Mitochondrial cytochrome b sequence variations and phylogeny of the East Asian bagrid catfishes

The mitochondrial DNA cytochrome b gene was sequenced from 8 bagrid catfishes in China. Aligned with cytochrome b sequences from 9 bagrid catfishes in Japan, Korea and Russia retrieved from GenBank, and selected Silurus meridionalis, Liobagrus anguillicauda, Liobagrus reini and Phenacogrammus interruptus as outgroups, we constructed a matrix of 21 DNA sequences. The Kimura's two-parameter distances were calculated and molecule phylogenetic trees were constructed by using the maximum parsimony (MP) and neighbor-joining (NJ) methods. The results show that (i) there exist 3-bp deletions of mitochondrial cytochrome b gene compared with cypriniforms and characiforms; (ii) the molecular phylogenetic tree suggests that bagrid catfishes form a monophyletic group, and the genus Mystus is the earliest divergent in the East Asian bagrid catfishes, as well as the genus Pseudobagrus is a monophyletic group but the genus Pelteobagrus and Leiocassis are complicated; and 60 the evolution rate of the East Asian bagrids mitochondrial cytochrome b gene is about 0.18%-0.30% sequence divergence per million years.

Mechanism for Giycinebetaine to Improve Plant Salt Resistance and Its Research Advances in Genetic Engineering

The paper systematically discusses the mechanism for glycinebetaine to improve plant salt resistance and its research advances in genetic engineering at home and abroad as well as summarizing the research progresses about the key enzymes and their genetic engineering in glycinebetaine biosynthesis. It suggests that on the basis of further understanding the mechanism for glycinebetaine to improve plant salt resistance,the transformation of the genes relating to glycinebetaine biosynthesis should be carried out in major crops so that new plant varieties resistant to salt can be obtained.

Effects of altitude on plant-species diversity and productivity in an alpine meadow, Qinghai-Tibetan plateau

During the growing seasons of 2002 and 2003, biomass productivity and diversity were examined along an altitudinal transect on the south-western slope of Beishan Mountain, Maqin County (33 degrees 43'-35 degrees 16'N, 98 degrees 48'-100 degrees 55'E), Qinghai-Tibetan Plateau. Six altitudes were selected, between 3840 and 4435 m. Soil organic matter, soil available N and P and environmental factors significantly affected plant-species diversity and productivity of the alpine meadows. Aboveground biomass declined significantly with increasing altitude (P < 0.05) and it was positively and linearly related to late summer soil-surface temperature. Belowground biomass (0 - 10-cm depth) was significantly greater at the lowest and highest altitudes than at intermediate locations, associated with water and nutrient availabilities. At each site, the maximum belowground biomass values occurred at the beginning and the end of the growing seasons (P < 0.05). Soil organic matter content, and available N and P were negatively and closely related to plant diversity (species richness, Shannon-Wiener diversity index, and Pielou evenness index).

Variation in mitochondrial DNA and phylogeny of six species of pikas (Ochotona)

Phylogenetic relationships of six species of Ochotona were investigated using mitochondrial DNA (mtDNA) restriction-site analysis. The phylogenetic tree constructed using PAUP was based on 62 phylogenetically informative sites with O. erythrotis designated as an outgroup. Two clades were evident. One contained O. curzoniae, O. huangensis, and O. thibetana. in the second, O. daurica was a sister taxon of O. cansus. The five species appear to come from different maternal lineages. The branching structure of the tree and sequence divergence confirm that huangensis and cansus are distinct species, and that mol-osa is a synonym of O. cansus rather than O. thibetana. Divergence time, estimated from genetic distances, indicates that the ancestors of the two maternal lineages diverged ca. 6.5 x 10(6) years ago. O. curzoniae diverged from O. huangensis, and O. daurica diverged from O. cansus, at about the same time (ca. 3.4 x 10(6) years ago). These data suggest a period of rapid radiation of the genus Ochotona in China, perhaps during the late Pliocene. These calculations correspond roughly to tectonic events and environmental changes in China throughout this period, and appear to be substantiated by the fossil record.

