Synthesis of 4β-acyloxypodophyllotoxin analogs modified in the C and E rings as insecticidal agents against Mythimna separata Walker

To discover the new natural-product-based insecticidal agents, four series of sixty novel 4β-acyloxypodophyllotoxin analogs modified in the C and E rings were prepared, and their insecticidal activity was tested against the pre-third-instar larvae of oriental armyworm, Mythimna separata (Walker) in vivo at the concentration of 1 mg/mL. It demonstrated that the position of the dioxo group on the E-ring of 4′-demethylepipodophyllotoxin was regioselectively controlled by the chlorine atom at its C-2′ position when 2′-chloro-4′-demethylepipodophyllotoxin was oxidized by sodium periodate. Among all the derivatives, IIIi exhibited the best potent insecticidal activity with the final mortality rate of 63.3%. To alkylacyloxy series, the proper length of the side chain at the C-4 position of Ia–g, IIa–g and IIIa–g was important for their insecticidal activity.     

华南植物园与世界一流植物园的比较研究

植物园在植物科学研究、生物多样性保护和植物资源可持续利用中具有重要作用,也是公众教育和知识传播的重要平台,具有文化传承和历史延续性的功能。以中国科学院华南植物园、英国皇家植物园邱园和美国密苏里植物园为例,从物种保护、科学研究和科学传播3 个方面对植物园进行了全面的比较和分析,为华南植物园未来发展提出了一些建议,可为华南植物园乃至我国植物园的发展提供参考依据。     

Natural-product-based insecticidal agents 14. Semisynthesis and insecticidal activity of new piperine-based hydrazone derivatives against Mythimna separata Walker in vivo

In continuation of our program aimed at the discovery and development of natural-product-based insecticidal agents, twenty-six new piperine-based hydrazone derivatives were synthesized from piperine, an alkaloid isolated from Piper nigrum Linn. The single-crystal structures of 6c, 6q and 6w were unambiguously confirmed by X-ray crystallography. Their insecticidal activity was evaluated against the pre-third-instar larvae of Mythimna separata Walker in vivo. Especially compounds 6b, 6i and 6r, the final mortality rates of which, at the concentration of 1 mg/mL, were 62.1%, 65.5% and 65.5%, respectively, exhibited more pronounced insecticidal activity compared to toosendanin at 1 mg/mL, a commercial botanical insecticide isolated from Melia azedarach. It suggested that introduction of the substituents at the C-2 position on the phenyl ring of the hydrazone derivatives was important for their insecticidal activity.     

Effects of bird seed dispersal on diversity of the invaded plants in several hedge types

The plants that invaded as weeds including woody weeds were surveyed in three hedge types, Euonymus japonicus(HEa), Viburnum awabuki (HV), and Deutzia scabra (HD), respectively, and two hedge types, Buxus microphylla var. sinica (HBa, HBb) cultivated in different habitats in Nanjing Botanical Garden Mem. Sun Yat-Sen (NBG), Nanjing of East China, from April 2001 to November 2002. Another hedge type, Euonymus japonicus (HEb) was also investigated as a contrast, cultivated in Nanjing Agricultural University (NAU), about 3 km away from NBG, between April and November 2003. In total, 1230 plant indi-viduals were found to have invaded these six hedge types, and were identified as belonging to 70 species in 57 genera and 42 fami-lies. Among these plants, 1047 individuals of 55 species were adapted for bird seed dispersal, and 161 individuals of 10 species were adapted for wind seed dispersal, but the seed dispersal mode of the other 22 individuals of five species was uncertain. Among the six hedge types, we found a significantly higher occurrence of bird-dispersed plant species than that of wind-dispersed species ( t = 5.086, df = 10, P < 0.0001) or that of species with the unknown dispersal mode ( t = 8.446, df = 10, P < 0.0001). However, the difference of occurrence between wind-dispersed species and species with the unknown dispersal mode was not significant ( t = 1.977, df = 10, P = 0.076). The number of bird-dispersed plant species recorded in the five hedge types of NBG varied from 15 to 36, M ± SD = 25.6 ± 8.1, and the Shannon-Wiener indices were between 2.151 and 2.917, M ± SD = 2.671 ± 0.306. In contrast with NBG, only 12 species of bird-dispersed plants occurred in the hedge of NAU, with a lower Shannon-Wiener index of 1.679. As a result of cluster analysis, based on Bray-Curtis similarity indices of the invaded plant species adapted for bird seed dispersal, the similarity of species composition of bird-dispersed plants between hedges was influenced to a large extent by the surrounding habitat characteristics, e.g., locality, seed source diversity, distances from seed sources, seed dispersing birds, and frequency of human disturbance, rather than simply being dependent on the hedge tree species themselves. This research suggests that hedges could attract birds to utilize their interior shelter as habitats, and therefore, would have enhanced the deposition of bird-dispersed seeds, as well as have favored seed-ling survival under hedges. Consequently, avian seed dispersal has enriched the species composition of each of the six hedge types consisting of just a single tree species. Although survival and colonization of the migrated plants will inevitably cause some influ-ences on the aesthetic view of hedges, these invaded weeds or woody weeds could be managed and suppressed through regular arti-ficial pruning and by eradication. The results indicate the ecological significance of seed sources, bird seed dispersal, and shrub patches in promoting the successional development of woody vegetation.     

