三峡库区资源植物的现状与保护

据调查统计,三峡库区有资源植物2070种,其中药用植物1006种、纤维植物104种、油脂植物76种、观赏植物74种、野果植物54种、芳香植物54种、树脂树胶植物68种、淀粉及糖类植物52种,鞣科植物32种、珍稀植物49种、其它类型植物465种。论述了三峡库区资源植物的分类及保护现状。     

Phylogeographic patterns in Hypochaeris section Hypochaeris (Asteraceae, Lactuceae) of the western Mediterranean

Aim  To analyse phylogeographic patterns in the four species of Hypochaeris sect. Hypochaeris , evaluating possible areas of origin and the microevolutionary processes that have shaped their morphology, genetics and distribution.
Location  Western Mediterranean area.
Methods  We applied amplified fragment length polymorphism (AFLP) markers to a total of 494 individuals belonging to 82 populations of Hypochaeris arachnoidea , H. glabra , H. radicata and H. salzmanniana to determine population structure.
Results  Populations with the largest proportion of private and rare AFLP fragments were found in Morocco. This region was consequently inferred to be the ancestral area for H. arachnoidea , H. glabra , H. radicata and H. salzmanniana . The Guadalquivir River (southern Spain) was inferred to be an effective dispersal barrier for H. glabra and H. radicata. The Strait of Gibraltar was inferred to be a somewhat weaker barrier than the Guadalquivir River for H. radicata and a much weaker barrier for H. glabra . The main barrier for H. salzmanniana coincides with the extension of the Rif Mountains to the Atlantic coast in Morocco, and the Strait of Gibraltar is a much weaker barrier for this species. Hypochaeris arachnoidea appears to have originated in the Atlas Mountains.
Main conclusions  The highest levels of genetic variation in La Mamora forest ( H. glabra and H. salzmanniana ) or the adjacent central Middle Atlas ( H. arachnoidea and H. radicata ) in Morocco suggest that these areas were a centre of origin of Hypochaeris sect. Hypochaeris . All three potential barriers – the Guadalquivir River, the Strait of Gibraltar, and the Rif Mountains – have been important in shaping genetic diversity in species of section Hypochaeris .     

Site prioritisation for the protection of rare subterranean species – the cases of two ostracods from south-western France

1. Delineation of protected areas for rare subterranean species is a key problem for groundwater biodiversity conservation, because of practical difficulties in implementation. Criteria for site selection are presented that are derived from studies on two remarkable Ostracoda, Dolekiella europaea Gidó, Artheau, Colin, Danielopol & Marmonier (Limnocytheridae) and Vestalenula carveli Artheau (Darwinulidae) discovered in south-western France.
2. Arguments for natural heritage value and protection of subterranean species are proposed and illustrated by using information on these two ostracod species. The proposed criteria are: (i) local and/or regional endemism; (ii) known occurrence of the species at a few localities only; (iii) representativeness for ancient phylogenetic lineages with wider geographical distributions in the past; and (iv) suitability for scientific study because of unique morphological or biological traits.
3. It is also proposed to prioritise the protection of subsurface sites using the following criteria: (i) type locality for newly described species; (ii) presence of other rare stygobiotic taxa; and (iii) high population densities of the primary target species.
4. Development and implementation of protection strategies at local scale are likely to benefit from collaboration between scientists, policy makers and stakeholders. The measures taken should complement existing national and/or international attempts at large-scale protection of groundwater biodiversity.     

广西苦苣苔科稀有珍贵植物——弥勒苣苔

首次报道广西苦苣苔科植物一新记录属:弥勒苣苔属.该属接近金盏苣苔属,但不同在于弥勒苣苔属花冠上唇4浅裂,下唇不分裂,2对雄蕊分别着生于花冠中部及其上方,雌蕊具一个柱头.弥勒苣苔属为中国特有的单型属,仅弥勒苣苔一种,分布于云南东南部和广西西部.该种在广西首次记录,凭证标本存放于广西植物标本馆(IBK).     

一株可同时降解多种高环PAHs的丝状真菌——宛氏拟青霉(Paecilomyces variotii)

采用液体培养的方法,分离纯化了丝状真菌宛氏拟青霉(Paecilomyces variotii)并研究了其对苯并[a]蒽、苯并[a]芘、苯并[b]荧蒽、苯并[k]荧蒽、茚并[1,2,3-cd]芘的降解效果.结果表明:接种处理30 d,该菌株对混合体系中5种PAHs的降解率为16.1%～24.6%,而对单一体系中的降解率为10.4%～33.3%;同时,对单一与混合体系中PAHs的降解作用存在一定差异,苯并[k]荧蒽和苯并[b]荧蒽在单一体系中降解率增大,而其他种类的则减小.本研究结果为高环多环芳烃共代谢机理研究和多环芳烃复合污染水土环境的生物修复提供了一种新的种质资源.     

