91 resultados para Acanthaceae


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Bd. 1, Hälfte 1 u. 2 in einem Digitalisat

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Von G. Lindau

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Aconophora compressa (Hemiptera: Membracidae), a biological control agent introduced against the weed Lantana camara (Verbenaceae) in Australia, has since been observed on several non-target plant species, including native mangrove Avicennia marina (Acanthaceae). In this study we evaluated the suitability of two native mangroves, A. marina and Aegiceras corniculatum (Myrsinaceae), for the survival and development of A. compressa through no-choice field cage studies. The longevity of females was significantly higher on L. camara (57.7 ± 3.8 days) than on A. marina (43.3 ± 3.3 days) and A. corniculatum (45.7 ± 3.8 days). The proportion of females laying eggs was highest on L. camara (72%) followed by A. marina (36%) and A. corniculatum (17%). More egg batches per female were laid on L. camara than on A. marina and A. corniculatum. Though more nymphs per shoot emerged on L. camara (29.9 ± 2.8) than on A. marina (13 ± 4.8) and A. corniculatum (10 ± 5.3), the number of nymphs that developed through to adults was not significantly different. The duration of nymphal development was longer on A. marina (67 ± 5.8 days) than on L. camara (48 ± 4 days) and A. corniculatum (43 ± 4.6 days). The results, which are in contrast to those from previous glasshouse and quarantine trials, provide evidence that A. compressa adults can survive, lay eggs and complete nymphal development on the two non-target native mangroves in the field under no-choice condition.

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Ethnopharmacological relevance: Malaria is a serious public health problem in the north-eastern region of India including Assam, in view of development of chloroquine resistant Plasmodium falciparum. There is need for alternative and affordable therapy. Aim of the study: This study was conducted to document indigenous knowledge, usage customs and practices of medicinal plant species traditionally used by the residents of Sonitpur district of Tezpur, Assam to treat malaria and its associated symptoms. Materials and methods:A total of 50 randomly selected sampling represented by male (38.76%) and female respondents (12.24%) were interviewed using a semi-structured questionnaire. Results: The present ethno-botanical survey revealed 22 species of plants belonging to 17 botanical families were reported to be used exclusively in this region for the treatment of malaria. Verbenaceae (three species), Menispermaceae (two species), and Acanthaceae (two species) botanical families represented the species that are most commonly cited in this survey work and the detailed use of plants has been collected and described. Conclusions: The most serious threat to the existing knowledge and practice on traditional medicinal plants included cultural change, particularly the influence of modernization and lack of interests shown by the next younger generations were the main problems reported by the informants during the field survey. Hence, the proper documentation of traditional medicinal plants being used as anti-malarial agents and related indigenous knowledge held by the tribal community is an important approach to control the spread of vector-borne diseases like malaria reported in this survey work. (C) 2010 Elsevier Ireland Ltd. All rights reserved.

