教学课程资源库 更多>>

关键词： Psigida walkeri   host specificity   Citheroniidae   Mimosa diplotricha   Mimosa invisa   Mimosa rixosa   Mimosa velloziana   weed biological control  

摘要： Studies on the biology and host specificity of the citheroniid moth Psigida walkeri, native to Brazil and Colombia, were undertaken in Brazil and Australia. These studies were a component of a biological control project in Australia and the South Pacific for the invasive tropical weed Mimosa diplotricha. Biological studies focused on aspects of adult behavior, longevity, oviposition, and lifestage development. Host-specificity testing was undertaken on 110 plant species from 29 families, incorporating the family Mimosaceae and close relatives, and families containing economically important species. Twenty-nine of these plant species supported some degree of larval feeding. Psigida walkeri readily fed and developed for two or more generations on the known host plants M. diplotricha (=M. invisa), M. rixosa, M. velloziana, M. somnians, and on other test plant species M. pigra, Neptunia dimorpantha, and N. major. Therefore, these three additional species are considered potential hosts. Mimosa pudica, M. scabrella, and Acacia nilotica supported development of second generation larvae, but larvae were small, unthrifty, and eventually died. In choice tests, P. walkeri developed through to pupae and leaf consumption ranging from 10 to 100% on 5 bipinnate Acacia species, 5 Leucaena species, Calliandra calothyrsus, and Vigna unguiculata. These plant species could support larval development over one generation. There was no larval development beyond second instar in a series of no-choice tests;however, defoliation outbreaks could possibly occur on these 12 species from time to time. Due to the wide potential host range of this insect and especially the risk to native Australian Neptunia species, P. walkeri was not released in Australia. (C) 2001 Academic Press.

关键词： Adhesiveness   Angiosperms/cytology   Angiosperms/cytology   Angiosperms/physiology   Angiosperms/physiology   Calcium/physiology   Carbohydrates/physiology   Culture Techniques   Culture Techniques   Plant Components/cytology   Plant Components/physiology   Pollen/physiology   Reproduction   Seeds/physiology   Surface Properties  

摘要： Like mating in other organisms, attraction between the opposite sexes inplants is important for reproduction. Chance brings pollen grains (the male gametophytes) to thesurface of the pistil (the female reproductive organ), but it takes active male-female interplaywithin the pistil to achieve fertilization. Biologists have long puzzled over the guidance cuesproduced by the pistil that direct the tube growing from the pollen grain toward its target, theembryo sac where the egg resides. On page 1480 of this issue, Higashiyama et al. (1), working in theflow: ering plant Toreniafournieri, show that the paired synergid cells of the embryo sac are thesource of guidance cues that entice pollen tubes to enter the ovules of the ovary. The pistil iscomposed of a pollen receptive stigma that is connected to the ovary by a structure known as thestyle (see the figure). Each haploid pollen grain develops a pollen tube that transports two malegametes from the stigma to the ovules of the ovary. The pollen tube elongates through the femalediploid tissues of the style by extending its tip, reminiscent of the elongation of axons duringneural development in mammals (2-4). The female gametophyte (embryo sac) is composed of sevenhaploid cells including the paired synergid cells and resides in the ovule (see the figure). Uponarrival in the ovary, the pollen tube adjusts its growth trajectory to gain access to an ovulethrough an aperture called the micropyle (see the figure). Although multiple pollen tubes mayapproach a micropyle, usually only one successfully penetrates the embryo sac. As it does so, thepollen tube raptures, releasing the male gametes. In a double fertilization process, the gametesthen fuse with the egg cell and the binucleated central cell producing the embryo and the triploidendosperm, respectively, of a future seed (5).

关键词： 红景天   珍稀濒危植物   生殖生物学   无性繁殖   组织培养   抗冻蛋白   次生代谢产物  

摘要： 景天科(Crassulaceae)红景天属(Rhodiiola L.)植物主要分布在北半球的喜马拉雅山区、亚洲西北部和北美洲,共90多种,而中国就有70多种,主要产于华北、东北、西南、西北和华中等地区[1].我国对红景天的基础研究始于80年代初,已取得了可喜的成绩.

