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排序方式: 共有48条查询结果,搜索用时 15 毫秒
21.
为了对秦岭野生宜昌百合资源进行保存,并有效地解决其扩繁和再生问题,以秦岭野生宜昌百合为材料,研究不同质量浓度的激素组合、鳞片的不同部位及光暗培养对秦岭野生宜昌百合的体细胞胚诱导的影响。结果表明,鳞片诱导体细胞胚的适宜培养基为MS+0.5 mg/L TDZ(N-苯基-N-′1,2,3-噻二唑-5-脲)+1.0 mg/L NAA(a-萘乙酸)。鳞片基部诱导体胚率最高,为90.00%,鳞片分化体细胞胚的能力为基部>中部>上部。暗培养下诱导率为90.00%,高于光培养条件。 相似文献
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Marina Mosbæk Johannessen Christian Damgaard Bente Anni Andersen Rikke Bagger Jørgensen 《Euphytica》2006,150(1-2):17-25
Summary Interspecific F1-hybrids may arise in fields with transplastomic oilseed rape where B. rapa occurs as a weed. Spilled seeds, including transplastomic F1-hybrids with B. rapa, may germinate, which creates an opportunity for production of transplastomic BC1 with B. rapa as father (BC1r). Field trials were made with three different proportions of B. napus, B. rapa and F1-hybrids and three different densities. Contrary to most studies on how plant competition affects introgression between oilseed rape and B. rapa, this study focused on offspring produced on F1-hybrids, where the F1-hybrids had oilseed rape as maternal parent. We estimated the BC1r production in all combinations of proportion and density, and found that B. rapa sired from 0.6–7.8% of the offspring. At the proportion with the highest abundance of F1-hybrids the entire paternity was assessed. There was a significant density effect on the production of BC1r but the effect differed among proportions. Both the highest and lowest frequencies of BC1r were obtained at high plant density. Neither the proportion nor density affected the number of BC1r per square-meter significantly. Biomass components decreased significantly from low to intermediate density, whereas a further increase in density only affected the thousand-seed weight significantly. On the basis of the results from the present experiment we conclude that introgression of transgenes from transplastomic oilseed rape to B. rapa seems most likely at current field densities of B. napus, and when B. rapa is an abundant weed. 相似文献
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Chromosomal regions associated with the in vitro culture response of wheat (Triticum aestivum L.) microspores 下载免费PDF全文
Nanna H. Nielsen Stig U. Andersen Jens Stougaard Anni Jensen Gunter Backes Ahmed Jahoor 《Plant Breeding》2015,134(3):255-263
Generation of doubled haploid plants is a powerful tool in breeding, as homozygous individuals will be obtained directly from hybrids. However, genotype variability in regeneration efficiency of most European wheat (Triticum aestivum L.) varieties has limited its use in wheat. This study intended to identify quantitative trait loci (QTLs) for green plantlet regeneration from wheat microspore cultures. A QTL analysis using DArT markers was conducted based on a bi‐parental F3 population, derived from a cross between the varieties Svilena and Jensen, which displayed markedly different capacity for plantlet regeneration. Two QTLs on chromosome 1B and 7B explained 53% of the variation in green plantlet regeneration. Furthermore, a collection of 94 European wheat varieties was genotyped and phenotyped. The microspore response level was low among western and northern European wheat varieties, and the positive QTLs found in the bi‐parental population were rare in the variety collection. Identification of the two QTLs enables introduction of high regeneration efficiency into wheat germplasm. Moreover, our results proved that the efficient regeneration observed for one variety could be crossed into modern winter wheat. 相似文献
26.