Determination of the botanical origin of starch using direct potentiometry and PCA

A new approach for the determination of the botanical origin of starch is presented based on the formation of starch-triiodide complexes. The starch samples were extracted from wheat (Srpanjka), potato, maize, rye (Barun), barley (Conduct), rice, tapioca and a commercial modified starch. The amylose/amylopectin ratios of starches, among various other properties, differ between starches of different botanical origins. Triiodide ions bind characteristically to the amylose and amylopectin of the starch depending on the starch's origin. The new technique includes direct potentiometric measurements of the response of free triiodide ions in starch-triiodide solutions where the data is analysed by principal component analysis (PCA). PCA gave graphical results for statistical differentiation between starches of different botanical origins.     

基于WebGIS的植物园植物物种管理信息系统

鉴于植物园现代化管理和国内外植物资源信息交流的迫切需要,利用WebGIS系统集成技术在Internet上建立了中国科学院武汉植物园植物物种管理信息系统。系统实现了基于网络的图形属性数据的双向查询,并具有新增、编辑、缩放、漫游、定位等功能,为植物迁地保育的动态管理提供了管理工具,为科研、科普等应用部门和科技人员提供了获取植物物种信息的工作平台。文中详细介绍了该系统的设计要求、数据来源、开发运行环境、数据库构成、系统功能等。     

论动态经济植物学

经济植物学是植物科学中与生产实际及人民经济生活联系最密切的分支学科。由于过去对经济植物的市场动态重视不够 ,未能发挥植物资源的最大作用。该文提出的动态经济植物学是研究那些直接及间接对人类有利及有害的植物 ;研究它们的植物学特性 (分类、生理、生化、解剖、细胞、遗传、生态及用途等 )、栽培、繁殖、收获和加工 ,特别是市场情况、经济效益及社会效益。还对动态经济植物学的定义、研究对象、内容及教学和研究工作进行了较全面探讨 ,旨在使植物资源的开发利用更有效地为国民经济的发展服务     

Larvicidal and antifeedant activity of some plant-derived compounds to Lymantria dispar L. (Lepidoptera: Limantriidae)

Ethanol solutions of essential oil of Ocimum basilicum and its main component, linalool (both isomer forms), all in three concentrations, as well as botanical standard Bioneem (0.5%), were tested for their toxicity and antifeedant activity against the second instar gypsy moth larvae in the laboratory bioassay. The essential oil of O. basilicum was subjected to gas chromatography analysis, and totally 37 compounds were detected, of which linalool was predominantly present. All tested solutions showed low to moderate larvicidal effect in both residual toxicity test and in chronic larval mortality bioassay. Chronic mortality tests showed that obtained mortality was a consequence of starving rather than ingestion of treated leaves. However, antifeedant index achieved by application of tested solutions in feeding choice assay was remarkable. Foliar application of all tested compounds deterred feeding by L2 in the same percent as Bioneem. Antifeedant index was relatively high at all tested treatments (85-94%); moreover, the larval desensitization to repelling volatiles has not occurred after five days of observation. Low toxic and high antifeedant properties make these plant-derived compounds suitable for incorporation in integrated pest management programs, especially in urban environments.     

Population dynamics of botanical epidemics involving primary and secondary infection

In this paper we study the dynamical properties of models for botanical epidemics, especially for soil-borne fungal infection. The models develop several new concepts, involving dual sources of infection, host and inoculum dynamics. Epidemics are modelled with respect to the infection status of whole plants and plant organs (the G model) or to lesion density and size (the SW model). The infection can originate in two sources, either from the initial inoculum (primary infection) or by a direct transmission between plant tissue (secondary infection). The first term corresponds to the transmission through the free-living stages of macroparasites or an external source of infection in certain medical models, whereas the second term is equivalent to direct transmission between the hosts in microparasitic infections. The models allow for dynamics of host growth and inoculum decay. We show that the two models for root and lesion dynamics can be derived as special cases of a single generic model. Analytical and numerical methods are used to analyse the behaviour of the models for static, unlimited (exponential) and asymptotically limited host growth with and without secondary infection, and with and without decay of initial inoculum. The models are shown to exhibit a range of epidemic behaviour within single seasons that extends from simple monotonic increase with saturation of the host population, through temporary plateaux as the system switches from primary to secondary infection, to effective elimination of the pathogen by the host outgrowing the fungal infection. For certain conditions, the equilibrium values are shown to depend on initial conditions. These results have important consequences for the control of plant disease. They can be applied beyond soil-borne plant pathogens to mycorrhizal fungi and aerial pathogens while the principles of primary and secondary infection with host and inoculum dynamics may be used to link classical models for both microparasitic and macroparasitic infections.     

广西近代植物调查采集研究简志

<正> 广西位于我国南方,南面濒临北部湾,北面和湖南、贵州相邻,西部和云南高原相接,既受到太平洋气候的影响,也受到大陆气候的影响。广西的地形地质奇异,有世界著名的岩溶地形,因此植物种类极为丰富。从事植物调查采集研究的广西植物研究所成立已届五十周年,回顾过去在广西进行植物调查研究的历史,对于今后植物科学研究和工作的开展可能都有意义。