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921.
922.
Yan Xiao Junbing Tang Hua Qing Changfang Zhou Weijing Kong Shuqing An 《Hydrobiologia》2011,658(1):353-363
The purpose of this article was to study the trade-offs among vegetative growth, clonal, and sexual reproduction in an aquatic
invasive weed Spartina alterniflora that experienced different inundation depths and clonal integration. Here, the rhizome connections between mother and daughter
ramets were either severed or left intact. Subsequently, these clones were flooded with water levels of 0, 9, and 18 cm above
the soil surface. Severing rhizomes decreased growth and clonal reproduction of daughter ramets, and increased those of mother
ramets grown in shallow and deep water. The daughter ramets disconnected from mother ramets did not flower, while sexual reproduction
of mother ramets was not affected by severing. Clonal integration only benefited the total rhizome length, rhizome biomass,
and number of rhizomes of the whole clones in non-inundation conditions. Furthermore, growth and clonal reproduction of mother,
daughter ramets, and the whole clone decreased with inundation depth, whereas sexual reproduction of mother ramets and the
whole clones increased. We concluded that the trade-offs among growth, clonal, and sexual reproduction of S. alterniflora would be affected by inundation depth, but not by clonal integration. 相似文献
923.
924.
Nine new triterpenoid saponins (1–9) have been isolated from the roots of Gypsophila perfoliata Linn. Their structures were established on the basis of extensive NMR (1H, 13C, HSQC and HMBC) and ESIMS studies. 相似文献
925.
926.
927.
Three monoterpenoids and two triterpenoids were isolated from Abiesnephrolepis together with 53 known terpenoids. The structures of the compounds were established by 1D and 2D NMR spectroscopy. The absolute configuration of 3-hydroxycamphane-2-carboxylic acid was established as (1S,2R,3S,4R) by Cu-Kα X-ray crystallography. All 58 isolates were tested for cytotoxic activity against four tumor cells viz. A549 (human lung adenocarcinoma), Colo205 (colon adenocarcinoma), QGY-7703 (human hepatoma) and THP-1 (human monocytic leukemia). α-Cadinol exhibited the best effects on A549, Colo205 and QGY-7703 with IC50 values of 8.6, 8.1 and 4.6 μg/mL, respectively. 相似文献
928.
By analyzing the steroidal content of fresh whole plants of Tacca subflabellata (Taccaceae), we isolated one sapogenin and eight glycosides with four kinds of steroidal skeletons including four new glycosides, named taccasubosides A-D (1-4), together with five known compounds. Among them, compound 1 is the first pentacyclic sterol glycoside with 6-6-6-5-6 fused rings. The structures of 1-4 were elucidated on the basis of extensive spectroscopic analysis, including that of 2D NMR data, and the results of acidic hydrolysis. The cytotoxicity of the selected steroidal glycosides (1-4, 8, and 9) was evaluated in vitro against five human cancer cell lines. Compound 9 showed significant inhibitory activity against all five cell lines. 相似文献
929.
930.
Identification and mapping of a new powdery mildew resistance gene on chromosome 6D of common wheat 总被引:1,自引:0,他引:1
Ma H Kong Z Fu B Li N Zhang L Jia H Ma Z 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2011,123(7):1099-1106
Powdery mildew, caused by Blumeria graminis f. sp. tritici, is one of the most serious wheat diseases. The rapid evolution of the pathogen's virulence, due to the heavy use of resistance genes, necessitates the expansion of resistance gene diversity. The common wheat line D57 is highly resistant to powdery mildew. A genetic analysis using an F(2) population derived from the cross of D57 with the susceptible cultivar Yangmai 158 and the derived F(2:3) lines indicated that D57 carries two dominant powdery mildew resistance genes. Based on mapping information of polymorphic markers identified by bulk segregant analysis, these two genes were assigned to chromosomes 5DS and 6DS. Using the F(2:3) lines that segregated in a single-gene mode, closely linked PCR-based markers were identified for both genes, and their chromosome assignments were confirmed through linkage mapping. The gene on chromosome 5DS was flanked by Xgwm205 and Xmag6176, with a genetic distance of 8.3 cM and 2.8 cM, respectively. This gene was 3.3 cM from a locus mapped by the STS marker MAG6137, converted from the RFLP marker BCD1871, which was 3.5 cM from Pm2. An evaluation with 15 pathogen isolates indicated that this gene and Pm2 were similar in their resistance spectra. The gene on chromosome 6DS was flanked by co-segregating Xcfd80 and Xmag6139 on one side and Xmag6140 on the other, with a genetic distance of 0.7 cM and 2.7 cM, respectively. This is the first powdery mildew resistance gene identified on chromosome 6DS, and plants that carried this gene were highly resistant to all of the 15 tested pathogen isolates. This gene was designated Pm45. The new resistance gene in D57 could easily be transferred to elite cultivars due to its common wheat origin and the availability of closely linked molecular markers. 相似文献