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Durante la época de primera de 1995, se estableció un experimento de campo en la finca Buenos Aires, localizada en el municipio de la Concepción, departamento de Masaya, con el propósito de evaluar la influencia de siete leguminosas de cobertura en asocio en el cultivo de la pitahaya (Hylocereus undatus. Britton & Rose), como manejo de las malas hierbas y aporte de nutrientes al suelo a partir de la materia orgánica incorporada. El diseño experimental utilizado en el estudio fue un Bloque Completos al azar, con cuatro repeticiones.Los tratamientos en estudio fueron: Vigna radiata, Mucuna pruriens, Phaseolus vulgaris, Dolichos lablab, Canavalia ensiformis, Cajanus cajan (semilla gris y roja), y el tratamiento testigo, el cual representa el manejo tradicional en el control de las malezas de parte del productor. Los resultados indican que las especies de malezas más dominantes fueron plantas de la familia poaceae sobresaliendo Cenchrus brownü, Digitaria ciliaris y Eleusine indica. Melampodium divaricatum de la familia Asteraceae. Mollugo verticillata de la familia Aizoaceae. Chamaesyce hirta de la familia Euphorbiaceae. Tetramerium nervosum y Elytraria imbricata de la familia Acanthaceae. Las especies descritas anteriormente fueron las más abundantes y estuvieron presentes en la diversidad. Tanto en la abundancia de malezas como en cobertura de las leguminosas los mejores resultados se presentaron en los tratamientos Dolichos lablab y Mucuna pruriens, seguido de Cajanus cajan (Gandul semilla roja y semilla gris), y Canavalia ensiformis. Por último los tratamientos Vigna radiata, Phaseolus vulgaris y el testigo, registraron la mayor abundancia de malezas. Tanto en la diversidad como en biomasa los mejores resultados se obtuvieron en Dolichos lablab y Mucuna pruriens, seguidos de Canavalia ensiformis y Cajanus cajan (Gandul semilla gris), por último se encuentran Cajanus cajan (Gandul semilla rojo), Vigna radiata, Phaseolus vulgaris y el testigo. En cuanto al aporte de nutrientes a partir de las materia orgánica los mejores resultados se presentaron en los tratamientos Vigna radiata, Dolichos lablab, Mucuna pruriens Cajanus cajan (Gandul semilla rojo y semilla gris), seguido de Canavalia ensiformis y Phaseolus vulgaris. Por último el que menor cantidad de nutrientes aportó fue el tratamiento testigo. En relación a la biomasa de las leguminosas, los mejores resultados se obtuvieron en los tratamientos Canavalia ensiformis y Cajanus cajan (Gandul semilla gris), registrando el mayor peso seco, seguido de Mucuna pruriens, Cajanus cajan (Gandul semilla roja), y Dolichos lablab. En tanto los tratamientos Phaseolus vulgaris y Vigna radiata, registraron el menor peso seco entre las leguminosas. En cuanto al mayor número y longitud de brotes (vainas) por planta, los mejores resultados se presentaron en los tratamientos Vigna radiata, Canavalia ensiformis y Dolichos lablab, seguido de Mucuna pruriens, Phaseolus vulgaris y Cajanus cajan (Gandul semilla gris y roja). En tanto el tratamiento testigo registró el menor número y longitud de brotes (vainas) por planta. Con respecto al rendimiento (Frutos 1 ha), los mejores resultados se obtuvieron en el tratamiento Dolichos lablab, seguidos de Cajanus cajan (Gandul semilla roja), Mucuna pruriens y Vigna radiata, presentaron rendimientos similares, seguidos de Cajanus cajan (Gandul semilla gris), Canavalia ensiformis y Phaseolus vulgaris, en tanto el testigo presentó el más bajo rendimiento. En cuanto al análisis económico de los tratamientos en estudio, el de mejor rentabilidad resultó ser Dolichos lablab, dado que ofrece el más alto beneficio neto, pese a ser uno de los tratamientos en que los costos fueron los más altos, además en éste tratamiento se obtuvo el mejor rendimiento de frutos.

