Environmental effects on Neotropical liana species richness

Aim Lianas differ physiologically from trees, and therefore their species‐richness patterns and potential climate‐change responses might also differ. However, multivariate assessments of spatial patterns in liana species richness and their controls are lacking. Our aim in this paper is to identify the environmental factors that best explain the variation in liana species richness within tropical forests. Location Lowland and montane Neotropical forests. Methods We quantified the contributions of environmental variables and liana and tree‐and‐shrub abundance to the species richness of lianas, trees and shrubs ≥ 2.5 cm in diameter using a subset of 65 standardized (0.1 ha) plots from 57 Neotropical sites from a global dataset collected by the late Alwyn Gentry. We used both regression and structural equation modelling to account for the effects of environmental variables (climate, soil and disturbance) and liana density on liana species richness, and we compared the species‐richness patterns of lianas with those of trees and shrubs. Results We found that, after accounting for liana density, dry‐season length was the dominant predictor of liana species richness. In addition, liana species richness was also related to stand‐level wood density (a proxy for disturbance) in lowland forests, a pattern that has not hitherto been shown across such a large study region. Liana species richness had a weak association with soil properties, but the effect of soil may be obscured by the strong correlation between soil properties and climate. The diversity patterns of lianas and of trees and shrubs were congruent: wetter forests had a greater species richness of all woody plants. Main conclusions The primary association of both liana and tree‐and‐shrub species richness with water availability suggests that, if parts of the Neotropics become drier as a result of climate change, substantial declines in the species richness of woody plants at the stand level may be anticipated.     

Growth habit and mechanical architecture of the sand dune-adapted climber Clematis flammula var. maritima L

Clematis flammula var. maritima is a woody lianoid plant that grows on coastal sand dunes in the Mediterranean region. Older perennial stems are present as extensive underground axes. These generate surface growth of shorter-lived stems producing monospecific trellises above the surface of the sand. Despite its sand dune habitat and shortage of host support plants, this variety of Clematis shows mechanical characteristics during growth that are closely comparable with those of scandent woody lianas. A significant decrease in the value of structural Young's modulus is observed from the aerial trellis-forming shoots (1.619 +/- 0.492 GN m(-2)) to emergent axes (0.855 +/- 0.253 GN m(-2)) and underground woody stems (0.470 +/- 0.113 GN m(-2)). Biomechanical and developmental observations indicate that most emergent branches are optimized geometrically and mechanically in relation to their points of emergence from the sand, with increases in structural Young's modulus and the second moment of area around the surface of the sand. Lianoid plants, physiologically capable of withstanding sand dune environments, might represent acceptable natural or introduced species for dune stabilization and conservation.     

中国种子植物区系中的藤本多样性

藤本植物是植被的重要组成部分,但由于野外考察中物种及无性系分株鉴定的困难,长期以来在生态学研究中常常被忽视。为揭示中国藤本植物的多样性和特有性,作者研究了其科属组成、区系成分和攀援方式。结果显示:中国藤本植物种类丰富,共计有85科409属3,073种(含变种、亚种),占中国种子植物区系的11.3%;其中草质藤本898种,木质藤本2,175种,分别占中国种子植物区系的3.3%和8.0%。中国藤本植物区系热带成分显著,热带分布科和属分别占总科数或总属数(不含世界广布科属)的87.9%和79.2%;有14个含藤属为中国所特有,但没有特有含藤科。中国藤本植物最主要的攀援方式是缠绕类,占藤本植物总数的56.7%;其次为蔓生类和卷须类,分别占22.1%和17.0%;吸附类藤本种类最少,只占4.2%。     

南岳衡山藤本植物资源特点及其应用

调查分析湖南省南岳衡山藤本植物资源的特性与现状。该区野生藤本植物资源丰富,共有59科129属282种,大多具有重要的观赏与经济价值,主要有药用、食用、饲用、纤维、观赏等几大类;探讨了藤本植物在立体绿化中的应用方式与类型,并对今后开发利用野生藤本植物资源提出建议。     

贵州梵净山自然保护区藤本植物攀援方式及类型的研究

研究了梵净山自然保护区藤本植物的攀援方式及类型。从生物学、生态学角度 ,将梵净山藤本植物依照它们附着于支持物的攀登方法不同而划分为缠绕、攀援、卷须、根系、铺展与匍匐、寄生及兼有 2种以上攀援方式等 7大类型 14个亚型。并对该林区主要植被类型中的藤本植物进行了相应的讨论     

Liana community and functional trait analysis in tropical dry evergreen forest of India

