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蓬勃发展的比利时杜鹃产业 总被引:1,自引:0,他引:1
规格和造型不容忽视
位于比利时东佛兰德省的洛克里斯蒂地区(Lochristi)是著名的杜鹃繁育和生产中心,这里活跃着150多家苗圃,杜鹃年产量为4000万株,其中95%用于出口。 相似文献
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The orthorhombic crystal structures of shattuckite, Cu(5)( SiO(3))(4)(OH)(2) and planchétite, Cu(8)(Si(4)0(11))(2)(OH)(4) H(2)O, have been solved. Shattuckite contains silicate chains similar to pyroxene in a complex association with copper atoms, while the closely related planchéite contains silicate chains similar to amphibole. 相似文献
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Martin MW Grazhdankin DV Bowring SA Evans DA Fedonkin MA Kirschvink JL 《Science (New York, N.Y.)》2000,288(5467):841-845
A uranium-lead zircon age for a volcanic ash interstratified with fossil-bearing, shallow marine siliciclastic rocks in the Zimnie Gory section of the White Sea region indicates that a diverse assemblage of body and trace fossils occurred before 555.3 +/- 0.3 million years ago. This age is a minimum for the oldest well-documented triploblastic bilaterian Kimberella. It also makes co-occurring trace fossils the oldest that are reliably dated. This determination of age implies that there is no simple relation between Ediacaran diversity and the carbon isotopic composition of Neoproterozoic seawater. 相似文献
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Mikaela Schmitt-Harsh Tom P. Evans Edwin Castellanos J. C. Randolph 《Agroforestry Systems》2012,86(2):141-157
Tree removal in Latin American coffee agroforestry systems has been widespread due to complex and interacting factors that include fluctuating international markets, government-supported agricultural policies, and climate change. Despite shade tree removal and land conversion risks, there is currently no widespread policy incentive encouraging the maintenance of shade trees for the benefit of carbon sequestration. In facilitation of such incentives, an understanding of the capacity of coffee agroforests to store carbon relative to tropical forests must be developed. Drawing on ecological inventories conducted in 2007 and 2010 in the Lake Atitlán region of Guatemala, this research examines the carbon pools of smallholder coffee agroforests (CAFs) as they compare to a mixed dry forest (MDF) system. Data from 61 plots, covering a total area of 2.24 ha, was used to assess the aboveground, coarse root, and soil carbon reservoirs of the two land-use systems. Results of this research demonstrate the total carbon stocks of CAFs to range from 74.0 to 259.0 Megagrams (Mg)?C ha?1 with a mean of 127.6?±?6.6 (SE)?Mg?C ha?1. The average carbon stocks of CAFs was significantly lower than estimated for the MDF (198.7?±?32.1?Mg?C?ha?1); however, individual tree and soil pools were not significantly different suggesting that agroforest shade trees play an important role in facilitating carbon sequestration and soil conservation. This research demonstrates the need for conservation-based initiatives which recognize the carbon sequestration benefits of coffee agroforests alongside natural forest systems. 相似文献
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Six groups of 0 + marron Cherax tenuimanus were reared on commercial marron diets based on two different fish meals in a study lasting 4 months. Both diets were prepared in a stable and an unstable pelleted form. Matron fed with koi carp or salmon diet and unfed were used as reference groups. Matron were reared communally in tanks (5 m−2 ) and individually in an intensive crayfish culture system (ICCS, 25 m−2 ). Marron were fed at the rate of 6.5% of their body weight per week. Groups fed with stable diets showed larger weight increment at moult, shorter intermoult period, and higher specific growth rate than groups fed with similar unstable diets. Stable matron diets resulted in faster growth than fish diets. There were no differences in hepatopancreatic indices of marron fed with stable diets or similar unstable diets in the ICCS. The condition of hepatopancreata of marron reared in communal tanks were better than those of marron reared in the ICCS on a similar diet. Results indicate that marron production can be improved using stable pelleted diets in both intensive and semi-intensive culture. 相似文献
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A physical map of the 1-gigabase bread wheat chromosome 3B 总被引:2,自引:0,他引:2
Paux E Sourdille P Salse J Saintenac C Choulet F Leroy P Korol A Michalak M Kianian S Spielmeyer W Lagudah E Somers D Kilian A Alaux M Vautrin S Bergès H Eversole K Appels R Safar J Simkova H Dolezel J Bernard M Feuillet C 《Science (New York, N.Y.)》2008,322(5898):101-104
As the staple food for 35% of the world's population, wheat is one of the most important crop species. To date, sequence-based tools to accelerate wheat improvement are lacking. As part of the international effort to sequence the 17-billion-base-pair hexaploid bread wheat genome (2n = 6x = 42 chromosomes), we constructed a bacterial artificial chromosome (BAC)-based integrated physical map of the largest chromosome, 3B, that alone is 995 megabases. A chromosome-specific BAC library was used to assemble 82% of the chromosome into 1036 contigs that were anchored with 1443 molecular markers, providing a major resource for genetic and genomic studies. This physical map establishes a template for the remaining wheat chromosomes and demonstrates the feasibility of constructing physical maps in large, complex, polyploid genomes with a chromosome-based approach. 相似文献