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近几十年来我国成功的从国外引进多种金合欢树种，并在广东、海南、福建、广西等地推广种植。总结这些树种的引种地和原产地，并从微型繁殖、器官发生、体细胞胚胎发生3个方面总结了近年来在我国引种成功的金合欢树种离体繁殖的研究进展，这将对我国金合欢树种的进一步研究及其推广种植具有重要意义。 相似文献
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为了丰富祁连山东段林区天祝县境内造林绿化树种和准确区分相似树种,研究了圆柏属6个树种,即祁连圆柏、垂枝圆柏、大果圆柏、塔枝圆柏、密枝圆柏和方枝圆柏的适应特性、生长特性和形态特性。结果表明:不同树种分布海拔、天然林集中分布地,种子发芽率、树高、冠幅和根长都存在差异,但鉴别树种时应以叶片、枝条和树形等特征为主。此外,应从树种的原产地和起源地引种和调运苗木,引种试验由小面积到大面积示范推广。 相似文献
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前言
所谓树种引种,即是将当地没有的经济价值高的树种由外地（或野生）引来在当地栽培,它包括木材、经济、药用、化学等诸方面的树种。在这个过程中,必然会出现两种情况：一种是原产地与引种的生长环境条件基本吻合,树木并不需要改变它的遗传特性,即能适应新的环境条件,并顺利生长和发育; 相似文献
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桉树原产地为澳大利亚,是我国为了有效提高绿化面积所引进的树种之一,目前主要种植在我国四川、广西、云南等南部几省,是我国速生丰产林的主要树种之一.虽然该树种对我国的生态保护具有重要意义,但是由于管理不当等因素,导致桉树病虫害的种类不断增加.当下速丰桉主要的病害有8种,主要的虫害有11种.因此,相关部门应有效开展病虫害防治... 相似文献
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黑木相思树原产于澳大利亚,是一种具有较高经济价值和生态效益的树种。我国华南地区气候和土壤与黑木相思树的原产地相近,适宜黑木相思树的生长,是我国近年来引进的树种之一,主要用于速生林、园林绿化等方面,具有生长速度快、改善土壤的作用。本文主要探讨黑木相思树的种植技术,提高黑木相思树的生活率。 相似文献
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湖南优良乡土树种的引种栽培研究 总被引：3，自引：0，他引：3
在对湖南省优良乡土树各原产地进行反复调查研究，进行多年引种栽培试验的基础上，提出优良，乡土树种引种栽培的方法，步骤以及技术要点，根据引种试验中各树种的生长情况以及注重树种的经济价值，观赏价值，生态效益的引种原则，筛选出了４０余种能适应本省不同立地条件的优良乡土树种，并进行中试或在生产中推广应用，结果表明，这些树种中，有的可作用材树种，有的可作经济林树种，有的可作园林和绿化树种，并提出了各树种的推广 相似文献
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Average species durations were estimated for 131 commonly occurring modern species. The duration of species occurring at depths of less than 200 meters is 16 million years, while for those at greater than 200 meters and at all depths it is 25 to 26 million years. Species (less than 200 meters) distributed from Florida to Newfoundland and from Florida to Cape Hatteras have about the same durations (18 to 20 million years). The duration for species restricted to north of Cape Hatteras is only 7 million years. The data suggest that evolutionary rates are greater in shallower than in deeper depths and greatest in the shallower northern area. 相似文献
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Six sympatric species of 5-million-year-old (late Hemphillian) horses from Florida existed during a time of major global change and extinction in terrestrial ecosystems. Traditionally, these horses were interpreted to have fed on abrasive grasses because of their high-crowned teeth. However, carbon isotopic and tooth microwear data indicate that these horses were not all C4 grazers but also included mixed feeders and C3 browsers. The late Hemphillian Florida sister species of the modern genus Equus was principally a browser, unlike the grazing diet of modern equids. Late Hemphillian horse extinctions in Florida involved two grazing and one browsing species. 相似文献
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A deposit of fossil seabirds from the late Pliocene of Florida includes more than 130 skeletons of an extinct cormorant that is related phylogenetically to Recent species currently restricted to the eastern north Pacific. Evidence suggests the birds died in a single catastrophic event, perhaps a red tide. The fossil cormorant, along with other extinct seabirds and marine mammals, supports molluscan evidence for cold-water upwelling along the Florida Gulf Coast during the Pliocene. A decline in species richness of marine vertebrates throughout the Pliocene of Florida coincides with cessation of upwelling after emergences of the Panamanian Land Bridge. 相似文献
