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对毕节学院植物标本室(BJ)韭菜坪及其邻近地区相关蕨类植物标本进行整理、鉴定。结果表明:韭菜坪及其邻近地区共有蕨类植物36科79属239种;其中,天坑耳蕨(Polystichum tiankengicola)、韭菜坪耳蕨(P.jiucaipingense)、吞天井耳蕨(P.puteicola)、天坑鳞毛蕨(Dryopteris jiucaipingensis)和贵州岩蕨(Woodsia guizhouensis)为近年来的新发布种;根据统计,该地区蕨类植物的优势科分别是鳞毛蕨科Pryopteridaceae(5属51种),蹄盖蕨科Athyriaceae(10属34种)和水龙骨科Polypodiaceae(11属31种);该地区的优势属分别是鳞毛蕨属(Dryopteris)21种,耳蕨属(Polystichum)21种,蹄盖蕨属(Athyrium)16种。本地区蕨类植物科和属的分布热带性成分较高,分别有15科45属,占本区蕨类植物总科数的71.43%(世界分布的科除外)和总属数的67.16%(世界分布属数除外);该区蕨类植物种的分布温带性成分有174种,占本区蕨类植物总种数的72.80%;同时,该地区蕨类植物种的中国特有成分较高,共有36种,占全部种数的15.06%,是现代中国蕨类的分布和分化中心之一。 相似文献
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冬青属(Ilex)是冬青科在我国分布的唯一属,该属植物主产于长江流域以南各省及台湾。目前除冬青(I.purpurea)、枸骨(I.cornuta)等少数种类外被普遍栽培外,大部分富有观赏特性的种类仍处于野生状态。笔者近年来对福建省冬青属野生观果植物进行了调查引种,现介绍以下7个常见类: 相似文献
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铁线蕨属(Adiantum L.)隶属于铁线蕨科(Adiantaceae),属内植物为多年生中小型蕨类,适应性强,分布广泛。本属有200多种植物,中国现已发现30余种。铁线蕨属植物多数具有良好的抗菌、抗癌、抗氧化等药理作用,在临床上有诸多应用。此外,铁线蕨属植物外形美观,多用于室内盆栽和园林设计,具有良好的观赏价值。为了探究出更有效地保护及繁殖方法以及更高效地利用铁线蕨属植物的观赏及药用价值,本综述就繁殖技术、形态特征、园林及医药应用等方面对该属植物的研究进展进行了概述,以期为后续的栽培管理及开发利用提供参考。 相似文献
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氮肥水平对强筋小麦产量和氮素利用的影响 总被引：1，自引：1，他引：0
为明确强筋小麦产量与效率相协同的最优施氮量,试验选用‘济麦20’和‘洲元9369’ 2个优质强筋小麦品种为试验材料,设置0、120、180、240、300 kg N/hm 2等5个施氮水平,用烘干法和凯氏定氮法分别测定小麦成熟期干物质量积累和含氮量,用以计算小麦氮素积累及氮素利用相关指标。结果表明,随氮肥投入量的增加,小麦产量呈现先升高后降低的变化趋势,其中‘济麦20’在N180和N240下达最高产量7.28 t/hm 2和7.26 t/hm 2,其较高的产量主要源于相对平衡的产量构成因素以及较高的干物质积累量（平均18.54 t/hm 2）;‘洲元9369’在N180下产量最高达7.75 t/hm 2,其较高的产量主要源于较高的单位面积穗数(970.65万/hm 2)、穗粒数（30.83粒）、较高的干物质积累量(20.77 t/hm 2)和收获指数(37.33%)。虽然氮肥偏生产力随着氮肥施用量的增加逐渐下降,但两品种的氮肥回收效率、氮肥农学利用率和氮肥生理利用效率均可在N180条件下达到最高值,其中,‘济麦20’最高值分别为62.67%、5.71 kg/kg、9.11 kg/kg,‘洲元9369’的最高值分别为63.65%、7.33 kg/kg、11.55 kg/kg。综合产量水平和氮素利用相关指标,本区域强筋小麦生产中产量与氮素利用效率相协同的施氮量为180 kg/hm 2。 相似文献
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辽宁春季界限温度发生日期的预报方法研究 总被引：1，自引：1，他引：0
为了在春季气候预测工作中,尽可能准确地预测辽宁春季稳定通过5℃的日期,采用1961—2010年辽宁省53站逐日气温资料和NCEP/NCAR再分析的月平均位势高度场、海平面气压场资料以及由NOAA重构的月平均海温场资料,通过相关分析方法并开展物理因子的普查工作,寻找辽宁春季稳定通过5℃日期的影响因子,并利用多元线性回归方法建立预报方程。结果表明：1961—2010年辽宁春季气温稳定通过5℃日期随时间有提前出现的趋势;稳定通过5℃日期与2月北大西洋海温、1月西北太平洋海温、2月北极涛动、1月印度洋海温、10月阿留申低压强度和1月北大西洋涛动关系密切;建立的预报稳定通过5℃日期的多元线性回归方程具有显著意义。 相似文献
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David Stuligross 《Asia Pacific viewpoint》2008,49(1):83-97
Abstract: Jharkhand is at the centre of India's struggles to define ‘the environment’ and ‘economically relevant natural resources’. Although cultural labels are applied by leaders who seek influence in these struggles as well as by many of those people who listen, an ethnonational analytic frame does not help answer the questions: How, why and when has the political idea of environment changed in India? When and why has the Jharkhand movement chosen violent tactics? When and why has the Jharkhand statehood movement realised electoral success? Or, why was Jharkhand state formed? To address such questions, a long range historical‐institutional approach is much more fruitful. 相似文献
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YUAN Zheng-qiang 《保鲜与加工》2000,(5):107-110
This paper presents the class of high effective locations and its addition, subtraction, multiplication, division, involution and factorial by the object-oriented programming. 相似文献
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Fouad M. Basiouny 《Journal of Agronomy and Crop Science》1986,157(1):31-35