Aim Lianas are abundant and diverse throughout the world and constitute an important structural and functional component of tropical forests. This study aims to investigate liana diversity, abundance and their functional traits in Indian tropical dry evergreen forest (TDEF).Methods A total of ten 1-ha plots, one each in 10 Indian TDEF sites were demarcated. Each 1-ha plot was divided into one-hundred 10- × 10-m quadrats to facilitate woody species inventory. All lianas ≥1cm diameter measured at 130cm from the rooting point and all trees ≥10-cm girth at breast height (gbh) were recorded from the study sites to analyze the patterns of liana diversity and abundance and also to compare the contribution of lianas to the total woody species richness, density and basal area. Liana variables across the study sites were compared using one-way analysis of variance. The qualitative functional traits of inventoried lianas and trees were assessed on the field and referring to pertinent field manuals.Important findings A total of 9237 liana individuals (ranged from 408–1658 individuals ha^-1) representing 52 species, 45 genera and 28 families were encountered from the 10 study sites. Liana species richness ranged from 11–31 species ha^-1 in 10 sites, which averaged 23.4 (±5.7) species ha^-1. The total basal area of lianas in the study sites was 7. 3 m 2 (0.20–1.76 m 2 ha^-1). There was a significant variation in liana species richness, density and basal area across the studied sites. On the whole, lianas contributed 52%, 49.3% and 4.1% to the total woody species (lianas and trees) richness, density and basal area, respectively. Liana trait analysis revealed the majority (50%) of lianas belonged to brevi-deciduous type. Stem twining was the chief climbing mechanism, exhibited by 21 species (52.6% of total abundance). More than half of the liana species (34 species; 6925 individuals) had microphyllous leaves. Fleshy-fruited lianas mostly bearing berries and drupes constituted the major fruit type in the studied sites. Zoochory was the predominant dispersal mode observed in 63.4% of species. Considering the ecological and functional role of lianas in Indian TDEF, the need for conservation is emphasized.     

广东省木质藤本植物地理成分及园林应用潜力分析

在对广东省木质藤本植物资源进行分析的基础上,结合对广州公园和校园的调查、统计,从区系地理学角度分析木质藤本的地理成分以及在园林应用中的潜力。结果显示,广东省木质藤本共有578种（含亚种、变种、栽培种和变型）,隶属于59科161属。其中,热带性科占总科数的71.12%,热带性属占总属数的81.99%,表明木质藤本的地理成分具有典型的热带性,这与广东省地处东亚季风气候特点相一致。乡土种531种,占91.87%,外来种47种,仅占8.13%,说明广东省木质藤本乡土植物种质资源非常丰富;但应用于广州园林中的木质藤本仅28科46属61种,其中乡土植物34种,外来植物27种,应用种类较少,园林应用潜力较大。建议在园林建设中通过增加优良种类的应用数量和提高应用频率,以及驯化观赏价值高的乡土种等途径来提高木质藤本的种类多样性和景观多样性。     

Multivariate analysis of leaf shape patterns in Asian species of the Uvaria group (Annonaceae)

Multivariate analysis of leaf radian measurements was used to investigate variation in leaf shape among 34 Asian species of the Uvaria group, a large palaeotropical group of climbing Annonaceae characterized by imbricate petals and stellate hairs. Raw data were normalized by conversion into 15 ratio characters and using the log₁₀ transformation. All species surveyed showed a unique leaf-shape 'bauplan'. The ratio character with the greatest discriminating power in both the Principal Components Analysis and Discriminant Analysis (DA) results was a measure of the shape of the leaf base. Ratio characters with the highest factor loadings for principal components 1 and 2 clearly separated the sampled taxa when plotted against one another and provided support for the retention of several taxa as distinct species or varieties. Classification of cases into taxa using DA yielded a correct classification rate of only 52% for the ratio-transformed data; however, division of taxa in the dataset into smaller subgroups defined by discrete morphological characters significantly increased the accuracy of case identification to between 67 and 100% of cases correctly classified, depending on the group. Case identification using DA on log₁₀-transformed data was higher than for the ratio values in the entire dataset (61.7%) and the larger subgroups. However, the rate of correct case assignment was lower in the smaller groups than for the ratio data.  © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society , 2003, 143 , 231–242.     

Factors influencing artemisinin production from shoot cultures of Artemisia annua L.

Artemisinin, an anti-malarial drug isolated from the annual wormwood Artemisia annua L., has a marked activity against chloroquine-resistant and chloroquine-sensitive strains of Plasmodium falciparum, and is useful in treatment of cerebral malaria. Shoot cultures of Artemisia annua L. were established on Murashige and Skoog basal medium which contained (per litre) 30 g sucrose, 0.5 mg 6-benzyladenine and 0.05 mg naphthaleneacetic acid. Using an optimized combination of sucrose (30 g/l), nitrate (45 mM), inorganic phosphate (200 mg/l), gibberellic acid (7 mg/l) and the ratio of NH₄ ⁺-N to NO₃ ^–-N of 1:3, artemisinin production reached 26.7 mg/l after 30 days. This procedure provides a potential alternative for production of artemisinin from in vitro tissue cultures.