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应用单个体培养和群体培养方法,在25℃条件下,对萼花臂尾轮虫Brachionus calyciflorus南京品系(NJ)和美国佛罗里达品系(FL)的幼体发育时间、胚胎发育时间、繁殖量、种群增长参数及品系间、品系内受精率进行了研究.结果表明:萼花臂尾轮虫FL品系与NJ品系的幼体发育时间、第一个幼体孵出时间和繁殖量之间均无显著性差异(P＞0.05),而NJ品系的胚胎发育时间比FL品系显著缩短6.9％(P＜0.05); NJ品系的净生殖率(R0)、内禀增长率(rm)、世代时间(T)和生命期望(e0)均显著大于FL品系(P＜0.05);萼花臂尾轮虫FL和NJ品系雌雄交配试验结果表明,两品系间的受精率低于各自品系内交配的受精率.本研究表明,南京品系和佛罗里达品系萼花臂尾轮虫的发育和种群增长参数存在显著差异,但两品系之间不存在完全的生殖隔离,未形成姐妹种. 相似文献
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Two whales were observed closely for an hour off Sarasota, Florida, by residents who provided observations of structural details which identify only the right whale, Eubalaena glacialis, a temperate and subpolar species previously known to range to the Florida east coast, but not to enter the Gulf of Mexico. 相似文献
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Pine plantation management did not initially convert natural forests to monocultures; rather it increased plant species richness and diversity. During a 5-year study of two natural watersheds in Florida that were converted to plantations, woody species diminished, but herbaceous species increased. Number of plant species on permanent transects and plots increased. Diversity of cover, frequency, and biomass did not diminish or else increased after harvest. 相似文献
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Annual and interannual variations in the Florida Current, Caribbean, and subtropical Atlantic are investigated with the use of historical sea level differences and wind field data. Observational and model evidence suggests that the seasonal transport cycle of the Florida Current is locally forced, either upstream in the Caribbean or downstream over topography. Although at seasonal and shorter periods sea level or bottom pressure fluctuations on the left side of the Florida Current contribute almost all of the variance of sea level difference across the Florida Straits and hence transport, this relation does not seem to apply at interannual time scales. Using results from the Subtropical Atlantic Climate Studies, it is estimated from historical sea level data that interannual transport fluctuations of the Florida Current are only of order 1 x 10(6) cubic meters per second. Interannual fluctuations in the 2- to 3-year period range in the Florida Straits seem to be correlated with sea level differences across the Caribbean and the subtropical Atlantic but not with Sverdrup transport fluctuations in the subtropical Atlantic. 相似文献
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2011年7月16～22日,在贵州省佛顶山自然保护区进行蛇类动物资源调查时,共采集到12条标本,经鉴定为8种,隶属游蛇科的8个属。其中,龙胜小头蛇(Oligodon lungshenensis)和山溪后棱蛇(Opisthotropis latouchii)为佛顶山蛇类新纪录。结合以往文献记载,现已发现佛顶山蛇类共29种,隶属3科、20属。佛顶山自然保护区蛇类比梵净山国家级自然保护区少4种,这2个保护区蛇类动物区系具有明显的东洋界特色,佛顶山蛇类动物区系组成以东洋界华南区物种(占种数的17.24%)以及华中区和华南区共有种(占种数的58.62%)为主,而梵净山蛇类动物区系组成以东洋界华中区物种(占种数的18.18%)以及华中区和华南区共有种(占种数的57.58%)为主。 相似文献
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根据剑角蝗科（Acrididae）在我国各动物地理区的种类组成和区系特点,发现华北区和华中区的区系特点不明显,前者为南北成分的混交区,后者为特有种可跨区分布,这与蝗虫有明显的区域和地带分布的特点不相符。 相似文献
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宁夏已知有金龟子昆虫9科36属55种,以此作为研究对象讨论了该类昆虫在宁夏的区系组成和分布特点。在区系特征上,蒙新区成分有47种（占85.4%）,华北成分有42种（占76.3%）,青藏成分有18种（占32.7%）,东北成分有37种（占67.3%）,西南和华南成分分别为17种（各占30.9%）,华中成分20种（占36.4%）。结果表明,宁夏金龟子在区系组成上以蒙新区、华北区为主,东北区略次之。在区域地理分布上,六盘山区34种（占61.8%）,荒漠半荒漠区有38种（占69.1%）,黄土高原区有27种（占49.1%）。 相似文献