野牡丹科植物与蜂类某些类群的进化关系初探

本文提出熊蜂、胡蜂等采集野牡丹科植物花粉的现象,进而探讨了野牡丹科植物与熊蜂、胡蜂……等之间的共同进化关系,并指出野牡丹科植物与熊蜂等类群,在系统进化中有平行进化的关系。     

The phenolics and a hydrolysable tannin polyphenol oxidase of Medinilla magnifica

The production of viable meristem cultures of Medinilla magnifica has proved to be very difficult. This may be due, in part, to a pronounced ‘browning’ response of the tissues on cutting. For this reason the phenolic compounds and the hydrolysable-tannin polyphenol oxidase from Medinilla were studied. The distribution of the compounds was: simple phenols 19% , flavonoids 5% , hydrolysable tannins 69% , condensed tannins 7%. Amongst the simple phenols and phenolic acids, the following were identified: phloroglucinol, p-hydroxybenzoic acid, vanillic acid, protocatechuic acid, gallic acid (both in free and bound form the most abundant simple phenol), syringic acid, trans-p-coumaric acid, trans-ferulic acid and trans-caffeic acid. No kaempferol or quercetin or their derivatives were detected but condensed tannins are present. Methods for the extraction, fractionation and quantitative determination of phloroglucinol and the phenolic acids, as well as correction factors for losses during the extraction, alkali treatment and derivatization, are presented in a supplementary publication. With regard to the hydrolysable tannin polyphenol oxidase activity of Medinilla stems, the enzyme(s) is rather specific since at neither of its two pH optima (6 and 7) could a classical polyphenol oxidase activity be detected. The enzyme was strongly inhibited by 2-mercaptoethanol. Preliminary experiments have further shown that in addition to the hydrolysable tannins of the tissue, the ferrous ions of the medium, and oxygen together with the hydrolysable tannin polyphenol oxidase could play a role in the browning response. Ways to overcome this difficulty have been suggested.     

Historical biogeography of the Southeast Asian and Malesian tribe Dissochaeteae (Melastomataceae)

The region of Tropical Southeast Asia and the Malay Archipelago is a very appealing area for research due to its outstanding biodiversity, being one of the most species-rich areas in the world with high levels of endemism, and due to its complex geological history. The high number of species in tribe Dissochaeteae (Melastomataceae) and their tendency to narrow endemism makethe tribe an ideal group for examining biogeographic patterns. We sampled 58 accessions spread over 42 accepted and two undescribed species of the Dissochaeteae. Two nuclear (ETS, ITS) and four chloroplast regions (ndhF, psbK-psbL, rbcL, rpl16) were used for divergence time estimation and ancestral area reconstruction. Results from the molecular dating analysis suggest that the diversity of Dissochaeteae in the Southeast Asian region resulted from a South American ancestor in the late Eocene. The ancestor of the Dissochaeteae might have migrated from South America to Southeast Asia via North America and then entered Eurasia over the North Atlantic land bridge during the Eocene. The origin and early diversification of the Dissochaeteae in Southeast Asia dates back to the middle Oligocene, and most of the genera originated during the Miocene. Indochina and Borneo are most likely the area of origin for the most recent common ancestor of the Dissochaeteae and for many of the early diverging clades of some genera within Southeast Asia.     

Plant glandular trichomes mediate protective mutualism in a spider–plant system

1. Although several species of Peucetia (Oxyopidae) live strictly in association with plants bearing glandular trichomes worldwide, to date little is known about whether these associations are mutualistic. 2. In this study we manipulated the presence of Peucetia flava on the glandular plant Rhynchanthera dichotoma in the rainy and post‐rain season, to test the strength of its effects on leaf, bud, and flower damage and plant reproductive output. In addition, we ran independent field experiments to examine whether these sticky structures improve spider fidelity to plants. 3. Peucetia suppressed some species of foliar phytophages, but not others. Although spiders have reduced levels of leaf herbivory, this phenomenon was temporally conditional, i.e. occurred only in the post‐rain but not in the rainy season. Floral herbivory was also reduced in the presence of spiders, but these predators did not affect plant fitness components. 4. Plants that had their glandular trichomes removed retained fewer insects than those bearing such structures. Spiders remained longer on plants with glandular trichomes than on plants in which these structures had been removed. Isotopic analyses showed that spiders that fed on live and dead labelled flies adhered to the glandular hairs in similar proportions. 5. Spiders incurred no costs to the plants, but can potentially increase individual plant fitness by reducing damage to reproductive tissues. Temporal conditionality probably occurred because plant productivity exceeded herbivore consumption, thus dampening top‐down effects. Specialisation to live on glandular plants may have favoured scavenging behaviour in Peucetia, possibly an adaptation to periods of food scarcity.     

