Phenology of plants in relation to ambient environment in a subalpine forest of Uttarakhand,western Himalaya

Observations on phenology of some representative trees, shrubs, under-shrubs and herbs in a subalpine forest of Uttarakhand, western Himalaya were recorded. With the commencement of favorable growth season in April, occurrence of leaf fall was indicatory growth phenomenon in Quercus semecarpifolia, Q. floribunda and Abies spectabilis. However, active vegetative growth in herbaceous species starts onward April and fruit maturation and seed dehiscence are completed from mid of September to October. In general, vegetative growth and reproductive stages in majority of the studied species seems to be dependent on adequate moisture content and also flowering and fruiting in subalpine plants correlate ambient temperature.     

Q-NET – a new scholarly network on quantitative wood anatomy

Quantitative wood anatomy (QWA) is a dynamic research approach of increasing interest that can provide answers to a wide range of research questions across different disciplines. However, the lack of common protocols and knowledge gaps hinder the realisation of the full potential of QWA. Therefore, we established the new community-based network Q-NET to provide an open interdisciplinary platform for exchange and research around QWA. Q-NET (https://qwa-net.com) combines an online knowledge and exchange base with virtual workshops. The first two workshops each attracted more than 125 participants from around the world, demonstrating the community's interest in QWA and this virtual way of networking and collaborating. Indeed, virtual networks such as Q-NET could increase the inclusiveness, efficiency and sustainability of scientific collaboration while providing additional training and teaching opportunities for early career scientists, both of which complement in-person conferences and workshops.     

Biochemical,physiological and molecular characteristics of chickpea rhizobacteria from Kurdistan province,Iran

Kurdistan province of Iran is one of the main places for producing chickpea, and there is no published research on root-nodulating bacteria of this crop. Plant samples were collected and a total of 73 Rhizobium strains were isolated from root nodules. Nodulation test was done on chickpea plants. Phenotypic characteristics of the 16 representative strains were determined based on the standard bacteriological methods. Total soluble cell protein patterns by electrophoresis approach (SDS-PAGE) showed heterogeneity among the tested rhizobia strains. Based on the phenotypic features, Rhizobium strains of three groups belong to different species of the genus Mesorhizobioum including M. ciceri and M. mediterraneum and Mesorhizobium sp. The PCR technique was employed for amplification of 16S rDNA and atpD genes. For further characterisation, amplified fragment of 16S rDNA gene from a representative strain (AK21) using primers 41F and 1488R was subjected to sequencing. Sequences were aligned by BLAST software at NCBI GenBank and results showed 99% similarity with M. mediterraneum strain BKBCF3q.     

基于滑动窗口的原核转录起始位点计算定位方法

转录起始位点的计算定位是基因转录调控研究的重要内容,但现有方法的识别性能较低。文章作者在已有原核启动子识别算法的基础上,提出了一种基于滑动窗口的原核转录起始位点计算定位方法,通过在合理限定的定位范围内对序列进行滑动扫描,来预测转录起始位点的位置。首先根据窗口序列的交迭组分特征和启动子其它特征分别建立二次判别分类器,用其计算对应位置的似然得分,再利用转录起始位点与翻译起始位点的间隔经验分布信息对似然得分进行修正,最后依照似然得分的分布情况由阈值定位算法确定预测位置。对大肠杆菌真实序列数据的测试结果表明,该定位算法可实现对真实转录起始位点位置的有效预测,与已有算法相比,当敏感性指标同为0.85左右时,特异性指标可从0.20提高至0.65,从而使得定位准确率提高了约20个百分点。     

