叶下珠科珠子木属一新异名

岩生珠子木(Phyllanthodendron petraeum P. T. Li)和圆叶珠子木(P. orbicularifolium P. T. Li)均为中国广西壮族自治区特有种,二者曾被认为基于叶片质地与形状、叶脉特征、花盘腺体形状以及花柱开裂程度等一系列形态特征可进行区分,然而基于近年来查阅大量标本和野外考察工作认为二者实为同种,故在此将后者处理为前者的异名。     

An unusual glucoside from Cleistanthus gracilis

Extraction of roots and stems of Cleistanthus gracilis furnished common triterpenes, plant sterols and the unusual glucoside (+) gracicleistanthoside, the glucoside of 2-beta-hydroxy-8-azabicyclo-(5,2,0)-4beta,9beta-epoxynona-5,7-diene.     

中国算盘子属(叶下珠科)果实形态特征及其分类学意义

算盘子属是一个分类较为困难的大类群,全世界超过300种,其中众多物种间的界定至今颇存争议。本研究在野外考察及对馆藏标本查阅的基础上,对中国算盘子属21种1变种的果实形态进行了仔细观察和研究。结果显示,该属物种果实被毛情况、果实大小、宿存花柱、纵沟深浅和数目等形态特征在种间具有很高的多样性,可用于对不同物种的鉴别,具有一定的分类学价值。基于果实形态特征提供了这21种1变种的分类检索表。     

叶下珠头细蛾与小果叶下珠互利共生的研究--生物学及系统稳定性

【目的】为了确定小果叶下珠 Phyllanthus microcarpus 与叶下珠头细蛾 Epicephala sp.之间专性互利共生系统稳定性的增强是否主要通过彼此之间相互遏制对方对自身进行过度开采。【方法】通过对小果叶下珠上共生的叶下珠头细蛾形态及生物学的研究,记述了叶下珠头细蛾专性寄生寄主植物时的行为特性及共生双方利益得失。【结果】叶下珠头细蛾在广西一年两代,成虫的羽化数量与寄主植物雌雄花总数峰值变化同步;幼虫对小果叶下珠果实的寄生率为96%,单个果实内幼虫寄生数量＞1,但平均每个果实内被取食的种子为56.9%,叶下珠头细蛾低龄幼虫相对较高的死亡率限制了其对寄主种子的过度取食;果实内种子的适度保留和低龄幼虫的高死亡率是小果叶下珠-叶下珠头细蛾互利共生体系维持稳定的关键因素。【结论】小果叶下珠的表型性状出现了趋异性进化,叶下珠头细蛾与不同表型的小果叶下珠均有互利共生关系。因此,对叶下珠头细蛾形态及生物学进行详细研究有助于深入了解小果叶下珠与头细蛾共生体系物种组成多样性及进化生物学,并为探讨大戟科植物同头细蛾属昆虫协同互利共生多样性形成原因提供依据。     

Mutualism favours higher host specificity than does antagonism in plant–herbivore interaction

Coevolved mutualisms often exhibit high levels of partner specificity. Obligate pollination mutualisms, such as the fig–fig wasp and yucca–yucca moth systems, represent remarkable examples of such highly species-specific associations; however, the evolutionary processes underlying these patterns are poorly understood. The prevailing hypothesis suggests that the high degree of specificity in pollinating seed parasites is the fortuitous result of specialization in their ancestors because these insects are derived from endophytic herbivores that are themselves highly host-specific. Conversely, we show that in the Glochidion–Epicephala obligate pollination mutualism, pollinators are more host-specific than are closely related endophytic leaf-feeding taxa, which co-occur with Epicephala on the same Glochidion hosts. This difference is probably not because of shifts in larval diet (i.e. from leaf- to seed-feeding), because seed-eating lepidopterans other than Epicephala do not show the same degree of host specificity as Epicephala. Species of a tentative sister group of Epicephala each attack several distantly related plants, suggesting that the evolution of strict host specificity is tied to the evolution of pollinator habit. These results suggest that mutualists can attain higher host specificity than that of their parasitic ancestors and that coevolutionary selection can be a strong promoter of extreme reciprocal specialization in mutualisms.     