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本文对苦苣苔科的3族8属10种植物进行了比较胚胎学研究,得出该科植物的基本胚胎学特征是: 花药具4个小孢子囊,当花药达到成熟期时,每—侧的两个小孢子囊由于隔壁的消失而连通。药壁由1层表皮,1层药室内壁,12层中层和1层绒毡层组成。花药壁的发育属双子叶类型,表皮细胞宿存,药室内壁在小孢子母细胞分裂成四分体后即开始纤维状加厚,到花药发育至成熟时期,药室内壁径向延长并由内切向壁向外和向上发生带状的加厚,但在同侧的两个小孢子囊的连接处并不发生纤维状加厚,以利于花药的开裂。中层细胞在小孢子母细胞分裂前即受到挤压,到发育后期被挤扁,.在成熟花药壁上只残留—些痕迹。有些种类中层细胞不退化,与药室内壁一样纤维状加厚。绒毡层初时为单核,在小孢子母细胞终变期分裂成双核,而当单核小孢子形成后,绒毡层细胞的两核可融合成单核,随后便解体。绒毡层为分泌型,在四分体分离成小孢子以后向药室内分泌乌氏体。在小孢子母细胞分裂前,细胞周围有大量的胼胝质出现。胞质纷裂为同时型。具四面体型的四分体。散粉时花粉具二细胞。 胚珠倒生,单珠被,薄珠心,珠被内无维管组织。珠心表皮下的—层细胞发育成为孢原细胞并直接起大孢子母细胞的功能,其胞质分裂伴随着减数分裂形成—直列式四分体。四分体珠孔端三个大孢子受挤压退化,合点端的功能大孢子进—步发育,经三次分裂形成蓼型胚囊。成熟胚囊的珠孔端部分圆形,合点端细长,如容量瓶状。胚囊内具—个由两个助细胞和—个卵细胞组成的卵器、两个极核和三个反足细胞。助细胞在花粉管通过珠孔进入胚囊后退化。极核在受精前不久融合,反足细胞形成后不久便退化。珠孔端的珠心细胞在功能大孢子发育后被挤压退化,也有的种类突出珠孔形成珠心喙,而合点端部分珠被最内的—层细胞则进—步发育,细胞质变浓,核体积增大,围绕胚囊的合点端细长部形成珠被绒毡层,此结构由胚囊形成到种子成熟—直存在,其中有丰富的内含物。 珠孔受精。胚乳发育为细胞型,种子成熟时几乎完全被胚吸收。合点端发育出具2核单胞的侵入性吸器,直达表皮。珠孔端吸器具2细胞。两种吸器的形态因种属不同而有很大差异。胚胎发生属柳叶菜型。 比较和分析表明,苦苣苔科的胚胎学特征与玄参科(Scrophujariaccae)、列当科(Orobanchaceae)和爵床科(Acanthaceae)较为相似,反映出这几个科在系统关系上比较接近。苦苣苔科族级分类群之间的胚胎学特征有一定的差异,但族内各属种的胚胎学特征差异较小,发育类型尤其是早期的形成过程非常相似。本文研究涉及的分类群在花药壁层的结构、反足细胞退化和极核融合韵时期、胚形成与胚乳发育的相对时间、吸器的有无及其形态等方面有所不同。 本文同时对苦苣苔科3族23属72种花粉,其中包括长蒴苣苔族(Trib. Didymocarpeae)16属56种、芒毛苣苔族(Trib. Trichosporeae)4属12种及尖舌苣苔族( Trib. Klugieae)3属4种,进行了扫描电镜观察。对族下各属种的形态特征作了详细的描述,每种花粉从极面观、赤道面观及局部放大三个侧面照相记录。以族为基本类群,对其中的各属的花粉形态结合系统学特征进行了讨论。 由此研究得出苦苣苔科植物花粉的基本特征是:所有研究属种的花粉均具三拟孔沟,拟孔极不明显。形状为近扁球形、圆球形、近长球形和长球形,极面观圆形、近圆形、近三角形和三裂圆形,赤道面观为圆形、近圆形、椭圆形和长圆形,不同材料各有差异,但在属内水平上基本—致。各属植物在花粉沟的形态和表面纹饰上有一定的区别。 在长蒴苣苔族中,本文对雇柱苣苔属(Chirita Buch.-Ham.ex D.Don)花粉进行了着重研究。结果表明:唇柱苣苔属在组内各种的花粉形态具有明显的相似性,但在组之间则有较大的差异。对本族其它各属的研究结果则充分表明各属花粉的形态特征有明显差别,可以从花粉形状、大小、沟的构造、沟膜的特点及表面纹饰等方面加以区分 在芒毛苣苔族中,紫花苣苔(Loxostigma griffithii)花粉沟膜表面残留着网状的覆盖层( tectum),这种覆盖层可能代表—种较原始的性状。.在芒毛苣苔属’( Aeschynanthu8)中,花冠的檐部通常呈现不明显二唇形的显苞芒毛苣苔组(Sect.Haplotrichum)和大花芒毛苣苔组(Sect. Diplotrichum)的花粉粒较小,而花冠的檐部明显二属形的黄杨叶芒毛苣苔组(Sect. hlicrotrichium)、小齿芒毛苣苔组(Sect. Xanthanthos)以及全尊芒毛苣苔组(Sect.Aeschynanthus)的花粉粒较大。因此,花冠檐部的结构与花粉粒的大小表现出—定的相关性.在尖舌苣苔族中,异叶苣苔属( Whytokia)和尖舌苣苔属(Rhynchoglossum)的花粉沟较短,后者和十字苣苔属( Stauranthera)的沟膜表面具有密集或稀疏的颗粒状突起。河口异叶苣苔( Whytokia hekouensis)花粉沟的分化不明显,其沟膜上残留着网状的覆盖层可能代表着—种较原始的性状。具聚伞花序的盾座苣苔属( Epithema)和圆果苣苔属( Gyrogyne),其花粉沟界极区及其沟间区呈皱波状(apocolpia and mesocolpia rugulate),代表另一种演化方向。根据本文研究结果,并参考国内外有关报道,分别提出了芒毛苣苔族和尖舌苣苔族的以花粉特征为依据的分属检索表。

