首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 125 毫秒
1.
报道了中国兰科植物一新记录种,扁茎禾叶兰Agrostophyllum planicaule (Wall.ex Lindl.) Rchb. f.。本种主要特点是茎扁平,柱头基部有2个牛角状突起,可与本属其他种明显区分开。  相似文献   

2.
斑叶兰的组织培养   总被引:1,自引:0,他引:1  
1 植物名称斑叶兰(Goodyera schlechtendalianaRchh.f.)。 2 材料类别 茎段。  相似文献   

3.
斑叶兰自然种群生物量生殖分配研究   总被引:7,自引:0,他引:7  
(1.井冈山学院生命科学学院,江西吉安343009;2.西南大学生命科学学院,重庆400715)斑叶兰开花前各构件的生物量在总生物量中所占比例具有明显差异,且在生境间具显著差异。在柳杉林中,茎构件所占比例显著高于其它构件的比例;其它生境中正常叶的比例显著高于同生境下其它构件的比例。花期,斑叶兰茎和叶构件所占比例最大,其中仅在灌丛中正常叶构件分配比例略大于其茎构件的,但二者差异不显著;生殖构件中,花瓣所占比例最大;除花托叶(p=0.002)外,其余生殖构件的分配比例在生境之间的差异均不显著;合蕊柱在各群落生境中的分配比例差异极小,几乎是恒定的。斑叶兰的生物量生殖分配表现出随分布群落演替阶段的提高而下降的趋势,即竹林>人工柳杉林>灌丛>混交林;其生殖分配在20·35%~28.90%之间,而以干重计算则为21.09%~31.80%之间,明显高于其它一些多年生植物的(0%~20%),而表现出一年生植物的生殖分配特性。  相似文献   

4.
1植物名称高斑叶兰[Goodyera procera(Ker- Gaw1.)Hook.]。2材料类别茎段。3培养条件(1)芽诱导培养基:MS 6-BA 0.5 mg·L~(-1)(单位下同) NAA 0.05;(2)增殖培养基:1/ 2 MS 6-BA 2.0 NAA 0.2 100 g·L~(-1)椰汁:(3)生根培养基:1/2Ms IBA 1.0 NAA 0.5 0.5 g·L~(-1)活性  相似文献   

5.
为了发掘我国小麦种质资源中具有禾谷镰孢菌茎基腐病(crown rot)抗性的材料,采用禾谷镰孢菌苗期接种试验的方法,研究了82份小麦种质对禾谷镰孢菌茎基腐病的抗性.结果表明,在鉴定的材料中没有发现高抗材料;中抗材料13份,占总数的15.8%,包括CI12633、红蚰子、FHB143、Tiszataj和紫秆子等;大多数材料为感病材料.值得注意的是不同小麦材料对禾谷镰孢菌赤霉病和茎基腐病具有不同的抗性水平,两种病害没有正相关性,暗示小麦茎基腐病和赤霉病的抗性机制可能不同,因此,需要广泛挖掘具有茎基腐病抗性的小麦资源.  相似文献   

6.
本文描述了兰科新种套叶兰Hippeophyllum sinicum S.C Chen et K.Y.Lang;同时讨论了台湾替代种宝岛套叶兰 H.pumilum的命名问题,并标定了该种的后选模式。  相似文献   

7.
报道了中国海南兰科无叶兰属植物一新记录种:小花无叶兰Aphyllorchis pallida Bl.,本种的主要特征是花小,直径小于1 cm,唇瓣分两部分,后唇具两个耳状物,前唇3裂。  相似文献   

8.
云南苞叶兰属一新种   总被引:2,自引:0,他引:2  
孟连苞叶兰 新种 图 1BrachycorythismenglianensisY .Y .Qian ,sp .nov.(Trib .Orchideae ,Subtrib .Orchidi nae) . Fig.1SpeciesaffinisB .galeandrae (Rchb .f.)Summerh .,sedfloribusalbisvelpallidepur pureis,sepalis 5 nerviis,intermedioangusteovatoveloblongo ,1 2~ 1 3mmlongo ,4~ 4 .5mmla to ,eisl…  相似文献   

9.
浙江兰科新记录属——对叶兰属   总被引:1,自引:0,他引:1  
在对浙江景宁县望东垟高山湿地自然保护区植物资源考察中,发现了浙江兰科Orchidaceae新地理分布属、种--对叶兰属Listera R. Br.日本对叶兰Listera japonica,引证标本存于浙江农林大学植物标本馆(ZJFC)。  相似文献   