Revision of <Emphasis Type="Italic">Heterosavia</Emphasis>, stat. nov., with notes on <Emphasis Type="Italic">Gonatogyne</Emphasis> and <Emphasis Type="Italic">Savia</Emphasis> (Phyllanthaceae)

Heterosavia (Phyllanthaceae) is segregated from Savia (tribe Bridelieae), recognized at generic rank, and placed in tribe Phyllantheae. Floral, fruit, leaf anatomical, leaf venation, and pollen characters of the neotropical taxa previously united as Savia including Gonatogyne are discussed and illustrated. Keys to the three genera and to the species of Heterosavia are presented. Four species (all new combinations), Heterosavia bahamensis, H. erythroxyloides, H. laurifolia, and H. maculata, are recognized. The new combinations Heterosavia laurifolia var. intermedia and H. maculata var. clementis are proposed. The names Heterosavia, H. erythroxyloides, H. laurifolia, Savia clementis, S. clusiifolia, S. clusiifolia var. fallax, and S. longipes are lectotypified. Distribution maps and conservation assessments (IUCN ratings) of Heterosavia species and varieties are provided.     

Spatial structure and the effects of host and soil environments on communities of ectomycorrhizal fungi in wooded savannas and rain forests of Continental Africa and Madagascar

Mycorrhizal fungi play a key role in mineral nutrition of terrestrial plants, but the factors affecting natural distribution, diversity and community composition of particularly tropical fungi remain poorly understood. This study addresses shifts in community structure and species frequency of ectomycorrhizal (EcM) fungi in relation to host taxa, soil depth and spatial structure in four contrasting African ecosystems. We used the rDNA and plastid trnL intron sequence analysis for identification of fungi and host plants, respectively. By partitioning out spatial autocorrelation in plant and fungal distribution, we suggest that African EcM fungal communities are little structured by soil horizon and host at the plant species and family levels. These findings contrast with patterns of vegetation in these forests and EcM fungal communities in other tropical and temperate ecosystems. The low level of host preference indirectly supports an earlier hypothesis that pioneer Phyllanthaceae may facilitate the establishment of late successional Fabaceae and potentially other EcM host trees by providing compatible fungal inoculum in deforested and naturally disturbed ecosystems of tropical Africa.     

白毛算盘子(叶下珠科)在中国无分布

长期以来,白毛算盘子(Glochidion arborescens Blume)被认为广布于中国云南西部至南部地区。该研究基于多年野外考察及标本查阅工作发现,由于白毛算盘子在中国的分布实为标本错误鉴定所致,相关错误鉴定的标本绝大部分属于绒毛算盘子 [G. heyneanum(Wight & Arn.)Wight],少部分属于里白算盘子(G. acuminatum var. acuminatum Müll. Arg.)、毛果算盘子(G. eriocarpum Champ. ex Benth.)、艾胶算盘子 [G. lancolarium(Roxb.)Voigt]或厚叶算盘子 [G. zeylanicum var. tomentosum(Dalzell)Trimen]等物种,故在此将白毛算盘子在中国的分布予以排除。另外,对白毛算盘子进行了后选模式指定,并提供了白毛算盘子与相关混淆种的物种检索表。     

头细蛾专性授粉体系中区域性共生多样化研究

头细蛾属昆虫与叶下珠科植物互利共生体系中头细蛾复合体的区域性物种组成的具体情况是互利共生多样性研究模型选取的重要参考指标。本研究通过对全世界头细蛾属昆虫与叶下珠科植物协同进化体系中非一对一互利共生关系进行系统的整理,并对小果叶下珠Phyllanthus microcarpus、黑面神Breynia fruticosa、圆果算盘子Glochidion sphaerogynum、革叶算盘子Glochidion daltonii 4种植物相关的互利共生模式在不同分布区头细蛾物种成分以及种群动态进行研究。结果显示:在广西小果叶下珠居群上共生3种头细蛾,这3种头细蛾在同年的第一个世代只出现2种,在云南和海南小果叶下珠上全年只发现2种,而在广州目前饲养的头细蛾成虫更是仅有叔头细蛾1种;革叶算盘子在云南和四川有2种共生头细蛾,而在广西和海南均仅有1种;在海南和厦门黑面神与喙果黑面神共享2种头细蛾,而在广西和广东黑面神上仅发现1种头细蛾;圆果算盘子是目前发现共生头细蛾物种最复杂的寄主植物,在海南记载有4种头细蛾,但在云南圆果算盘子上仅发现优头细蛾1种。4种寄主植物相关的互利共生体系中头细蛾物种组成在不同的分布地均发生了不同程度的区域性共生多样化,甚至在同一地区的不同世代之间也存在着头细蛾物种数量的变化,这对于深入理解具有互利共生关系的物种间协同进化多样性形成机制具有重要的意义。