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A new species of Acantbaceae, Staurogyne rubescens, is described and illustrated. It is endemic to the Brazilian moist forests on the eastern range of mountains named Serra do Mar and is thus far known only from the states of Rio de Janeiro and São Paulo. Staurogyne rubescens can be distinguished by its lax terminal racemes, with bracts and bracteoles that are foliaceous, and the flowers that have a pink calyx and red corolla. Staurogyne itatiaiae (Wawra) Leonard also has red flowers and occurs in the highlands of the Atlantic rain forest. The distinguishing characters for these two species are presented in tabular format.

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Pollen and stable carbon (d13C) and hydrogen (dD) isotope ratios of terrestrial plant wax from the South Atlantic sediment core, ODP Site 1085, is used to reconstruct Miocene to Pliocene changes of vegetation and rainfall regime of western southern Africa. Our results reveal changes in the relative amount of precipitation and indicate a shift of the main moisture source from the Atlantic to the Indian Ocean during the onset of a major aridification 8 Ma ago. We emphasise the importance of declining precipitation during the expansion of C4 and CAM (mainly succulent) vegetation in South Africa. We suggest that the C4 plant expansion resulted from an increased equator-pole temperature gradient caused by the initiation of strong Atlantic Meridional Overturning Circulation following the shoaling of the Central American Seaway during the Late Miocene.

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We present a high-resolution reconstruction of tropical palaeoenvironmental changes for the last deglacial transition (18 to 9 cal. kyr BP) based on integrated oceanic and terrestrial proxies from a Congo fan core. Pollen, grass cuticle, Pediastrum and dinoflagellate cyst fluxes, sedimentation rates and planktonic foraminiferal d18O ratios, uK37 sea-surface temperature and alkane/alkenone ratio data highlight a series of abrupt changes in Congo River palaeodischarge. A major discharge pulse is registered at around 13.0 cal. kyr BP which we attribute to latitudinal migration of the Intertropical Convergence Zone (ITCZ) during deglaciation. The data indicate abrupt and short-lived changes in the equatorial precipitation regime within a system of monsoonal dynamics forced by precessional cycles. The phases of enhanced Congo discharge stimulated river-induced upwelling and enhanced productivity in the adjacent ocean.

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Pollen analytical studies of the ODP Site 720 cores revealed the wide development of the coniferous forest, which mainly composed by Pinus, Picea, Abies and Cedrus deodara, along the Indus river since the early Pleistocene.

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Some samples from DSDP Holes 530A and 532 were analyzed for their fossil pollen content. The sites are located in the southeastern corner of the Angola Basin, about 200 km west of the present coastline. Fossil pollen assemblages of Holocene to Miocene age were compared with present-day pollen deposition in the arid Namib sand sea. The strong resemblance of all the pollen spectra indicates that very arid conditions existed in the coastal region of Namibia in Quaternary and Pliocene times. These data are in agreement with the late Miocene origin of the coastal aridity and with the conception that upwelling of cold water was responsible for these desert conditions.