关键词： 植物生物学   创新能力   教学改革   学生   教学内容   教学方法   教学手段   考核体系  

摘要： 围绕如何在教学过程中培养学生的创新能力 ,介绍了植物生物学教学实践的四个环节 :教学内容、教学方法、教学手段和考试考核体系诸方面所作的改革尝试 。

关键词： host-parasite interactions   population genetics   liver fluke   intermediate and definitive host  

摘要： Knowledge of the population dynamics of parasites and their hosts is essential to build veterinary and health programs. The example chosen is that of Fasciola hepatica, a food-borne trematode responsible for severe human and animal infections on the five continents. In this paper, we review the relationships between the liver fluke and its intermediate (mollusc) and definitive (vertebrate) hosts. (C) 2001 Editions scientifiques et medicales Elsevier SAS.

关键词： Abscisic Acid/pharmacology   Animals   Arabidopsis/cytology   Arabidopsis/cytology   Arabidopsis/genetics   Arabidopsis/genetics   Arabidopsis/metabolism   Arabidopsis/metabolism   Arabidopsis Proteins   Cell Division   Gene Silencing   Genes, Plant   GTP-Binding Protein alpha Subunits   Guanosine Diphosphate/metabolism   Guanosine Triphosphate/metabolism   Heterotrimeric GTP-Binding Proteins/chemistry   Heterotrimeric GTP-Binding Proteins/genetics   Heterotrimeric GTP-Binding Proteins/metabolism   Hydrogen-Ion Concentration   Indoleacetic Acids/metabolism   MAP Kinase Signaling System   Models, Biological   Mutation   Plant Leaves/cytology   Plant Leaves/drug effects   Plant Leaves/physiology   Plant Leaves/ultrastructure   Plants/cytology   Plants/genetics   Plants/metabolism   Signal Transduction  

摘要： The genomics revolution provides almost daily confirmation of the relatedness of eukaryotes, especially when it comes to core activities such as cell division and signal transduction. Against this background of common heritage, it is the differences among eukaryotes that become particularly interesting. In this issue of Science, reports by Ullah (page 2066) and Wang (page 2070) highlight one of the striking differences between signaling pathways in plant and animal cells--the degree to which each kingdom relies on heterotrimeric GTP-binding proteins (G proteins) to transduce signals from plasma membrane receptors to the cell interior.

关键词： Biodegradation, Environmental   Carboxylic Ester Hydrolases/metabolism   Erwinia/physiology   Homoserine/analogs & derivatives   Homoserine/metabolism   Plant Diseases/microbiology   Plants/microbiology   Signal Transduction  

摘要： Many bacteria communicate by using dedicated signalling molecules. Signal-degrading enzymes from other bacteria interrupt the conversation, and can protect tobacco and potato plants from infection.

关键词： 高效液相色谱法   木霉素   植物激素类物质   生理活性   HPLC   生物学  

摘要： 经对峙培养、温室实验和拮抗作用机制测定等筛选出4个木霉菌候选生防菌株TV-1、TR13、T918和A405.候选生防菌株代谢产物生理活性的测定结果表明,供试菌株代谢液中含有活性的赤霉素类物质.采用高效液相色谱法(HPLC)和生物测定法对4个候选生防菌株代谢液中的植物激素类物质的种类和含量进行了进一步分析.高效液相色谱测定结果:4个木霉菌株代谢液中均存在吲哚乙酸和赤霉素GA<,3>,其中赤霉素GA<,3>的含量较高,但代谢液中总的激素含量水平并不高,木霉菌株TR13中存在少量的脱落酸.生物测定的结果为:4个供试落株代谢液中均存在少量赤霉类素物质.两项测定结果表明,木霉菌对植物生长的保进作用中,植物激素类物质起一定的作用.

关键词： 血清学方法   分子生物学方法   检测   植物病毒   研究进展  

摘要： 血清学方法是目前最常用的植物病毒检测方法 ,分子生物学方法检测植物病毒正处于从实验研究转向实际应用阶段。介绍了这 2类方法的研究进展、应用状况 ,并对几种常用方法 (ELISA、RT -PCR、IC -PCR、hybridization)

关键词： 农业教育科研   产教研结合   农业微生物学   植物病理学家   俞大绂   人物传记