Aluminium accumulation in leaves of 127 species in Melastomataceae,with comments on the order Myrtales

The distribution and systematic significance of aluminium accumulation is surveyed based on semi-quantitative tests of 166 species, representing all tribes and subfamilies of the Melastomataceae as well as a few members of related families within the Myrtales. The character is strongly present in nearly all members of the Memecylaceae and in most primitive taxa of the Melastomataceae, while non-accumulating taxa are widespread in the more derived tribes of the Melastomataceae. The variable distribution of Al accumulation in advanced clades of the latter family is probably associated with the tendency to herbaceousness, although it is unclear whether the more herbaceous representatives have developed more specialized Al-response mechanisms that may exclude high Al levels from the shoot. It is hypothesized that Al accumulation is symplesiomorphic for Melastomataceae and Memecylaceae, and that the feature characterizes the most primitive families in the Myrtales. Indeed, Al accumulation is also characteristic of Crypteroniaceae, Rhynchocalycaceae and Vochysiaceae. Crypteroniaceae and Rhynchocalycaceae probably take a basal position in a sister clade of the Memecylaceae and Melastomataceae, while Al accumulation suggests a basal position for Vochysiaceae in the Myrtaceae clade.     

中国特有的虎颜花属植物研究进展

通过文献考证及部分产地的野外考察,对中国特有的虎颜花属(Tigridiopalma C. Chen)植物的分类学地位和应用价值、产地与生境、濒危原因及保护建议等进行综述,以期为该属植物的保护提供参考。自1931年在广东信宜首次采到标本和1979年命名虎颜花(T. magnifica C. Chen)、成立虎颜花属以来,至今分别有90年和42年的历史,其分布区范围从最初的广东信宜、阳春等地,扩展到广东高州市,乃至广西金秀县、贵州黎平县、印江县等地,基本位于粤西或更西北;新近有学者在粤东龙门发现虎颜花属新种--无翅虎颜花(T. exalata S. J. Zeng, Y. C. Xu & D. F. Cui),其野生种群略大于粤西的虎颜花。虎颜花属植物濒危的原因包括自然和人为因素,人为干扰和破坏是主因。对其资源的保护应加强宣传教育、就地保护、迁地保护和自然回归等。     

Forest amount,not structure,influences fruit removal of two pioneer species in Atlantic forest remnants

Fruit removal is a key component of the seed dispersal process with direct consequences for plant recruitment. Anthropogenic disturbances might affect removal rates by changing frugivore diversity and their behavior. Here, we investigated the effects of local forest structure and landscape context on fruit removal of two common pioneer species of Melastomataceae family, Clidemia capitellata and Henriettea succosa in 14 Atlantic forest sites. We evaluated local forest structure, measured as canopy openness and conspecific density, and the amount of forest cover at the landscape scale measured in 2000 m buffer radius. Our results showed that the landscape context was more important than local features to explain fruit removal. The percentage of fruits removed from both species sharply decreases with forest loss and increases again in highly deforested landscapes. We demonstrate changes in fruit removal due to forest loss and suggest that both Melastomataceae species rely on the absence of other plant species, and consequently, in a less competitive environment to increase fruit removal and seed dispersal. Abstract in Portuguese is available with online material.     

Three new cecidogenous species of Palaeomystella Fletcher (Lepidoptera,Momphidae) from the Brazilian Atlantic Rain Forest

Three new cecidogenous species of Palaeomystella Fletcher (Lepidoptera, Momphidae) from the Brazilian Atlantic Rain Forest are described. Larvae of P. fernandesi Moreira & Becker, sp. n., P. rosaemariae Moreira & Becker, sp. n. and P. tavaresi Becker & Moreira, sp. n. induce galls, respectively, on Tibouchina sellowiana (Cham.) Cogn., T. asperior (Cham.) Cogn. and T. fissinervia (Schrank & Mart. ex DC.) Cogn. (Melastomataceae). Adults, immature stages and galls are illustrated, and data on life history and a preliminary analysis of mitochondrial DNA sequences, including related species, are also provided.     

Interspecific variation in the defensive responses of ant mutualists to plant volatiles

In ant–plant mutualist systems, ants patrol their host plants and search for herbivores. Such patrolling can be inefficient, however, because herbivore activity is spatio-temporally unpredictable. It has been proposed that rapid and efficient systems of communication between ants and plants, such as volatile compounds released following herbivory, both elicit defensive responses and direct workers to sites of herbivore activity. We performed bioassays in which we challenged colonies of two Amazonian plant-ants, Azteca sp. and Pheidole minutula , with extracts of leaf tissue from (1) their respective host-plant species ( Tococa bullifera and Maieta guianensis , both Melastomataceae), (2) sympatric ant-plants from the Melastomataceae, and (3) two sympatric but non-myrmecophytic Melastomataceae. We found that ants of both species responded dramatically to host-plant extracts, and that these responses are greater than those to sympatric myrmecophytes. Azteca sp. also responded to non-myrmecophytes with an intensity similar to that of sympatric ant-plants. By contrast, the response of P. minutula to any non-myrmecophytic extracts was limited. These differences may be driven in part by interspecific differences in nesting behaviour; although P. minutula only nests in host plants, Azteca sp. will establish carton satellite nests on nearby plants. We hypothesize that Azteca sp. must therefore recognize and defend a wider array of species than P. minutula .  © 2008 The Linnean Society of London, Biological Journal of the Linnean Society , 2008, 94 , 241–249.