河西走廊水资源问题的战略选择:建立节水型社会

 河西走廊水资源开发、利用中存在的突出问题是:水资源严重不足,供需矛盾突出;水资源的开发、利用大大超过了水资源的承载力;水资源配置不合理;水资源管理不科学,浪费现象严重;水利工程建设滞后,水资源利用率低;水质污染严重。在河西走廊建立节水型社会,应主要解决以下问题:改革水资源管理体制,实行水资源的统一管理;努力探索水资源市场化管理的途径;建立农民用水者协会参与式管理模式;大力调整农业产业结构,发展节水农业;加强节水水利工程建设,提高水资源利用率;控制污水排放,防止水质污染。     

Effectiveness of new agri-environment schemes in providing foraging resources for bumblebees in intensively farmed landscapes

Intensive farming has contributed to the serious declines in abundance and geographic range suffered by several bumblebee species in Europe and North America. Recent UK agri-environmental policy aims to conserve and restore bumblebee populations by providing foraging habitats on arable field margins. We examined the effectiveness of strategies to achieve this, including sowing seed mixtures of (1) tussocky grass species, (2) wildflowers and (3) pollen- and nectar-rich plants. These were compared to conventionally managed cereal crops. Sampling was undertaken in 32 10 × 10 km squares throughout England, each containing a sample of the different field margin types. Bumblebee abundance in July and August was significantly higher on pollen and nectar margins (86 ± 14 bees per 100 m) compared with wildflower margins (43 ± 14), mature grass margins (6 ± 14) and recently sown grass margins (8 ± 4). Bees were virtually absent from the cereal crop (0.2 ± 0.1). Bumblebee species richness was significantly higher on margins sown with either wildflowers or the pollen and nectar mix. There was evidence that richness of the bumblebee assemblage at the 10 × 10 km square scale was positively correlated with land use heterogeneity, the proportion of grassland, and the abundance and richness of dicotyledon flowers. The abundance of long-tongued bees per margin was explained by the number of pollen and nectar agreements per 10 × 10 km square, together with flower abundance. Future research is required to determine the quantity and location of foraging habitat required to sustain bumblebee populations at the landscape scale.     

循环经济作用机理探讨

从循环经济的内在本质、经济本质及其社会特征、核心作用和关键环节等角度,初步探讨了循环经济的作用机理。     

Genetic variation of the durum wheat landrace Haurani from different agro-ecological regions

The durum wheat landrace Haurani (Triticum durum Desf.) is grown under contrasting climatic regions of Syria from Deir Ezzor, in the North-East (230 m altitude, 150 mm mean annual rainfall), to Qunaytra, in the South-West (1060 m altitude, 825 mm mean annual rainfall). In order to assess the genetic variation between and within Haurani populations, samples from eight provinces of Syria (Daraa, Damascus, Qunaytra, Deir Ezzor, Hassakeh, Aleppo, Homs and Hama) were analysed by RFLPs and seed storage proteins of glutenin subunits as markers. The analyses showed the presence of genetic polymorphisms in all populations with the highest values in those from Homs and Hassakeh. Moreover, the results point out differences in genetic distances between populations; some populations were further apart, such as Damascus and Aleppo, whereas others were closer to each other, for instance Homs and Hama. Cluster analysis identified two distinct groups of populations, characterized by geographical proximity, with similar rainfall and altitude. It is suggested that the similarity of landraces at locations close to each other might be the result of more frequent seed exchanges between farmers or of gene flow due to 5% estimated outcross rate of Haurani.     

中国农业用水存在的问题及节水对策

水资源紧缺及社会工业化和城市化的发展导致中国农业水资源严重不足，与此同时，农业用水中的水浪费现象还普遍存在，因此，节水农业是解决中国缺水问题的唯一途径。该文分析了中国当前农业用水存在的主要问题，从农艺节水、抗旱品种选育以及农业用水管理创新等方面论述了目前国内外节水农业上的研究进展，并由此提出了中国进一步发展节水农业的战略性措施。     

Taxonomic status and geographic provenance of germplasm accessions in the Solanum nigrum L. complex: AFLP data

Amplified Fragment Length Polymorphisms (AFLPs) were employed within the taxonomically difficult Solanum nigrum L. complex in order to characterize the genetic diversity present in a collection of the Gatersleben Genebank, to classify taxonomically unknown material, and to correlate the clustering of the examined accessions with their geographic origin. The results from AFLP analyses using two primer combinations on 44 entries from five species led to the detection of four major clusters, simultaneously uncovering significant differences in the levels of genetic diversity within or between species. S. americanumexhibited the highest infraspecific variation despite close geographic origins, simultaneously being placed in a clearly separated cluster in comparison to the other examined species of the complex. In addition, these other species showed even less interspecific variation than was found at the infraspecific level in S. americanum. In terms of taxonomy, the application of AFLPs helped in the classification of 13 black nightshade accessions formerly only listed as Solanum sp. This also was confirmed by morphological determination. Furthermore, one accession formerly classified as S. physalifolium var. nitidibaccatum i) clustered with AFLPs and ii) was identified morphologically as S. villosum. Contradictory classifications remain for two further entries from the same species, found within the S. nigrum cluster after AFLP analyses, while belonging to S. physalifolium var. nitidibaccatum according to herbarium specimen. Finally, as indicated by the information on provenance in geographically separated subclusters in S. americanum and partially in S. villosum, clues on the currently unknown origin of accessions from the genebank seem feasible by AFLP data.     