10.
报道了中国大陆对叶兰属Listera植物一新记录-日本对叶兰Listera japonica Bl.及其生境。  相似文献   

11.
The Precautionary Principle is in sharp political focus today because (1) the nature of scientific uncertainty is changing and (2) there is increasing pressure to base governmental action on more “rational” schemes, such as cost-benefit analysis and quantitative risk assessment, the former being an embodiment of ‘rational choice theory’ promoted by the Chicago school of law and economics. The Precautionary Principle has been criticized as being both too vague and too arbitrary to form a basis for rational decision making. The assumption underlying this criticism is that any scheme not based on cost-benefit analysis and risk assessment is both irrational and without secure foundation in either science or economics. This paper contests that view and makes explicit the rational tenets of the Precautionary Principle within an analytical framework as rigorous as uncertainties permit, and one that mirrors democratic values embodied in regulatory, compensatory, and common law. Unlike other formulations that reject risk assessment, this paper argues that risk assessment can be used within the formalism of tradeoff analysis—a more appropriate alternative to traditional cost-benefit analysis and one that satisfies the need for well-grounded public policy decision making. This paper will argue that the precautionary approach is the most appropriate basis for policy, even when large uncertainties do not exist, especially where the fairness of the distributions of costs and benefits of hazardous activities and products are a concern. Furthermore, it will offer an approach to making decisions within an analytic framework, based on equity and justice, to replace the economic paradigm of utilitarian cost-benefit analysis.  相似文献   

12.
We report 20 new species records for the Coleoptera fauna in New Brunswick, Canada, five of which are new records for the Maritime provinces, including one species that is new for Canada. One species of Kateretidae, Kateretes pusillus (Thunberg) is newly recorded for New Brunswick and the Maritime provinces. Stelidota octomaculata (Say), Phenolia grossa (Fabricius), andCryptarcha strigatula Parsons of the family Nitidulidae are added to the faunal list of New Brunswick; the latter species is new to the Maritime provinces. Two species of Cerylonidae, Philothermus glabriculus LeConte and Cerylon unicolor (Ziegler), are reported for the first time for New Brunswick. Philothermus glabriculus is new for the Maritime provinces. Two species of Endomychidae, Hadromychus chandleri Bousquet and Leschen and Danae testacea (Ziegler) are newly recorded for New Brunswick. Three species of Coccinelidae, Stethorus punctum punctum (LeConte), Naemia seriata seriata Melsheimer, and Macronaemia episcopalis (Kirby) are added to the provincial list. Macronaemia episcopalis (Kirby) is a species new to the Maritime provinces. Nine species of Latridiidae, Cartodere nodifer (Westwood), Dienerella ruficollis (Marsham), Enicmus aterrimus Motschulsky, Enicmus fictus Fall, Encimus histrio Jay and Tomlin, Lathridius minutus (Linnaeus), Stephostethus productus Rosenhauer, Corticaria elongata (Gyllenhal), and Corticarina longipennis (LeConte) are newly recorded for New Brunswick. Stephostehus productus is newly recorded from Canada. Collection and habitat data are presented for all these species.  相似文献   

13.
William Simkulet 《Bioethics》2019,33(9):1002-1011
Most serious contemporary opposition to abortion is grounded on the belief that human fetuses are members of the same moral category as beings like us, and that the loss of any such life is one of the worst possible losses. Substance view theorists oppose abortion for this reason: in their view beings like us are essentially rational substances with inherent moral worth, and those who perform induced abortion fail to recognize this moral worth. In a recent series of articles, Rob Lovering presents reductio‐style arguments against the substance view, in part arguing that it is inconsistent with our intuitions in rescue and spontaneous abortion cases. In a recent reply, Henrik Friberg‐Fernros argues that the substance view can evade these problematic implications because of a distinction between killing and letting die. According to this argument, the fetus’s right to life is a negative right not to be killed, not a positive right to be rescued, thus the anti‐abortion theorist who lets fetuses die acts acceptably. I argue this stance fails to recognize the inherent moral worth that the substance view contends fetuses possess. One who refrains from saving a person, or doesn’t care how many people she saves, cannot reasonably claim to value life. Furthermore, this stance is at odds with most contemporary anti‐abortion views that oppose induced abortions of both the killing and letting die variety.  相似文献   

