教学课程资源库 更多>>

关键词： 设计性实验   实验方案   实验设计  

摘要： 设计性实验的完成是学生较高层次综合能力的体现。科学、合理、周密、巧妙的实验设计,可以使学生学会实验设计的方法,能使学生从理论知识的应用到基本实验技能以及分析与解决问题的能力得到全面的训练。本文主要阐述了利用开放实验室,在植物生理学实验中,制订实验方案,设计实验过程,实施设计性实验的前提以及设计性实验如何进行考核评定。

关键词： Scientific Methodology   Evaluation Criteria   Botany   Evolution   Inquiry   Science Instruction   Science Experiments  

摘要： The article describes an experiment to help students explore how a single species can adapt to a variety of climates and, potentially, become a new species. The project involves the use of ecotypes of Arabidopsis thaliana and integrates biology, geography, earth sciences, and mathematics. Students will grow different ecotypes of Arabidopsis under different environmental conditions and measure fitness of the ecotype to each treatment. A list of materials is provided, along with preparation and discussion topics.

关键词： conventional and time-resolved Lane X-ray crystallography   domain movements   mechanism-based inhibitors   substrate analogues   transition-state mimics  

摘要： Higher plant, family GH3 beta-D-glucan glucohydrolases exhibit exo-hydrolytic and retaining (e -> e) mechanisms of action and catalyze the removal of single glucosyl residues from the non-reducing termini Of beta-D-linked glucosidic substrates, with retention of anomeric configuration. The broad specificity beta-D-glucan glucohydrolases are likely to play roles in cell wall re-modelling, turnover of cell wall components and possibly in plant defence reactions against pathogens. Crystal structures of the barley beta-D-glucan glucohydrolase, obtained from both native enzyme and from the enzyme in complex with a substrate analogues and mechanism-based inhibitors, have enabled the basis of substrate specificity, the mechanism of catalysis, and the role of domain movements during the catalytic cycle to be defined in precise molecular terms. The active site of the enzyme forms a shallow 'pocket' that is located at the interface of two domains of the enzyme and accommodates two glucosyl residues. The propensity of the enzyme to hydrolyze a broad range of substrates with (1 -> 2)-, (1 -> 3)-, (1 -> 4)- and (1 -> 6)-beta-D-glucosidic linkages is explained from crystal structures of the enzyme in complex with non-hydrolysable S-glycoside substrate analogues, and from molecular modelling. During binding of gluco-oligosaccharides, the glucosyl residue at subsite -1 is locked in a highly constrained position, but the glucosyl residue at the +1 subsite is free to adjust its position between two tryptophan residues positioned at the entry of the active site pocket. The flexibility at subsite +1 and the projection of the remainder of the substrate away from the pocket provide a structural rationale for the capacity of the enzyme to accommodate and hydrolyze glucosides with different linkage positions and hence different overall conformations. While mechanism-based inhibitors with micromolar K-i constants bind in the active site of the enzyme and form esters with the catalytic nucle

关键词： 花药开裂   细胞学   分子生物学   机制  

摘要： 植物花药开裂具有重要的生物学意义,花药开裂异常所导致的最直接后果为花粉粒不能正常散粉,影响到植物受精过程。现从细胞和分子生物学角度综述了植物花药开裂过程中花药组织的细胞结构和生理变化及调控花药开裂相关基因的分离和克隆。

关键词： 古林箐秋海棠   资源状况   保护措施   生物学特性  

摘要： 对云南特有植物古林箐秋海棠(Begonia *** et ***)的资源状况进行了全面调查研究。结果表明,古林箐秋海棠仅在模式产地存在两个居群,目前已处于濒危状态。开垦等人为破坏活动导致生境破碎化是其濒危的主要原因,为此提出了保护对策,并对古林箐秋海棠的生物学特性进行了研究。

关键词： allergens   evolution   protein superfamilies   prolamins   cupins   profilins   Bet v 1  

摘要： The majority of plant food allergens can be grouped into just 4 protein families. This review summarizes the evolutionary relationships of allergenic and nonallergenic members of these families. Proteins from the prolamin superfamily have been described in vascular plants. This superfamily contains several allergenic (2S albumins, nonspecific lipid transfer proteins, and cereal amylase and protease inhibitors) and nonallergenic (hybrid proline-rich proteins, cereal indolines, and alpha-globulins) member families. The cupin superfamily comprises numerous functionally highly diverse protein families from all groups of organisms. However, allergenicity within the cupins is confined to the vicilin and legumin seed storage proteins. Profilins are ubiquitous eukaryotic proteins that are nonallergenic, with the exception of profilins from flowering plants. Finally, the Bet v 1 superfamily contains the pathogenesis-related proteins 10 family, the family of major latex proteins and ripening-related proteins, the norcoclaurine synthases, and the cytokinin-binding proteins, with pathogenesis-related proteins 10 family members from certain taxa being the only allergenic members. The study of the distribution of allergenic and nonallergenic members of protein families will provide new insights into the evolution of allergenicity and the factors that make proteins allergenic.