Linking Geographical Information Systems and Observational and Experimental Studies to Determine Optimal Seedling Microsites of an Endangered Plant in a Subtropical Urban Fire‐Adapted Ecosystem

Understanding microsite requirements is critical for restoring sustainable rare plant populations and creating meaningful management plans that will enhance native species’ population viability. Natural areas bordered by urban communities have restricted size and constrained management options that confound goals of preserving biodiversity. Using geographical information systems and observational and experimental studies, we determined that current microsites required for seedling establishment within existing habitat of the federally endangered Crenulate leadplant are few and spatially restricted, resulting in little wild seedling recruitment. Experimental and wild seedlings had highest germination rates in litter layers 1–2 cm in depth and survived the longest in litter 0.5–2 cm deep. Fire suppression and aggressive native and exotic plants have accumulated litter up to 33 cm near some of the wild adult Crenulate leadplant. Only 9% of habitat occupied by this taxon at its largest population is conducive to seedling establishment. Similarly, 30% is conducive to seedling establishment in the second largest population. Fire plays a critical role in South Florida ecosystem dynamics and the restoration and preservation of its landscape and biodiversity. When fire is not possible, other management is needed. Manual litter and downed debris removal are recommended at both population sites to improve the probability of Crenulate leadplant seedling establishment and population persistence.     

Floristic composition and conservation value of the stubble-field weed community,dominated by <Emphasis Type="Italic">Stachys annua</Emphasis> in western Hungary

The stubble-field weed community, dominated by Stachys annua, was generally distributed in Hungary until the 1950s on mid-heavy and heavy, base-rich soils. Stachys annua is an excellent nectar-producer, and from the nectar collected in its habitats popular stubble-honey was produced. This vegetation type has suffered significant decline, mainly due to the early ploughing of stubbles associated with the intensification of agriculture. In the present study, the floristic composition of this community is assessed based on 213 phytosociological records, and its distribution in the past ten years in western Hungary is mapped. Sixty-five percent of the species are of Eurasian, European and Mediterranean elements, and the largest proportion of the species are spring-germinating summer annuals. The proportion of insect-pollinated plant species is approximately 70%, and the species composition also offers significant seed food sources for farmland birds, e.g. Coturnix coturnix and Perdix perdix. Therefore this community should deserve a high conservation priority for biodiversity. The factors that offer the greatest threats to the continuing existence of this community type are intensive agricultural management and the increasing spread of Ambrosia artemisiifolia.     

Tandem Stop Codons in Ciliates That Reassign Stop Codons

Tandem stop codons are extra stop codons hypothesized to be present downstream of genes to act as a backup in case of read-through of the real stop codon. Although seemingly absent from Escherichia coli, recent studies have confirmed the presence of such codons in yeast. In this paper we will analyze the genomes of two ciliate species—Paramecium tetraurelia and Tetrahymena thermophila—that reassign the stop codons TAA and TAG to glutamine, for the presence of tandem stop codons. We show that there are more tandem stop codons downstream of both Paramecium and Tetrahymena genes than expected by chance given the base composition of the downstream regions. This excess of tandem stop codons is larger in Tetrahymena and Paramecium than in yeast. We propose that this might be caused by a higher frequency of stop codon read-through in these species than in yeast, possibly because of a leaky termination machinery resulting from stop codon reassignment.     

Volatile leaf oil diversity in the narrow range endemic Eucalyptus argutifolia (Myrtaceae) and its widespread congener Eucalyptus obtusiflora

Variation in the qualitative composition of volatile leaf oil was examined in the rare Eucalyptus argutifolia and its widespread congener Eucalyptus obtusiflora . The results revealed that, consistent with the pattern seen with allozymes, E. argutifolia had less variation within populations than E. obtusiflora . Total leaf oil diversity was also significantly lower in the rare species. As found with allozymes, most leaf oil diversity was within populations, but there was also a significant proportion of the variation between populations (25.2% and 27.3% for E. argutifolia and E. obtusiflora , respectively). There were significant associations between phenotypic distance based on leaf oils and geographical distance and between phenotypic and genetic distance across all populations, but these associations were not evident within species. Factors leading to reduced variation in E. argutifolia appear to affect all types of variation, but the relationships between different types of variation within the species are less apparent.  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 96 , 738–745.     

Level of habitat fragmentation determines its non-linear relationships with plant speciesn richness,frequency and density at desertified grasslands in Inner Mongolia,China

Aims This study aimed to examine the changes in plant species richness, frequency and density along a habitat fragmentation gradient (with varied degrees of habitat fragmentation [DHFs]) in a desertified grassland of Horqin Sandy Land, northeastern Inner Mongolia, China.