14.
A review is presented of issues relevant to the definition, measurement, and classification of stimuli, situations, and environments. Problems such as the lack of adequate definitions of concepts, error and bias in measurement procedures, confusion between measurement of a concept and measurement of its behavioral effects, and the lack of agreement among alternative measures are emphasized. It is suggested that concepts be defined in terms of objective characteristics while allowing for the study of the transactional relationship between organism and environment. The work of the ethologists in defining stimuli while studying their relationship to different organismic states and situational contexts is emphasized in this regard. Following Brunswik, it is also suggested that wherever possible there be a representative sampling of variables in natural settings. Note from the editors: From time to time, Human Ecology will publish a review article. Our first in this series is a review by a psychologist of basic definitional and conceptual problems in environmental studies.This paper was prepared while the author was a Visiting Research Fellow at the Educational Testing Service. The support of ETS and my colleagues in the Division of Psychological Studies is gratefully acknowledged. The review was also supported in part by a grant from the Rutgers University Research Council.  相似文献   

15.
Oral cancer is one of the main causes of cancer-related deaths in South-Asian countries. There are very limited treatment options available for oral cancer. Research endeavors focused on discovery and development of novel therapies for oral cancer, is necessary to control the ever rising oral cancer related mortalities. We mined the large pool of compounds from the publicly available compound databases, to identify potential therapeutic compounds for oral cancer. Over 84 million compounds were screened for the possible anti-cancer activity by custom build SVM classifier. The molecular targets of the predicted anti-cancer compounds were mined from reliable sources like experimental bioassays studies associated with the compound, and from protein-compound interaction databases. Therapeutic compounds from DrugBank, and a list of natural anti-cancer compounds derived from literature mining of published studies, were used for building partial least squares regression model. The regression model thus built, was used for the estimation of oral cancer specific weights based on the molecular targets. These weights were used to compute scores for screening the predicted anti-cancer compounds for their potential to treat oral cancer. The list of potential compounds was annotated with corresponding physicochemical properties, cancer specific bioactivity evidences, and literature evidences. In all, 288 compounds with the potential to treat oral cancer were identified in the current study. The majority of the compounds in this list are natural products, which are well-tolerated and have minimal side-effects compared to the synthetic counterparts. Some of the potential therapeutic compounds identified in the current study are resveratrol, nimbolide, lovastatin, bortezomib, vorinostat, berberine, pterostilbene, deguelin, andrographolide, and colchicine.  相似文献   

16.
Piotrowska A  Bajguz A 《Phytochemistry》2011,72(17):2097-2112
Phytohormones, including auxins, abscisic acid, brassinosteroids, cytokinins, ethylene, gibberellins, and jasmonates, are involved in all aspects of plant growth, and developmental processes as well as environmental responses. However, our understanding of hormonal homeostasis is far from complete. Phytohormone conjugation is considered as a part of the mechanism to control cellular levels of these compounds. Active phytohormones are changed into multiple forms by acylation, esterification or glycosylation, for example. It seems that conjugated compounds could serve as pool of inactive phytohormones that can be converted to active forms by de-conjugation reactions. Some conjugates are thought to be temporary storage forms, from which free active hormones can be released after hydrolysis. It is also believed that conjugation serves functions, such as irreversible inactivation, transport, compartmentalization, and protection against degradation. The nature of abscisic acid, brassinosteroid, ethylene, gibberellin, and jasmonate conjugates is discussed.  相似文献   

17.
It is still not possible to provide an evidence-based answer to the question of whether regular exercise is essential for normal growth. It is also unclear whether very low levels of exercise result in growth deficits. Regular exposure to exercise is characterized by heterogeneity in responsiveness, with most individuals experiencing improvements in fitness traits but a significant proportion showing only very minor gains. Whether a sedentary mode of life during the growing years results in a permanent deficit in cardiorespiratory fitness or a diminished ability to respond favorably to regular exercise later in life remains to be investigated. Although several genes have been associated with fitness levels or response to regular exercise, the quality of the evidence is weak mainly because studies are statistically underpowered. The special case of the obese, sedentary child is discussed, and the importance of the "energy gap" in the excess weight gain during growth is highlighted. Obese, sedentary children have high blood pressure, dyslipidemia, elevated glycemia and type 2 diabetes, hepatic steatosis, respiratory problems, orthopedic complications, and other health disorders more frequently than normal weight, physically active children. The role of genetic differences in the inclination to be sedentary or physically active is reviewed. An understanding of the true role of genetic differences and regular exercise on the growth of children will require more elaborate paradigms incorporating not only DNA sequence variants and exercise exposure but also information on nutrition, programming, and epigenetic events during fetal life and early postnatal years.  相似文献   

