中国西南与台湾地区维管植物的间断分布格局及形成机制

植物的间断分布格局及其形成机制是植物地理学研究的重要问题之一。本文在对中国大陆与台湾名录整理比较的基础上,对中国西南与台湾地区的植物间断分布格局及形成机制进行了分析。结果表明,两地同种型间断分布的维管植物有198种(包括变种和亚种),隶属于56科129属,其中蕨类植物86种,裸子植物3种,双子叶植物56种,单子叶植物53种;两地异种型间断分布的维管植物有22属,隶属于15科,其中蕨类植物6属,裸子植物1属,双子叶植物7属,单子叶植物兰科8属。间断分布类群以草本植物为主,主要是蕨类和兰科植物。间断分布类群在台湾地区主要分布在中部到东北部,在大陆的分布主要集中在川东–鄂西地区、川西–滇西北地区–藏东南地区和滇东南–桂西–黔西南地区。在垂直高度上,海拔1,550–2,350m是间断分布类群最集中分布的海拔范围。我们推测中国西南与台湾地区的间断分布类群有3种来源:北半球温带、中国西南和热带亚洲来源。     

中国豆科植物一新记录种——小花红豆草

报道了小花红豆草Onobrychis micrantha Schrenk在中国新疆的分布。该种的分布区以往仅在中亚的哈萨克斯坦、巴基斯坦等地以及阿富汗和伊朗有记载。它与美丽红豆草O. pulchella Schrenk接近, 区别在于前者荚果的刺分离, 而后者荚果的刺彼此结合成膜质透明的隔膜。至此, 中国红豆草属Onobrychis的种类已达4种, 包括3个野生种和1个引进栽培种。给出了4种植物的检索表。     

Efficiency for Gene Silencing Induction in Nicotiana Species by a Viral Satellite DNA Vector

Virus-induced gene silencing （VIGS） is a useful technique for rapid plant gene function analysis. We recently reported a new VIGS vector modified from Tomato yellow leaf curl China virus （TYLCCNV） DNAβ （DNAm β）. In this study we compared in detail DNAmβ-induced gene silencing in four Nicotiana species including N. benthamiana, N. glutinosa, N. tabacum and N. paniculata. We found that DNAmβ-induced gene silencing in the four species was distinct in developing dynamics, tissue specificity, efficiency, and constancy in the plant life span. It was most efficient in N. benthamiana, where development of VIGS was most rapid, without tissue specificity and nearly 100% efficient. DNAmβ-induced gene silencing in N. glutinosa was also efficient despite being slightly less than in N. benthamiana. It initially occurred in veins, later was scattered to mesophyll, finally led to complete silencing in whole leaves. In both species, VIGS constantly expressed until the plants died. However, DNAmβ-mediated VIGS in the other two Nicotiana species, N. tabacum and N. paniculata, was significantly less efficient. It was strictly limited within the veins of the silenced leaves, and constantly occurred only over 3-4 weeks. The upper leaves that emerged later stopped showing the silencing phenotype. DNAmβ-induced gene silencing in N. benthamiana and N. glutinosa was not significantly influenced by the growth stage when the plants were agro-inoculated, and was not sensitive to high growth temperature up to 32℃. Our results indicate that this system has great potential as a versatile VIGS system for routine functional analysis of genes in some Nicotiana species.     

A NEW SPECIES OF THE GENUS EUSTOCHUS HALIDAY (HYMENOPTERA: CHALCIDOIDEA: MYMARIDAE) IN CHINA

Abstract The genus Eustochus Haliday (Hymenoptera: Chalcidoidea: Mymaridae) is briefly reviewed. A new species, Eustochus triclavatus is described and illustrated. This is the first record of the genus for China. All specimens examined are deposited in the Biological Control Research Institute, Fujian Agriculture and Forestry University, Fuzhou, China.     

A new genus from the continental slope off Brazil and the discovery of the first males in the Hirsutiidae (Crustacea: Peracarida: Bochusacea)

Montucaris distincta gen. nov. sp. nov. , a new genus and species of hirsutiid, is described from the bathyal floor of the northern South Atlantic, off Brazil. It is easily distinguished from other members of the family by the reduced, one-segmented exopods of pereopods 5 and 6 and the array of stout triangular spines present on the anterior margin of the basis and proximal endopodal segments of the third pereopod. This discovery is notable as it includes the first record of males in the family, demonstrating that hirsutiids are gonochoristic. Developmental stages including mancas, preparatory females and juvenile males were recovered, in addition to numerous brooding females and two morphs of adult males. We infer that the new genus has a life cycle involving non-feeding terminal males with regressed mouthparts. These males display a bizarre cephalic configuration, with a clearly defined transverse dorsal suture on the dorsal cephalothoracic shield just behind the articulation of mandibles, a feature present also in syncarida and in some Thermosbaenacea and that we interpret as secondary. The peracaridan affinities of the Hirsutiidae are firmly established here after settling definitively the oostegitic nature of the setose plates present on the posteromedial margin of the pereopodal coxae of brooding females. The separate ordinal rank for hirsutiids – as the Bochusacea – with respect to the Mictacea, within which they had been previously classified, is favoured here. In addition, we highlight similarities between hirustiids and tanaidaceans that warrant further investigation. © 2006 The Linnean Society of London, Zoological Journal of the Linnean Society , 2006, 148 , 169–208.     

