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11.
Gunars Lacis Edite Kaufmane Isaak Rashal Viktor Trajkovski Amy F. Iezzoni 《Euphytica》2008,160(2):155-163
The Latvian and the Swedish sweet cherry (Prunus avium L.) genetic resources collections comprise valuable material for breeding. The collections represent local Latvian and Scandinavian
genetic resources: semi-wild samples, landraces, and cultivars developed in local breeding programmes, as well as diverse
germplasm from the northern temperate zone. The objective of this investigation was to determine which S
1
–S
6
alleles are most important in the sweet cherry genetic resources collections and to compare the identified allelic and genotypic
frequencies in material of different origin. Accessions in the two collections were screened for the presence of the self-incompatibility
(S) S
1
to S
6
alleles, using PCR based typing. Significant differences (P < 0.05) between screened collections were found in frequencies of S
4
and S
5
alleles. Analysis of allele combinations identified the high occurrence of selections with the S-genotype S
3
S
6
in both collections. Compared to the S-allele frequencies published for over 250 sweet cherry cultivars from Western and Southern Europe, the Latvian and Swedish
germplasm appeared to have a high frequency of the S
6
allele in both collections, and a relatively high frequency of the S
5
allele in Latvian germplasm. This study represents the first comprehensive S-allele screening for the sweet cherry genetic resources collections in Latvia and Sweden. Both sweet cherry collections contain
high proportion of accessions adapted to north central European growing conditions, not typical for the majority of the documented
sweet cherry genetic resources, which explains differences in certain S-allele occurrence. 相似文献
12.
Earth's energy imbalance: confirmation and implications 总被引:2,自引:0,他引:2
Hansen J Nazarenko L Ruedy R Sato M Willis J Del Genio A Koch D Lacis A Lo K Menon S Novakov T Perlwitz J Russell G Schmidt GA Tausnev N 《Science (New York, N.Y.)》2005,308(5727):1431-1435
Our climate model, driven mainly by increasing human-made greenhouse gases and aerosols, among other forcings, calculates that Earth is now absorbing 0.85 +/- 0.15 watts per square meter more energy from the Sun than it is emitting to space. This imbalance is confirmed by precise measurements of increasing ocean heat content over the past 10 years. Implications include (i) the expectation of additional global warming of about 0.6 degrees C without further change of atmospheric composition; (ii) the confirmation of the climate system's lag in responding to forcings, implying the need for anticipatory actions to avoid any specified level of climate change; and (iii) the likelihood of acceleration of ice sheet disintegration and sea level rise. 相似文献
13.
Interpretation of snow-climate feedback as produced by 17 general circulation models 总被引:1,自引:0,他引:1
Cess RD Potter GL Zhang MH Blanchet JP Chalita S Colman R Dazlich DA Genio AD Dymnikov V Galin V Jerrett D Keup E Lacis AA LE Treut H Liang XZ Mahfouf JF McAvaney BJ Meleshko VP Mitchell JF Morcrette JJ Norris PM Randall DA Rikus L Roeckner E Royer JF Schlese U Sheinin DA Slingo JM Sokolov AS Taylor KE Washington WM Wetherald RT Yagai I 《Science (New York, N.Y.)》1991,253(5022):888-892
Snow feedback is expected to amplify global warming caused by increasing concentrations of atmospheric greenhouse gases. The conventional explanation is that a warmer Earth will have less snow cover, resulting in a darker planet that absorbs more solar radiation. An intercomparison of 17 general circulation models, for which perturbations of sea surface temperature were used as a surrogate climate change, suggests that this explanation is overly simplistic. The results instead indicate that additional amplification or moderation may be caused both by cloud interactions and longwave radiation. One measure of this net effect of snow feedback was found to differ markedly among the 17 climate models, ranging from weak negative feedback in some models to strong positive feedback in others. 相似文献
14.
Travis LD Coffeen DL Del Genio AD Hansen JE Kawabata K Lacis AA Lane WA Limaye SS Rossow WB Stone PH 《Science (New York, N.Y.)》1979,205(4401):74-76
Ultraviolet images of Venus over a 3-month period show marked evolution of the planetary scale features in the cloud patterns. The dark horizontal Y feature recurs quasi-periodically, at intervals of about 4 days, but it has also been absent for periods of several weeks. Bow-shaped features observed in Pioneer Venus images are farther upstream from the subsolar point than those in Mariner 10 images. 相似文献