similar foliage structure, in spite of some sympatricDryopteris ferns capable of producing putative hybrids (D. austriaca andD. amurensis; D. tokyoensis andD. monticola) having different foliage structures in Hokkaido.
Contribution No. 3346 from the Institute of Low Temperature Science, Hokkaido University. 相似文献
66.
桂西壮族手皮纹的分析 总被引:4,自引:0,他引:4
本文对广西西部500例健康壮族大、中学生的手皮纹进行了观察分析,计算出各型指纹频率、指纹脊线总数、指纹频度指数、atd角度、a-b脊线数、τ距比、主线横向指数、皮纹花样出现率、掌褶纹出现率共九项基本参数,并将这些数值与汉族作了比较,桂西壮族的手纹与汉族既有相似之处,又有本民族的特点。 相似文献
67.
A firm, mobile, oblong mass was discovered as an incidental finding in the stomach of a chimpanzee (Pan troglodytes) during routine surgery. It was removed and determined to be a trichobezoar. 相似文献
68.
U. M. Cowgill 《Biological trace element research》1988,17(1):43-67
Vegetation growing in the Ely mining district of White Pine County, NV has been analyzed for tellurium to discover whether
Te accumulator plants existed similar to those that take up Se in great quantities. In addition, the variation in Te content
among species growing in different geological settings was studied. Another objective of this study was to determine the range
of Te concentration in vegetation in regions where the Te content of surface materials was high, as in the Ely mining district,
and low as in various areas of western CO. Trees and shrubs (480 samples) as well as flowering plants (505 samples) and their
associated edaphic materials were collected from six sites in the Ely region and all plant parts were analyzed for Te, Se,
Fe, S, Zn, Cu, and Pb. One hundred and five plants were collected from three areas in western CO.
There is a highly significant difference between Te uptake by trees and that of perennial flowering plants. Flowers contain
significantly more Te on the average than other plant parts. An examination of the Te content of tree parts reveals that leaves
sorb the most and branches the least. When the Te content of edaphic materials is high, there is a corresponding increase
in the Te content of plants. Shallow perennial plants were not found growing in areas where soils contained more than 10 mg
kg−1 Te. Seleniferous species ofAstragalus contain larger quantities of Te than plants in the Ely area, whereas nonseleniferous members of this genus contain much less.
The nitrotoxin producing Astragali contain concentrations of Te greater than that encountered in nonseleniferous species but
less than that in seleniferous ones. No plants contained more than 1 mg kg−1 Te. Iron, Te, Se, and S are coherent in all plants and in most soils and rocks examined. 相似文献
69.
Paul N. Newton 《Plant Ecology》1988,75(1-2):3-16
The vegetation structure and phenology of a 74.5 ha block of moist deeiduous forest in Kanha Tiger Reserve, Madhya Pradesh, India were investigated during primatological fieldwork. Within a grid of 0.25 ha quadrats all 9935 trees (woody plants > 2 m tall), of 63 species, were enumerated and their girth measured. The forest was dominated by the dipterocarp sal (Shorea robusta). Most species were rare and showed clumped distributions within the sea of sal whilst the dispersion of five large canopy trees could not be distinguished from random.The phenology of 215 trees, of 61 species, was monitored over 14 months using an index of phytophase abundance. Leaf renewal was highly synchronous between and within species, mostly occurring between February and June. One species was evergreen, 5 were semi-evergreen and 55 were deciduous. Flowering generally occurred between leaf fall and flush whilst fruiting peaked late in the hot weather and early monsoon. 相似文献
70.