Isozyme diversity and analysis of the mating system of the wild rice Oryza latifolia Desv. in Costa Rica

Oryza latifolia is the most abundant and widespread wild relative of rice in the lowlands of Costa Rica. It also has the most diverse morphology. However, little is known about the genetic diversity and mating system of this allotetraploid species. Genetic analyses of nine populations from different life zones from the Pacific and Atlantic slopes were performed using six isozyme loci. Differences in genetic variability were observed among populations, of which Palo Verde and Santa Rosa were the most diverse. Most Atlantic populations clustered together, and a similar result was obtained with the Pacific populations. High levels of interpopulation diversity were observed while most populations were monomorphic for at least one genotype, suggesting little genetic flow within populations. Even in polymorphic populations no variation was observed within progeny groups, combined with Hardy-Weinberg disequilibria in most populations, commonly observed in autogamous species or in species with clonal reproduction. However, the high frequency of heterozygous-like patterns may suggest that the reproductive system of O. latifolia might be more complex. Future research may explain the genetic patterns as well as the reproductive biology of this species. The knowledge of the genetic diversity and mating system of O. latifolia could contribute to the implementation of genetic resource conservation strategies and gene flow analyses, as well as of breeding programs for rice improvement.     

82 份水稻种质资源的稻瘟病抗性评价与抗性基因鉴定

为了合理利用水稻抗稻瘟病种质资源,通过稻瘟病菌株接种鉴定并结合9个主效抗性基因的特异性分子标记检测,分析了82份地方稻种资源的稻瘟病抗性水平和携带的抗性基因.结果表明:在82份水稻材料中,宽抗谱和中等抗谱的材料分别有11份(13.4％)和55份(67.1％).携带Pia、Pita-2/Pita、Pita、Piz、Piz-t和Pik-h基因的材料分别占78.0％、76.8％、54.9％、50.0％、39.0％和35.4％;各有3个材料携带Pik基因和Pib基因,未发现携带Pik-m基因的材料.大部分供试材料含有2～5个抗性基因,随着抗性基因数量的增加,供试材料的抗病性呈上升趋势.     

蝴蝶兰种质资源及杂交育种进展

蝴蝶兰的发现距今约190年,经过120多年来不断的杂交育种,取得了令人瞩目的成就,已登录了蝴蝶兰杂交种31 818个,极大地推动了蝴蝶兰产业的发展,使其成为全球重要的盆栽花卉之一.我国是蝴蝶兰的原产地之一,台湾地区早在20世纪80年代就树立了世界蝴蝶兰育种中心的地位.经过近30年的快速发展,我国大陆地区也成为全球重要的蝴蝶兰生产和消费地之一,但由于育种工作起步晚,品种仍主要依赖引进,自主培育的品种不多,与产业规模形成巨大反差.综述了国际蝴蝶兰种质资源的现状及其杂交育种进展,指出存在问题和不足,为开展蝴蝶兰育种提供了一些思路和方向.     

罗田甜柿种质资源ISSR分子标记初步鉴定

分别采集湖北省罗田县、麻城市自然分布的28、8株罗田甜柿(Diospyros kaki Thunb cv.Oriental persimmon)古树优系及小涩柿、无核、宝盖、秋焰甜柿优系为研究材料,利用简单重复序列间扩增分子标记(Inter simple sequence repeat,ISSR)技术对40个甜柿优系进行初步认证及亲缘关系分析。结果表明:1从21条ISSR引物中筛选出了9条能够扩增出清晰、稳定条带的引物,9条引物共扩增出185条谱带,其中多态性条带有185条,多态性条带比率为100%;2应用NTSYS2.10e软件对扩增结果进行非加权组平均法(Unweighted pair-group method with arithmetic means,UPGMA)聚类分析,40个甜柿优系大致被分为两大类,遗传相似系数从0.39到0.92;3罗田甜柿古树基因资源丰富,每个基因型都有其独特的指纹图谱,遗传多样性高。罗田甜柿优系间的亲缘关系与地理来源有一定的相关性,麻城市与罗田县地理位置交界区域的罗田甜柿资源相对集中在A区,其他地理位置采集优系集中在B区。分析结果可为罗田甜柿种质资源开发、基因资源保存、后期品种审定及鉴别提供理论依据。