关键词： CRUCIFERAE   BOTANY   FLOWERS   POLLINATION   INFLORESCENCES  

摘要： Physaria ludoviciana (Brassicaceae) is rare in Illinois, Minnesota, and Wisconsin. Environmental effects on floral development are unclear. Both self-compatibility and self-incompatibility occur within Physaria species. Objectives were to describe flowers, to determine how photoperiod affects flower development, and to predict whether flowers are self-compatible or self-incompatible. For photoperiods, greenhouse-grown plants were placed in either 16 or 8 hr photoperiods. Inflorescences and open flowers were counted weekly. For pollination, flowers were self-pollinated or cross-pollinated. Plants developed inflorescences after 20 and 28 d in long and short days, respectively. Inflorescences/plant increased for both photoperiods throughout the study. In short days, plants produced more inflorescences (10.8/plant) than in long days (7.1/plant). Anthesis started at 48 and 56 d for long and short days, respectively. Blooming peaked at 83 d (4.9 flowers/plant/day) for long days, and at 98 d (3.5 flowers/plant/day)

关键词： Austromusotima camptozonale   mating biology   Lygodium microphyllum  

摘要： Austromusotima camptozonale (Hampson) is under investigation as a potential biological control agent of Old World climbing fern, Lygodium microphyllum (Cav.) R. Br., which is a serious invasive weed in southern Florida. Studies were conducted to investigate aspects of the mating biology of A. camptozonale with a view to improving field colonization efforts. A laboratory colony of A. camptozonale had a female-biased sex ratio of 1:1.3 male:female, with females emerging slightly earlier than males. The majority of female moths mated only once, even when they were confined with multiple males for several nights. Sex ratio had a significant effect on the percentage of females that were mated, with higher percentages of females mated at high male sex ratios. However sex ratio had no effect on the number of times individual females mated. Larval production was significantly higher in colony cages with high male sex ratios, and this was likely due to the higher percentages of females that were mated in these cages. Data suggest that A. camptozonale females are likely to be functionally monandrous under field conditions. Females produced a lifetime average of 61.2 +/- 9.7 larvae, and were short-lived, surviving an average of 5.7 +/- 0.5 d. Females began oviposition on the first night after mating and continued until the day of their death. However 90% of eggs were deposited between the first and third night after mating. Due to the short lifespan of female moths, adults may not be the best life stage for field release in a biological control program, owing to likely disruption of critical mating and oviposition activities. Elevating the ratio of males in colony mating cages is a strategy for maximizing female reproductive output.

关键词： BIOLOGICAL research   PLANTS   AGRICULTURAL industries   CROP yields   BIOMASS energy  

摘要： Over the next 50 years, considerable stress will be placed on worldwide crop production by a combination of factors, including an increased human population, an increase in the crops used per person, and a number of environmental issues. Given currenttrends, it will be necessary to approximately double yields worldwide during this time period, and meeting this challenge will require a considerable effort. This article explores the nature of the challenge and the requirements for meeting it. These include novel technical advances and fundamental discoveries as well as new multidisciplinary ways of organizing research to ensure that researchers and technologists target the advances and discoveries that are most needed and effectively use them to enhance important crop traits.

关键词： auxin biosynthesis   auxinic herbicide   auxin homeostasis   auxin receptor   herbicide detection   herbicide resistance   phytohormone   phytotoxicity   plant growth regulator   signal transduction   TIRI   AFB   ABP1  

摘要： Auxinic herbicides mimic the effects of natural auxin. However, in spite of decades of research, the site(s) of action of auxinic herbicides has remained unknown and many physiological aspects of their function are unclear. Recent advances in auxin biology provide new opportunities for research into the mode of action of auxinic herbicides. Of considerable interest is the discovery of auxin receptors (TIR1 and possibly ABP1) that may lead to the discovery of auxinic herbicide site(s) of action. Knowledge of auxin-conjugating enzymes and auxin signal transduction components may shed new light on herbicide activity, selectivity in dicots, and mechanisms leading to phytotoxicity in sensitive plants. Analysis of genes induced in response to auxin may provide a novel approach for detection of off-target herbicide injury in crops. For example, the auxin-responsive gene GH3 is highly and specifically induced in response to auxinic herbicides in soybean, and may offer a novel method for diagnosing auxinic herbicide injury. Advances in our understanding of auxin biology will provide many new avenues and opportunities for auxinic herbicide research in the future. (C) 2007 Elsevier Inc. All rights reserved.