A south-to-north biogeographic hypothesis for Andean speciation: evidence from the lizard genus Proctoporus (Reptilia, Gymnophthalmidae)

Aim The lizard genus Proctoporus Tschudi, 1845 was used as a model to test the South‐to‐North Speciation Hypothesis (SNSH) for species groups occurring in the Andes Mountains of South America. This hypothesis proposes that speciation of high Andean taxa followed a south‐to‐north pattern, generally coinciding with the progression of final uplift of the Andes. According to SNSH, a phylogenetic hypothesis of relationships of a taxonomic group occurring in the high Andes would show a branching pattern in which the southernmost species diverged first, followed by the more northern species, and so on in a northerly pattern. Location The central and northern Andes Mountains in South America. Methods A phylogenetic hypothesis was reconstructed for all species of the lizard genus Proctoporus by examining the external morphology of 341 individuals. This phylogeny was then examined to determine monophyly of the genus, distribution patterns of species groups, and congruence with SNSH. Results The genus Proctoporus did appear to be monophyletic and, therefore, it was valid to use this group to assess SNSH. The southernmost species were found to be the most basal, which was consistent with SNSH. The species occurring in the northern Andes did not exactly match the SNSH prediction. The Venezuelan and Trinidadian species did appear to be highly derived, as predicted by the hypothesis, but the Ecuadorian and Colombian species did not form a particular pattern in relation to the hypothesis. Main conclusions The SNSH does appear to have predictive power with regard to large‐scale distribution patterns. The finer‐scale patterns of speciation in the Andes, however, appear to be a more complex phenomenon that cannot be fully explained by a simple hypothesis. It is important to have a testable hypothesis in hand with which to compare data from disparate species groups. The incorporation of phylogenetic data of other high Andean taxa with similar distribution patterns is necessary to determine the full utility of SNSH in explaining evolutionary patterns in the Andes of South America.     

'First' appearances in the Cenozoic land-mammal record of the Greater Antilles: significance and comparison with South American and Antarctic records

Aim Through analysis of fossil records, the aim of this paper is to show that fossil representatives of at least three land‐mammal clades (pitheciine atelid primates, heteropsomyine echimyid rodents, and megalonychid phyllophagan xenarthrans) that once lived in the Greater Antilles are as old as, if not older than, ‘first’ occurrences of these same groups on the South American mainland. Location Greater Antilles, South America, Antarctic Peninsula. Methods Analysis of Cenozoic land‐mammal fossil records for the three areas. Results Comparison reveals an interesting similarity to the Tertiary vertebrate palaeontological record for the Antarctic Peninsula (Seymour Island), in the sense that the latter also includes early (Eocene) representatives of some typical ‘South American’ groups (e.g. meridiungulates, sloths, certain marsupial groups). Conclusions Given how limited the Antillean and Antarctic records are in quantity and quality, it seems unlikely that these ‘first’ appearances have much bearing on real origins (basal divergences). Rather, it suggests that the fossil basis for interpreting the origin and earliest diversification of ‘South American’ clades during the latest Cretaceous/early Cenozoic is probably even scantier than generally realized. In particular, the Antillean record strengthens arguments that some crown‐group continental lineages are considerably older than fossil evidence currently allows – a point increasingly (if unevenly) supported by molecular studies of many of the same clades.     

Flood-deposited wood debris and its contribution to heterogeneity and regeneration in a semi-arid riparian landscape

We investigated whether large woody debris (LWD) piles create nodes of environmental resources that contribute to the recovery of riparian vegetation and that also augment the heterogeneity and resilience of the riverine system. River and riparian systems are typified by a large degree of heterogeneity and complex interactions between abiotic and biotic elements. Disturbance such as floods re-distribute the resources, such as LWD, and thereby add greater complexity to the system. We examined this issue on a semi-arid savanna river where a ~100-year return interval flood in 2000 uprooted vegetation and deposited substantial LWD. We investigated the micro-environment within the newly established LWD piles and compared this with conditions at adjacent reference sites containing no LWD. We found soil nutrient concentrations to be significantly higher in LWD piles compared with the reference plots (total N +19%, available P +51%, and total C +36%). Environmental variables within LWD piles and reference sites varied with landscape position in the river–riparian landscape and with LWD pile characteristics. Observed differences were generally between piles located in the terrestrial and riparian areas as compared to piles located on the macro-channel floor. After 3 years the number and cover of woody species were significantly higher when associated with LWD piles, regardless of landscape position or pile type. We conclude that LWD piles formed after large floods act as resource nodes by accumulating fine sediments and by retaining soil nutrients and soil moisture. The subsequent influence of LWD deposition on riparian heterogeneity is discerned at several spatial scales including within and between LWD piles, across landscape positions and between channel types. LWD piles substantially influence the initial developmental of riparian vegetation as the system regenerates following large destructive floods.     

Engyprosopon vanuatuensis, a new species of bothid flounder (Pleuronectiformes: Bothidae) from off Vanuatu, South West Pacific

A new bothid flounder, Engyprosopon vanuatuensis, is described on the basis of 15 specimens (9 males and 6 females, 41.1–55.8mm in standard length) collected from deep waters (163–165m) off Vanuatu Island in 1994 during the French exploratory cruise MUSORSTOM 8. The new species clearly differs from its congeners in having a short body, big eyes, large scales, and many gill rakers without serrations. Remarkable sexual dimorphism appears in interorbital width, anterior curve of head profile, rostral and orbital spines, length of ocular-side pectoral fin, small dots on eyes, and pigmentation of blind-side body.