茸卷象属（Coleoptera：Attelabidae）分类与系统发育研究及寄主识别机制初探

本文选取卷叶象甲科昆虫为研究对象，以形态分类学为基础，辅之以分子生 物学手段，对中国特有的茸卷象属（Euscelophilus）进行了系统发育学的研究。 并在此基础上，对该属昆虫进行了亚显微结构的研究，该研究不仅对其分类学观 点进行了验证，对属内分种的有效形态学性状进行了补充，而且从感受器亚显微 形态的角度讨论了卷象与寄主植物的化学识别机制，明晰了其结构基础。最后， 本文首次从力学角度对卷象与其寄主植物的物理识别机制进行了探讨。 在分类学研究中，本文首先整理了中国卷叶象甲鉴定科、亚科、族、属的检 索表，同时对其中的18 个常见属的分种检索表进行了整理，并对其中中国特有 属Euscelophilus 进行了深入的分类学研究。将Euscelophilidius、Cureuscelophilus 两属和Euscelophiloides 亚属定义为Euscelophilus 的新异名，并提供了该属物种 检索表，同时为该属新增三个物种，分别是Euselophilus longispinus Xie & Liang, sp. n.，Euselophilus gaoligongensis Xie & Liang, sp. n.和Euselophilus caperratus Xie & Liang, sp. n.，并对两物种E. denticulatus 和 E. gibbicollis 的雄性外生殖器 进行了描绘。 分子生物学研究以该属内9 种和4 个外群种共23 个个体为材料，对其COII 基因进行了扩增，并对所得的核苷酸序列使用PAUP 和贝叶斯两种方法构建分子 系统发育树。结果表明，中国茸卷象属是一个单系群，其内部可分为三支，分别 以E. niger，E. gibbicollis 和E. rugolosus 为代表，建议将该属分为三个亚属，对 于该属有争议的物种T. (E.) qinni，依照本研究获得的数据，建议将其移回 Euscelophilus 属。亚显微结构研究选取本属内8 个物种作为研究对象，分别对其头部、胸部、 腹部及前足的形态性状，使用扫描电子显微镜进行了观察拍照。同时，选取了复 眼、触角、下唇须、外颚叶、腹部、跗节等部位分布的各种感受器进行了亚显微 结构的研究。结果表明，形态相似的近缘物种在亚显微结构上可显示出更大的形 状差异，同时，首次证明额的形态特征可作为该属内分种的有效依据。感受器结 构研究表明卷象识别寄主植物的主要感受器为毛状、锥状、乳突状化学感受器， 其次为刺状、毛状的听觉（物理）感受器以及六棱形小眼组成的视觉感受器（复 眼）。 力学研究部分选取Apoderus 属一种卷象及其寄主植物马桑（Coriaria nepalensis Wall.）为研究对象，首先以人工模拟卷叶的形式对卷象卷叶所需的力 进行了分析，其次以纳米压痕手段对卷象上颚和马桑叶片的硬度和弹性模量分别 进行了研究。结果表明，先切叶后卷叶是更省力更进化的卷叶模式，同时卷象选 择寄主植物的机制中，两者的物理性能呈一定的相关性。

中国鸟类的DNA分类及系统发育研究概述

鸟类分类是鸟类学其他研究领域的基础,近年来分子技术的发展,以及计算机技术的应用为鸟类分类学和鸟类系统演化研究提供了新的研究手段,给传统的系统分类研究带来了新的机遇.Tautz等于2002年首先提出运用DNA序列作为生物分类系统的主要平台,即DNA分类学(DNA Taxonomy).而Hebert等于2003年则首次提出了DNA条形码(DNA Barcoding)的概念,并对其物种分类和鉴定意义予以肯定,建议利用线粒体细胞色素C氧化酶亚单位Ⅰ(COI)的特定区段来做DNA条形编码的基础.在鸟类DNA分类方面,国内学者应用线粒体基因Cut b,COI,c-mos,c-myc,12s rRNA,16s rRNA,ND2,ND3,CR,RAG-1以及核基因myoglobin introⅡ等不同片段对很多类群进行了分类探讨和系统发育研究.但是主要集中在鸡形目及雀形目鸟类.中国是鸟类多样性极其丰富的国家,近年来很多亚种、种及以上分类阶元依然存在问题,因此,中国鸟类物种的分类地位、系统发育与演化关系等依然有很多问题等待深入研究.目前国内基于COI的鸟类分类及系统发育研究有了一些报道,但是真正的DNA条形码工作尚需继续、深入地开展.