Flood or drought: how do aerosols affect precipitation? 总被引:4,自引:0,他引:4
Rosenfeld D Lohmann U Raga GB O'Dowd CD Kulmala M Fuzzi S Reissell A Andreae MO 《Science (New York, N.Y.)》2008,321(5894):1309-1313
Aerosols serve as cloud condensation nuclei (CCN) and thus have a substantial effect on cloud properties and the initiation of precipitation. Large concentrations of human-made aerosols have been reported to both decrease and increase rainfall as a result of their radiative and CCN activities. At one extreme, pristine tropical clouds with low CCN concentrations rain out too quickly to mature into long-lived clouds. On the other hand, heavily polluted clouds evaporate much of their water before precipitation can occur, if they can form at all given the reduced surface heating resulting from the aerosol haze layer. We propose a conceptual model that explains this apparent dichotomy. 相似文献
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Heng BC Bezerra PP Meng QR Chin DW Koh LB Li H Zhang H Preiser PR Boey FY Venkatraman SS 《Biointerphases》2010,5(3):FA53-FA62
This study characterized human umbilical vein endothelial cell (HUVEC) adhesion, proliferation, and gene expression on bilayered polyelectrolyte coatings composed of an outermost layer of glycosaminoglycans (hyaluronan, heparin, or chondroitin sulfate), with an underlying layer of poly-L-lysine or chitosan. The proportion of cells that adhered to the various polyelectrolyte coatings after 1 and 2 h incubations was quantified by the WST-8 assay. Interchanging poly-L-lysine with chitosan resulted in significant differences in cellular adhesion to the outermost glycosaminoglycan layer after 1 h, but these differences became insignificant after 2 h. The proliferation of HUVEC on the various bilayered polyelectrolyte coatings over 10 days was characterized using the WST-8 assay. Regardless of whether the underlying layer was poly-L-lysine or chitosan, HUVEC proliferation on the hyaluronan outermost layer was significantly less than on heparin or chondroitin sulfate. Additionally, it was observed that there was more proliferation with poly-L-lysine as the underlying layer, compared to chitosan. Subsequently, real-time polymerase chain reaction was used to analyze the expression of seven genes related to adhesion, migration, and endothelial function (VWF, VEGFR, VEGFA, endoglin, integrin-α5, ICAM1, and ICAM2) by HUVEC cultured on the various bilayered polyelectrolyte coatings for 3 days. With poly-L-lysine as the underlying layer, biologically significant differences (greater than twofold) in the expression of VWF, VEGFR, VEGFA, endoglin, and ICAM1 were observed among the three glycosaminoglycans. With chitosan as the underlying layer, all three glycosaminoglycans displayed biologically significant differences in the expression of VWF and VEGFR compared to the chitosan control. CT-HA displayed the highest level of expression of VWF, whereas expression levels of VEGFR were almost similar among the three glycosaminoglycans. 相似文献
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Ilpo Niskanen Jorma Heikkinen Jukka Mikkonen Anni Harju Henrik Heräjärvi Martti Venäläinen Kai-Erik Peiponen 《Journal of Wood Science》2012,58(1):46-50
The purpose of this study was to determine the effective refractive index of thermally modified Scots pine (Pinus sylvestris L.) wood specimens as a quantitative measure regarding the change of wood density which is due to the thermal modification.
The refractive index of thermally modified Scots pine wood was obtained by introducing pine wood powder into an immersion
liquid and measuring light backscattering with a homebuilt multifunction spectrophotometer. The present method provides useful
information that in principle can be applied, for example, in the optimization of the thermal modification process and inspection
of the quality of thermally modified wood. 相似文献
30.
Terttu Kämäräinen-Karppinen Anni Mäkinen Sonja Kolehmainen Aino Hämäläinen Kari Laine Anja Hohtola 《The Journal of Horticultural Science and Biotechnology》2013,88(6):765-769
SummaryFrench tarragon (Artemisia dracunculus var. sativa) has been vegetatively propagated for centuries, but variability in the vegetative lines has not been studied. Three lines of French tarragon (A – C) were studied for their overwintering capacity at the limit of survival, their essential oil content and composition, and their genetic variability. Line B had the lowest Winter survival rate, the highest biomass yield, and the lowest content of essential oils. The essential oils of line B had higher proportions of cis- and trans-ocimenes, and contained less estragole and herniarin than the essential oils of lines A and C. When genetic diversity was studied using restriction fragment length polymorphism (RFLP), all French tarragon lines clustered together, while Russian tarragon was monophyletic. Lines A and B were genetically closer to each other than line C. These results indicate that all three lines tested were genetically and biochemically different, which may have resulted from spontaneous mutations over centuries of vegetative propagation. Our results demonstrate the need to monitor and preserve the most important traits for future cultivation and use of vegetatively propagated herbs. 相似文献