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ODP Site 1078 situated under the coast of Angola provides the first record of the vegetation history for Angola. The upper 11 m of the core covers the past 30 thousand years, which has been analysed palynologically in decadal to centennial resolution. Alkenone sea surface temperature estimates were analysed in centennial resolution. We studied sea surface temperatures and vegetation development during full glacial, deglacial, and interglacial conditions. During the glacial the vegetation in Angola was very open consisting of grass and heath lands, deserts and semi-deserts, which suggests a cool and dry climate. A change to warmer and more humid conditions is indicated by forest expansion starting in step with the earliest temperature rise in Antarctica, 22 thousand years ago. We infer that around the period of Heinrich Event 1, a northward excursion of the Angola Benguela Front and the Congo Air Boundary resulted in cool sea surface temperatures but rain forest remained present in the northern lowlands of Angola. Rain forest and dry forest area increase 15 thousand years ago. During the Holocene, dry forests and Miombo woodlands expanded. Also in Angola globally recognised climate changes at 8 thousand and 4 thousand years ago had an impact on the vegetation. During the past 2 thousand years, savannah vegetation became dominant.

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Pliocene vegetation dynamics and climate variability in West Africa have been investigated through pollen and XRF-scanning records obtained from sediment cores of ODP Site 659 (18°N, 21°W). The comparison between total pollen accumulation rates and Ti/Ca ratios, which is strongly correlated with the dust input at the site, showed elevated aeolian transport of pollen during dusty periods. Comparison of the pollen records of ODP Site 659 and the nearby Site 658 resulted in a robust reconstruction of West African vegetation change since the Late Pliocene. Between 3.6 and 3.0 Ma the savannah in West Africa differed in composition from its modern counterpart and was richer in Asteraceae, in particular of the Tribus Cichorieae. Between 3.24 and 3.20 Ma a stable wet period is inferred from the Fe/K ratios, which could stand for a narrower and better specified mid-Pliocene (mid-Piacenzian) warm time slice. The northward extension of woodland and savannah, albeit fluctuating, was generally greater in the Pliocene. NE trade wind vigour increased intermittently around 2.7 and 2.6 Ma, and more or less permanently since 2.5 Ma, as inferred from increased pollen concentrations of trade wind indicators (Ephedra, Artemisia, Pinus). Our findings link the NE trade wind development with the intensification of the Northern Hemisphere glaciations (iNHG). Prior to the iNHG, little or no systematic relation could be found between sea surface temperatures of the North Atlantic with aridity and dust in West Africa.

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The distribution of pollen in marine sediments is used to record vegetation change on the continent. Generally, a good latitudinal correspondence exists between the distribution patterns of pollen in the marine surface sediments and the occurrence of the source plants on the adjacent continent. To investigate land-sea interactions during deglaciation, we compare proxies for continental (pollen assemblages) and marine conditions (alkenone-derived sea surface temperatures) of two high-resolution, radiocarbon-dated sedimentary records from the tropical southeast Atlantic. The southern site is located West of the Cunene River mouth; the northern site is located West of the Angolan Huambe Mountains. It is inferred that the vegetation in Angola developed from Afroalpine and open savannah during the last Glacial maximum (LGM) via Afromontane Podocarpus forest during Heinrich Event 1 (H1), to an early increase of lowland forest after 14.5 ka. The vegetation record indicates dry and cold conditions during the LGM, cool and wet conditions during H1 and a gradual rise in temperature starting well before the Younger Dryas (YD) period. Terrestrial and oceanic climate developments seem largely running parallel, in contrast to the situation ca. 5° further South, where marine and terrestrial developments diverge during the YD. The cool and wet conditions in tropical West Africa, South of the equator, during H1 suggest that low-latitude insolation variation is more important than the slowdown of the thermohaline circulation for the climate in tropical Africa.