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11.
利用染色体配对分析和酯酶及种子醇溶蛋白电泳分析研究了我国育成的11个八倍体小偃麦,结果表明:(a)来源于小麦和中间偃麦草杂交后代的6个部分双二倍体中,中1和中2的偃麦草染色体组不同于中3、中4、中5和小偃78829的偃麦草染色体组;(b)来源于小麦和长穗偃麦草杂交后代的5个部分双二倍体中,小偃784的偃麦草染色体组不同于小偃693和小偃7631中的偃麦草染色体组,表明在长穗偃麦草中有两个互不相同又不同于小麦的染色体组E和F,而小偃7430和小偃68中的偃麦草染色体组很可能是E和F染色体组的重组体;(c)小偃784中的长穗偃麦草染色体组和中5及小偃78829中的中间偃麦草染色体组基本相同,而中2的中间偃麦草染色体组不同于小偃693和小偃7631中的长穗偃麦草染色体组F,这意味着在长穗偃麦草和中间偃麦草中可能只有一个共同的染色体组E。部分双二倍体中酯酶及醇溶蛋白偃麦草染色体特征带的存在和发现,为这些染色体或其片段导入小麦后的鉴定提供了方便。 相似文献
12.
Y. S. Xu M. Murto R. Dunckley M. G. K. Jones E. Pehu 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1993,85(6-7):729-734
Summary Asymmetric somatic hybrids were obtained by fusion of Solanum tuberosum (PDH40) protoplasts with 300- or 500-Gy irradiated protoplasts of S. brevidens. These radiation doses were sufficient to prevent the growth of the S. brevidens protoplasts. Putative hybrids were selected on the basis of phenotype from regenerated shoots and identified with a S. brevidens-specific probe. From these, 31 asymmetric hybrids were confirmed by morphological characteristics, isoenzyme patterns and RFLP analysis. The morphology of the asymmetric hybrids was intermediate between that of S. tuberosum and symmetric hybrids of both species (obtained without irradiation treatment). Chromosome counts from 17 asymmetric hybrids showed that the chromosome number of the hybrids ranged from 31 to 64. The asymmetric hybrids probably had one or two genome complements (i.e. either 24 or 48 chromosomes) from S. tuberosum and 7–22 chromosomes from S. brevidens. There was no clear correlation between the radiation dose and the degree of elimination of the S. brevidens genome. 相似文献
13.
Abstract. Species composition patterns and vegetation-environment relationships were quantified for high-elevation rock outcrops of the Southern Appalachian Mountains, an infrequent and insular habitat in a forested landscape. Outcrops occur over a wide geographic range encompassing extensive variation in both geology and climate. Geographic-scale factors interact with site-scale factors to produce variation in vegetation among outcrops. Similarly, site-scale factors interact with micro-scale factors to produce variation in vegetation within outcrops. To provide a quantitatively-based classification of outcrop vegetation we used a TWINSPAN analysis of 154 100-m2 plots. We recognized nine communities that primarily correspond to different combinations of elevation, bedrock type, geography, and moisture. Within outcrops of a single bedrock type, vegetation composition of 100-m2 plots was consistently correlated with elevation and solar radiation, but relationships to soil nutrients varied with bedrock type. Both site-scale (100 m2) factors (e.g. elevation, slope, aspect, and bedrock type) and plot-scale (1-m2) microsite factors (e.g. soil depth, vegetation height, soil nutrients) were strongly correlated with species composition at the 1-m2 level. Environment can be used to predict composition more effectively for 100-m2 plots on a single bedrock type than either across bedrock types or at a 1-m2 scale. Composition-environment relationships resemble those described for outcrop systems from other regions with pronounced topographic relief more than they do those described for the nearby but flatter and lower-elevation outcrops of the Southeastern Piedmont. There is strong spatial autocorrelation in this community, perhaps owing to dispersal limitation. Consequently, a comprehensive conservation strategy must include reservation of both a range of geologic types and a range of geographic locations. 相似文献
14.
The asymptotic information in censored survival data 总被引:2,自引:0,他引:2
15.
John R. Bearder Jake MacMillan Bernard O. Phinney James R. Hanson Douglas E.A. Rivett Christine L. Willis 《Phytochemistry》1982,21(9):2225-2230
Gibberellin A13 7-aldehyde, previously proposed as an intermediate in the fungal biosynthesis of gibberellin A3, has been prepared from gibbere 相似文献
16.
G M Ledda A Columbano P M Rao S Rajalakshmi D S Sarma 《Biochemical and biophysical research communications》1980,95(2):816-821
In order to characterize rat liver DNA replicated on a carcinogen-damaged template, the replicated DNA was treated with S1-nuclease and the release of (14C)-dimethyl-nitrosamine induced 06-methylguanine, a lesion associated with miscoding and N-7-methylguanine, a lesion that does not miscode were monitored. The results indicated that both the methylated guanines became susceptible to S1-nuclease upon replication. However, a greater percentage of 06-methylguanine (22% of the total 06-methylguanine present in the DNA) compared to N-7-methylguanine (4% of the total N-7-methylguanine present in the DNA) was rendered acid soluble by S1-nuclease. The preferential release of 06-methylguanine compared to N-7-methylguanine from replicated DNA was interpreted to indicate its occurrence in local denatured regions probably generated as a result of misbase pairing. 相似文献
17.
18.
19.
V. Prakash 《Journal of biosciences》1982,4(3):347-359
The interaction of α-globulin with urea/guanidine hydrochloride was investigated by determining the apparent partial specific
volumes of the protein in these solvents. The apparent partial specific volumes were determined both under isomolal and isopotential
conditions. The preferential interaction parameter with solvent components calculated were 0.08 and 0.1 g of urea and guanidine
hydrochloride respectively per g protein. In both the cases the interaction was not preferential with water. The total binding
of denaturant to α-globulin was calculated both for urea and guanidine hydrochloride and the correlation between experimentally
determined number of mol of denaturant bound per mol of protein and the total number of peptide bonds and aromatic amino acids
were found to be in excellent agreement with each other. The changes in volume upon transferring α-globulin from a salt solution
to 8 M urea and 6 M guanidine hydrochloride were also calculated.
This work was done at the Biochemistry Department, Brandeis University, Waltham, Massachusetts 02254, USA. 相似文献
20.
Summary We analyze the global behaviour of a vector disease model which involves spatial spread and hereditary effects. This model can be applied to investigate growth and spread of malaria. No immunization is considered. We prove that, if the recovery rate is less than or equal to a threshold value, the disease dies out, otherwise the infectious people density tends to a homogeneous distribution. Our results follow using contracting convexes techniques and agree with the results given by K. L. Cooke for the model without diffusion.Work supported by C.N.R., Grant No. 79.00696.01. 相似文献