共查询到19条相似文献，搜索用时 156 毫秒
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蕨类植物又称羊齿植物,是地球上现存最早的维管植物,许多蕨类植物的形态优美,是著名的观叶植物,如铁线蕨、巢蕨属、鹿角蕨属、荚果蕨等具有极高的观赏价值.自然界中千姿百态的蕨类植物,除了正常的孢子生殖外,蕨类植物的根、根状茎和叶,都能依靠产生的无性孢芽和顶端分生组织产生新的植株,但对不同类型的观赏蕨类植物应采取不同的无性繁殖方法. 相似文献
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概述了包括赤霉素、成精子囊素、乙烯、细胞分裂素在内的植物激素、培养密度、营养条件、光照条件等环境因素以及配子体自身条件对蕨类植物性别决定的影响,并结合近年来性别决定调控机制在遗传学以及分子生物学方面取得的研究进展,综述了海金沙（Lygodium japonicum）中成精子囊素通过时空分离的赤霉素生物合成途径调控性别的分子机制、水蕨（Ceratopteris richardii）中性别决定遗传学和分子模型以及与性别决定相关的MADS-box基因,指出蕨类植物性别决定调控机制研究需要解决的一系列问题以及未来蕨类植物性别决定的研究方向。 相似文献
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南洋杉组织培养与快速繁殖研究罗建勋（四川省林业科学研究院林业研究所，成都６１００８１）关键词南洋杉；组织培养；快速繁殖ＴｉｓｕｅＣｕｌｔｕｒｅａｎｄＲａｐｉｄＰｒｏｐａｇａｔｉｏｎｏｆＡｒａｕｃａｒｉａｈｅｔｅｒｐｈｙｌａＬｕｏＪｉａｎｘｕｎ（Ｔｈｅ... 相似文献
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蕨类植物,又称羊齿植物,是高等植物中比较低级而又不开花的一个类群,素有"无花之美"之称。本文主要论述了蕨类植物的栽培繁殖技术以及在园林景观中的应用。 相似文献
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脱毒冬枣系采用茎尖组织培养和热处理脱除枣疯病毒（ＭＬＯ）的晚熟鲜食枣品种。具有果大（平均单果重３２ｇ）、皮薄、肉厚、质细、多汁、无渣、甜味浓等特点，品质极佳。植株生长健壮，结果早、产量高，市场前景广阔。但作为鲜食品种栽培，目前生产上仍沿用传统的稀植方... 相似文献
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甜菜M14品系在细胞胚胎学和遗传学特征上具有鲜明的无融合生殖现象。为了寻找在这一特殊的生殖过程中的相关基因及其调控作用．实验通过同源克隆及cDNA末端快速扩增（RACE）的方法,首次从甜菜M14品系中克隆了与生殖相关的基因ByCK2（Beta vulgaris casein kinase2）的全长cDNA序列．长度为1501bp,开放阅读框为1002bp,编码333个氨基酸。根据氨基酸序列计算蛋白分子量为39．28kDa,pI=8．16。同源比对表明,ByCK2与烟草CK2（Ge．nBankNo．A1437635）的相似度为64.22％,与百合CK2（GenBankNo．AF517838）的相似度为65．18％。通过细胞内定位分析．ByCK2所编码的蛋白主要存在于细胞核中。 相似文献
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本文通过野外调查查阅文档资料,总结出韶关野生蕨类共362种,对野生蕨类的形态特征、配置方式进行分析,对其在韶关园林应用中的前景作了展望。 相似文献
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在对巴尔鲁克山自然保护区进行多次综合科学考察并文献查阅与标本鉴定基础上,系统的对该区生物物种进行了分类与统计.结果表明:自然保护区内分布的植物有81科、444属、1 178种,其中蕨类植物15种,分属于7科9属；裸子植物7种,分属于3科4属；被子植物1 136种,分属于71科431属；主要植被类型有63个群系；保护区分布有兽类3目7科19种,鸟类16目42科149种,昆虫纲有14目、114科、426属、585种.最后,针对巴尔鲁克山自然保护区的现状和存在的问题,提出相应的保护对策. 相似文献
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Ann Van Herzele Eva M. De Clercq Torsten Wiedemann 《Urban Forestry & Urban Greening》2005,3(3-4):177-188
Current strategies for creating new woodlands in the urban periphery aim to provide as many people as possible with a recreational green space close to where they live. When taking a socially inclusive approach, however, this also involves a number of ‘distributional’ questions. These refer to the kind of people likely to benefit the most from such a plan: urban or suburban residents, low or high-income groups, and so forth. This article presents a GIS-based working method aimed at exploring different options for urban woodland proposals with regard to their positioning in relation to residential areas, as well as the socio-spatial characteristics of those areas. The example of seven possible locations for a new ‘peri-urban forest’ in Antwerp, Belgium was used to demonstrate the method's potential to address relevant questions in socially inclusive planning and hence, to improve strategic planning for new urban woodlands. 相似文献
