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排序方式: 共有1249条查询结果,搜索用时 546 毫秒
941.
942.
Summary An 8 × 8 full diallel experiment based on 4 bunch plus 4 spreading types of groundnut (Arachis hypogaea L.) was conducted over three environments. For both number of pods and pod yield, additive, nonadditive and reciprocal cross effects were detected and these were also influenced by changes in environments. For number of pods additive genetic variance was predominant whereas it was approximately equal to non-additive genetic variance for pod yield. Graphical analysis revealed the presence of strong non-allelic interaction for number of pods whereas for pod yield absence of dominance and/or presence of non-allelic interaction was evident.Part of Ph.D. Thesis of the first author  相似文献   
943.
In the present study, Au(III) and Pt(II) complexes of 1, 10-phenanthroline (phen) were synthesized and used as the test compounds. The structure elucidation of the synthesized compounds was performed by IR, 1H-NMR and MASS spectroscopic data and the results of elemental analyses. The cytotoxic and apoptotic effects of test compounds were elucidated on V79 379A (Chinese hamster lung fibroblast like) and A549 (human lung carcinoma epithelial like) cell lines. Cytotoxicity was measured with MTT assay and antitumoral effect was determined by colony forming ability methods. In addition, nuclear fragmentation and activation of apoptotic enzyme (caspase-3) and DAPI staining were used to detect the apoptotic effect of the compounds. All the test compounds induced time and concentration-dependent cytotoxic and antitumoral effects. Significant increases in the levels of apoptosis were observed with increasing exposure concentration.  相似文献   
944.
A feruloylesterase was purified from the extracellular broth of Aspergillus awamori grown on wheat bran culture. The purified enzyme gave a single band on SDS-polyacrylamide gel electrophoresis and isoelectric focusing, with an apparent M r of 35,000 and a pI of 3.8, respectively. The substrate specificity of the purified enzyme differed obviously from that of acetylesterase of A. awamori. The enzyme bound to microcrystalline cellulose.  相似文献   
945.
946.
947.
The growth retardant paclobutrazol (PBZ) inhibited stem internode growth of in vitro cloned potato plants. The extent of growth inhibition caused by10-9 M PBZ in Murashige and Skoog medium was genotype-specific, varying between 10 - 60% of the stem growth of untreated controls in ten cultivars examined. An increase in percentage of de novo bud regenerating stem internode segments (SIS) as well as in the total number of buds per explant was observed in SIS taken from PBZ pretreated plants. PBZ applied directly into the regenerative media had no stimulatory effect on there generation process. We assume that the enhancing effect of PBZ on regeneration may be attributed to its interaction with cytokinin metabolism. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   
948.
Yellow, red or orange carotenoid-based colorations in male birds are often a signal to prospecting females about body condition, health status and ability to find food. However, this general 'ability to find food' has never been defined. Here we show that more brightly ornamented individuals may also be more efficient when foraging in novel situations. The results highlight the fact that evolution may have provided females tools to evaluate cognitive abilities of the males.  相似文献   
949.
We tested the hypothesis that density‐dependent competition influences the evolution of offspring size. We studied two populations of the least killifish (Heterandria formosa) that differ dramatically in population density; these populations are genetically differentiated for offspring size, and females from both populations produce larger offspring when they experience higher social densities. To look at the influences of population of origin and relative body size on competitive ability, we held females from the high‐density population at two different densities to create large and small offspring with the same genetic background. We measured the competitive ability of those offspring in mesocosms that contained either pure or mixed population treatments at either high or low density. High density increased competition, which was most evident in greatly reduced individual growth rates. Larger offspring from the high‐density population significantly delayed the onset of maturity of fish from the low‐density population. From our results, we infer that competitive conditions in nature have contributed to the evolution of genetically based interpopulation differences in offspring size as well as plasticity in offspring size in response to conspecific density.  相似文献   
950.
Abstract

The title compound 1 is prepared from thymidine 5′-phos-phorodiamidate (2) and inorganic pyrophosphate (3) in anhydrous DMF, at 30–32°C. The products of alkaline hydrolysis of 1, at room temperature, are: thymidine 5′-phosphoramidate (4), thymidine 3′-phosphoramidate (8) and thymidine (9) as well as 3 and inorganic trimetaphosphate (10). In 1 N NH4OH, 1 reacts with cytidine (15) to form cytidylyl-/2T(3′)-5′/-thymidine (16) and a mixture of cytidine 2′,3′-cyclic phosphate (17) and 9.  相似文献   
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