Sensitivity of different agronomic crops to UV-B radiation was studied under environmentally controlled conditions. UV-B radiation reduced plant height, fresh weight, dry weight and ash contents. The reduction varied among the different species tested. Narrow-leaved plants (mainly C4 ) were less sensitive to UV-B than broad-leaved plants (mainly C3 ). 相似文献
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The origin,evolution, cultivation,dissemination, and diversification of Asian and African rices 总被引：28，自引：0，他引：28
Te-Tzu Chang 《Euphytica》1976,25(1):425-441
Summary Available evidences drawn from biosystematics, evolutionary biology, biogeography, archaeology, history, anthropology, paleo-geology and paleo-meteorology are pooled to reconstruct the series of events that led to the cosmopolitan cultivation of the Asian cultivated rice (O. sativa) and the regionalized planting of the African cultigen (O. glaberrima) in West Africa. The genus Oryza originated in the Gondwanaland continents and, following the fracture of the supercontinent, became widely distributed in the humid tropics of Africa, South America, South and Southeast Asia, and Oceania. The two cultivated species have had a common progenitor in the distant past. Parallel and independent evolutionary processes occurred in Africa and in Asia, following the sequence of: wild perennialwild annualcultivated annual. The weed races also contributed to the differentiation of the cultivated annuals. The corresponding members of the above series are O. longistaminata
Chev. et Roehr., O. barthii
A. Chev., O. glaberrima
Steud., and the stapfii forms of O. glaberrima in Africa; O. rufipogon
Griff., O. nivara
Sharma et Shastry, O. sativa L., and the spontanea forms of O. sativa in Asia.The differentiation and diversification of the annuals in South Asia were accelerated by marked climatic changes following the last glacial age, dispersal of plants over latitude or altitude, human selection, and manipulation of the cultural environment.Cultivation of rice began in many parts of South and Southeast Asia, probably first in Ancient India. Cultural techniques such as puddling and transplanting were first developed in north and central China and later transmitted to Southeast Asia. Wetland culture preceded dryland culture in China, but in hilly areas of Southeast Asia, dryland cultivation is older than lowland culture. The planting method progressed from shifting cultivation to direct sowing in permanent fields, then to transplanting in bunded fields.Widespread dispersal of the Asian cultigen led to the formation of three eco-geographic races (Indica. Sinica or Japonica, and Javanica) and distinct cultural types in monsoon Asia (upland, lowland, and deep water). Varietal types changed readily within the span of a millenium, largely due to cultivators' preferences, socio-religious traditions, and population pressure. Genetic differentiation developed parallel to the ecologic diversification process.The African cultigen developed later than the Asian cultigen and has undergone less diversification. The wild races in South America and Oceania retain their primitive features mainly due to lack of cultivation pressure or dispersal.Both the African and Asian rices are still undergoing evolutionary changes at habitats where the wild, weed, and cultivated races co-exist. 相似文献