皇甫川流域中小型土壤动物对不同水土治理措施的响应

2007年9月至2008年9月,选择皇甫川流域人工松树林、人工杨树林、人工锦鸡儿灌木林、人工沙打旺草地和撂荒地等不同水土治理措施植被为采样地,以耕作农田为对照,研究了中小型土壤动物对不同水土治理措施的响应。结果表明,共捕获中小型土壤动物14 747只,隶属于5门7纲10类。优势类群为线虫,占群落总个体数的比例为95.53%,常见类群为螨类和弹尾类。不同水土治理措施样地中,中小型土壤动物群落个体数较农田有提高趋势,但无显著差异（P >0.05）;螨类和弹尾类个体数显著提高（P<0.05）;线虫个体数在人工沙打旺草地中显著高于农田（P<0.05）;中小型土壤动物垂直分布的表聚性较农田增强,并以地表凋落物覆盖显著的人工林最为明显。RDA分析表明,中小型土壤动物群落、螨类和弹尾类个体数与凋落物厚度、树（草）高和土壤有机质的变化之间呈显著正相关。以上结果说明,研究地区采取的几种水土治理植被均有利于中小型土壤动物群落的恢复;相比较,地表凋落物层显著的人工松树林、人工杨树林更加有益于螨类和弹尾类的恢复。     

A review of the allozyme data set for the Canarian endemic flora: causes of the high genetic diversity levels and implications for conservation

Background and Aims

Allozyme and reproductive data sets for the Canarian flora are updated in order to assess how the present levels and structuring of genetic variation have been influenced by the abiotic island traits and by phylogenetically determined biotic traits of the corresponding taxa; and in order to suggest conservation guidelines.

Methods

Kruskal–Wallis tests are conducted to assess the relationships of 27 variables with genetic diversity (estimated by A, P, H_o and H_e) and structuring (G_ST) of 123 taxa representing 309 populations and 16 families. Multiple linear regression analyses (MLRAs) are carried out to determine the relative influence of the less correlated significant abiotic and biotic factors on the genetic diversity levels.

Key Results and Conclusions

The interactions between biotic features of the colonizing taxa and the abiotic island features drive plant diversification in the Canarian flora. However, the lower weight of closeness to the mainland than of (respectively) high basic chromosome number, partial or total self-incompatibility and polyploidy in the MLRAs indicates substantial phylogenetic constraint; the importance of a high chromosome number is feasibly due to the generation of a larger number of linkage groups, which increase gametic and genotypic diversity. Genetic structure is also more influenced by biotic factors (long-range seed dispersal, basic chromosome number and partial or total self-incompatibility) than by distance to the mainland. Conservation-wise, genetic structure estimates (F_ST/G_ST) only reflect endangerment under intensive population sampling designs, and neutral genetic variation levels do not directly relate to threat status or to small population sizes. Habitat protection is emphasized, but the results suggest the need for urgent implementation of elementary reproductive studies in all cases, and for ex situ conservation measures for the most endangered taxa, even without prior studies. In non-endangered endemics, multidisciplinary research is needed before suggesting case-specific conservation strategies. The molecular information relevant for conservation should be conserved in a standardized format to facilitate further insight.     

Potential distribution of vulnerable Entandrophragma angolense (Welw.) C. DC. (Meliaceae) in East Africa

The various human‐induced threats imposed on nature have recently triggered the study of species' distributions. We developed potential suitability models using two algorithms for a threatened African mahogany, Entandrophragma angolense, in three East African countries; Kenya, Tanzania and Uganda. The effect of features selection and modelling algorithm selection on potential suitability predictions was explored. Occurrence records and high‐resolution environmental data were used. The two species distribution modelling techniques were genetic algorithm rule for prediction; and maximum entropy modelling. With Maxent, the area under the receiver characteristic operating curve (AUC) for potential distribution models tested on independent data ranged from 0.942 to 0.972 when using automatic features and from 0.974 to 0.666 with target or specific features. With GARP, AUC for potential distribution models ranged from 0.591 to 0.736 with all rule types and from 0.388 to 0.805 for specific rule types (Tables  1  and 2 ). The area under the E. angolense potential suitability was best predicted by soil, rainfall and aspect using GARP. Potential suitability increased with increasing aspect and decreased with increasing slope. Low rainfall and elevation increased potential suitability, while high levels of either variable decreased potential suitability. Potential suitability maps for vulnerable species require using a multi‐algorithm, fine scale data approach and incorporation of environmental variables like soil, slope, land use and elevation. Species distribution models can offer insight on the distribution requirements of vulnerable species and help guide the development of management plans. Results of this study suggest that E. angolense management plans should promote the protection of terrestrial forests surrounding water bodies including Mabira forest in Uganda.