18.
It is frequently claimed that green algae are intrinsically more productive, often by orders of magnitude, than higher plants commonly grown as crops for food. There is no firm evidence for this belief. On the contrary, there is much experience which shows that algae are not more but less productive. Under optimal conditions, all green organisms photosynthesize at the same rate in low light and, whilst commonly cultivated ‘sun’ species show some differences in rate in full light, these do not translate into widely different rates of accumulation of biomass. Accordingly, irrespective of crop, one acre of land, pond or bioreactor, can annually yield about enough biomass to fuel one motor vehicle or meet the calorific requirement of several people. This amount of biomass is not sufficient to make other than a very small contribution to our present road transport requirements and yet contributes significantly to global food shortages and rising prices. Reliable evidence also suggests that, if all of the inputs are taken into account, the net energy gain of liquid biofuels, derived either from algae or terrestrial crops, is either very modest or non-existent and will therefore bring about little or no sparing of carbon dioxide emissions.  相似文献   

19.
We report 19 new species records for the faunal list of Coleoptera in New Brunswick, Canada, six of which are new records for the Maritime provinces, and one of which is new Canadian record. We also provide the first recent records for five additional species in New Brunswick. One new species of Stenotrachelidae, Cephaloon ungulare LeConte, is added to the New Brunswick faunal list. Additional records are provided for Cephaloon lepturides Newman, as well the first recent record of Nematoplus collaris LeConte. Two species of Oedemeridae, Asclera puncticollis (Say) and Asclera ruficollis (Say), are newly reported for New Brunswick, and additional locality and bionomic data are provided for Calopus angustus LeConte and Ditylus caeruleus (Randall). The records of Ditylus caerulus are the first recent records for the province. Three species of Meloidae, Epicauta pestifera Werner, Lytta sayi LeConte, and Meloe augustcollis Say are reported the first time for New Brunswick; Epicauta pestifera is newly recorded in Canada. Lacconotus punctatus LeConte and the family Mycteridaeis newly recorded for New Brunswick. The first recent records of Borus unicolor Say (Boridae) are reported from the province. One new species of Pythidae, Pytho siedlitzi Blair, and the first recent records of Pytho niger Kirby are added to the faunal list of New Brunswick. Three species of Pyrochroidae are newly reported for the province, including Pedilus canaliculatus (LeConte) and Pedilus elegans (Hentz), which are new for the Maritime provinces. Five species of Anthicidae and the first recent record of Anthicus cervinus LaFerté-Sénectére are newly reported for New Brunswick. Anthicus melancholicus LaFerté-Sénectère, Sapintus pubescens (LaFerté-Sénectère), Notoxus bifasciatus (LeConte), and Stereopalpus rufipes Casey are new to the Maritime provinces faunal list. Ambyderus granularis (LeConte) is removed from the faunal list of the province. Three species of Aderidae, Vanonus huronicus Casey, Zonantes fasciatus (Melsheimer), and Zonantes pallidusWerner, are newly recorded for New Brunswick; Zonantes fasciatus and Vanonus huronicus are new for the Maritime provinces' faunal list. Collection data, bionomic data, and distribution maps are presented for all these species.  相似文献   

20.
Nodes in networks are often of different types, and in this sense networks are differentiated. Here we examine the relationship between network differentiation and network size in networks under economic or natural selective pressure, such as electronic circuits (networks of electronic components), Legos (networks of Lego pieces), businesses (networks of employees), universities (networks of faculty), organisms (networks of cells), ant colonies (networks of ants), and nervous systems (networks of neurons). For each of these we find that (i) differentiation increases with network size, and (ii) the relationship is consistent with a power law. These results are explained by a hypothesis that, because nodes are costly to build and maintain in such "selected networks", network size is optimized, and from this the power-law relationship may be derived. The scaling exponent depends on the particular kind of network, and is determined by the degree to which nodes are used in a combinatorial fashion to carry out network-level functions. We find that networks under natural selection (organisms, ant colonies, and nervous systems) have much higher combinatorial abilities than the networks for which human ingenuity is involved (electronic circuits, Legos, businesses, and universities). A distinct but related optimization hypothesis may be used to explain scaling of differentiation in competitive networks (networks where the nodes themselves, rather than the entire network, are under selective pressure) such as ecosystems (networks of organisms).  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号