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Pulmonary hypertension induced by high pulmonary blood flow involves a variety of complex mechanisms, including endothelial damage, pulmonary artery smooth muscle relaxation-contraction disorder and vascular remodeling. Besides, the factor of ion channels in pulmonary artery smooth muscle cells is also highly correlated to vasoconstriction. In recent years, many studies have shown that activation of Ca2+-activated Cl- channels is responsible for the membrane depolarization of pulmonary artery smooth muscle cells, and plays an important role in the regulation of vascular tone and vasoconstriction. This article reviews the biophysical and pharmacological characteristics of Ca2+-activated Cl- channels as well as the influence of Ca2+-activated Cl- channels in high pulmonary blood flow-induced pulmonary hypertension. 相似文献
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Robert Gilmore Pontius Jr. Anna J. Versluis Nicholas R. Malizia 《Landscape Ecology》2006,21(7):1151-1166
This article presents a method to estimate and to visualize the certainty of land change models as they extrapolate beyond
the time interval for which empirical data exist. The method to project the certainty relies on measurements of model performance
during a validation run with historic data and on the assumption that the model’s accuracy approaches randomness as it predicts
farther into the future. A land change model typically predicts each pixel as exactly one category for each year. This article
presents a technique to convert those predictions into conditional probabilities. As an example, we use the model Geomod to
extrapolate forest change over a century for the Plum Island Ecosystems, which is a Long Term Ecological Research site of
the United States’ National Science Foundation. Geomod uses calibration information between 1971 and 1985 in order to predict
the changes from 1985 to 1999, at which point the validation procedure measures the model’s predictive accuracy. Then the
model is re-calibrated with information from 1985 to 1999 in order to extrapolate into the future, assuming a business as
usual scenario. As time progresses, the expected accuracy approaches 0.5, which is the probability at which the model’s prediction
is as accurate as a random prediction, since the application involves two categories. The extrapolated accuracy of the prediction
for the entire study area in the year 2097 is 68%. The method is designed to work with any number of categories so it can
be used with a variety of land change models. 相似文献
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内蒙古大兴安岭林区蕨类植物资源及其开发利用 总被引：1，自引：0，他引：1
内蒙古大兴安岭林区地域辽阔、森林繁茂、雨量充沛,为蕨类植物的生长提供了较为适宜的条件。本林区共有蕨类植物52种（含6变种、1变型）,分属于15科、24属。以林下、林缘分布为主;有土生种类52种,占总种数的61．54％;石生蕨类17种,占总种数52．69％;水生种类5种,占总种数5．77％。在食用、药用、观赏、土壤类型指示种类等方面资源丰富。资源利用方面蕨菜资源破坏严重,政府正确引导的同时,应探索实施人工种植;药用蕨类虽然种类丰富,但缺乏相关研究和了解,未形成规模利用;观赏蕨类和土壤指示蕨类,应加强相关研究与开发利用。 相似文献