中国扇肢亚目(甲壳动物:等足目)的系统分类学研究

该文以传统的形态分类为主,结合现代分类学的手段和方法解决近似种、疑难种的准确鉴定问题,搞清中国的属种及分类上存在的错误和混淆,并结合已有的此类群研究结果,进行地理区系的比较.该文记述了中国扇肢亚目7科37属81种,其中包括13个新种,29种为中国海域新记录种.该文描述了所有属种,提供了形态结构图,对中国易混淆的常见种类就其形态、构造等方面作了比较研究;提供了各属种的系统检索表,对有用的分类依据进行了讨论并概述了生态习性和自然历史.该文对扇肢亚目的7个科进行了系统发育分析,创建了系统进化树,分析了各科间的亲缘关系.地理分布研究得出,中国特有种18种,与日本共有种为24种,其中仅中国-日本共有种为11种,说明中国与日本的区系较大的相似性.中国南海种数显著超过东海及黄渤海,显示了由北至南,种数逐渐增多的分布规律.

Phylogeny of Oedogoniales (Chlorophyceae, Chlorophyta) inferred from 18S rDNA sequences with emphasis on the relationships in the genus Oedogonium based on ITS-2 sequences

The phylogeny of Oedogoniales was investigated by using nuclear 18S rDNA sequences. Results showed that the genus Oedocladium, as a separated clade, was clustered within the clade of Oedogonium; whereas the genus Bulbochaete was in a comparatively divergent position to the other two genera. The relationship among the species of Oedogonium was discussed, focusing on ITS-2 phylogeny analyzed combining with some morphological characteristics. Our results showed that all the dioecious nannandrous taxa involved in this study were resolved into one clade, while all the monocious taxa were clustered into another clade as a sister group to the former. The report also suggests that the dioecious macrandrous taxa form a paraphyly and could be more basally situated than the dioecious nannandrous and the monoecious taxa by means of molecular phylogeny and morphotype investigations.

Interannual fluctuations in floral longevity, pollinator visitation and pollination limitation of an alpine plant (Gentiana straminea Maxim., Gentianaceae) at two altitudes in the Qinghai-Tibetan Plateau

Prolonged floral longevity and bumblebees as dominate pollinators in alpine ecosystem have been suggested to overcome pollination limitation of alpine plants arising from the decrease of pollinator activity with increasing altitude. However, this conclusion has never been examined in the Qinghai-Tibetan Plateau (QTP), the highest and largest plateau in the world. In this study, we intended to test year-to-year correlations between floral longevity, visiting frequency and pollen limitation of this species between two populations (at 3200 m and 4000 m) of Gentiana straminea in this plateau. Pollinator exclusion elongated both male and female phases greatly at both sites, and durations of both male and female phases in natural condition varied greatly over three years. The visiting frequency of bumblebees varied greatly at the higher altitude, but seemed to be stable at the lower altitude. Seed production was pollination limited in both populations in most studied years. The floral durations, pollinator frequency and pollination limitation showed no significant and consistent variations with the increase of altitude. The previous hypothesis that the prolonged floral longevity of alpine plants can compensate for low levels of pollinator visitation therefore could not be confirmed, and our results further suggested that in the QTP platform, the altitude shows no consistent effect on the reproductive performance of this species, despite that the fluctuation of visit frequency intensified at the higher altitude.