防治黄河下游粗泥沙淤积的新思路

黄河下游河床的淤积早已引起了有关部门和专家的关注,提出并采取了许多防治方案。但是,黄河下游的淤积并没有得到有效的控制。为此,笔者在前人工作的基础上,提出了一些新的防治思路。     

Isolation and characterization of resistance gene analogs (RGAs) from sorghum (Sorghum bicolor L. Moench)

Degenerate primers designed based on known resistant genes (R-genes) and resistance gene analogs (RGAs) were used in combinations to elucidate RGAs from Sorghum bicolor, cultivar M 35-1. Most of the previously tried primer combinations resulted in amplicons of expected 500–600 bp sizes in sorghum along with few novel combinations. Restriction analysis of PCR amplicons of expected size revealed a group of fragments present in a single band indicating the heterogeneous nature of the amplicon. Many of these were cloned and some were considered for analysis. The nucleotide sequence of different cloned fragments was done and their predicted amino acid sequences compared to each other and to the amino acid sequences of known R-genes revealed significant sequence similarity. A cluster analysis based on neighbor-joining (N-J) method was carried out using sorghum RGAs (SRGAs) together with several analogous known R-genes resulting in two major groups; cluster-I comprising only SRGAs and cluster-II comprised of known R-gene sequences along with three SRGAs. Further analysis clearly indicated similarity of SRGAs in overall sense with already known ones from other crop plants. These sequences can be used as guidelines to detect, map and eventually isolate numerous R-genes in sorghum.     

山西杂粮产业集群式发展的思考

农业产业集群具有抱团发展的优势,推进山西杂粮产业集群式发展是促进贫困地区经济发展、农民依靠产业脱贫的有效途径.文章基于产业集群视角对振兴山西杂粮产业进行分析、总结,系统探讨山西杂粮产业集群式发展的现实意义、基础条件、发展机遇、存在的短板,最后提出推进山西杂粮产业集群式发展的战略路径.山西杂粮的优品质、多品种、多功能为山...     

Stand development of Norway spruce dominated subalpine forests of the Swiss Alps

In densely populated regions, forests can help protect communities and infrastructures from natural hazards such as avalanches and rockfall. To promote the protective function, substantial efforts are made to actively manage forest stands. In 2009 alone the Swiss government invested more than 60 million sfr for the maintenance of protection forests. However, to date there has been no comprehensive evaluation of how the structural development of actively managed stands differs from that of passively managed stands in the Alps. Over the past century the structure of Norway-spruce dominated subalpine forests of the Swiss Alps has been changing and it is not clear how these changes affect the potential protective function of these forests, as well as other forest functions such as wildlife habitat. Furthermore, it is not clear how stand dynamics and structural changes differ between stands that are actively managed and those that are passively managed, and thus to what degree active efforts of forest management are contributing to stands that actually have a greater protective function than passively managed forests.In this study, we analyzed the dynamics of subalpine forests using time series of forest inventory data and examined the influence of active vs. passive management, exposition, distance to treeline, elevation and slope steepness on stand structure and dynamics. We analyzed data from 395 plots in dense, subalpine, spruce-dominated forests in the Swiss Alps. Data were collected during three distinct periods (1983-1985, 1993-1995 and 2004-2006) as part of the Swiss National Forest Inventory (NFI). Using regression trees and multivariate statistics, we investigated which factors have the most important influence on tree growth and stand development.Overall, forest density increased significantly over the last 20 years and the predominance of dense forests increased at higher elevations. However, forest density has not increased in actively managed forests over the past 10 years. In passively managed stands, density was higher on south-facing slopes than on north-facing slopes. The volume and density of dead wood has increased over the last 20 years in both actively managed and passively managed forests. Active management over the last 20 years has maintained forest conditions that adequately maintain stands’ protection functions in the Swiss Alps. However, stand development, especially increasing density, in the passively managed stands of the Swiss Alps suggests that the majority of passively managed stands also provide adequate protective functions against rock and avalanche hazards without the high costs of active management.     

The effects of windthrow on forest insect communities: a literature review

This paper reviews the effects that windstorm-induced drastic changes (micro-climate, soil, vegetation, and ground structural heterogeneity) have on forest insect communities. In the current context of shady and CWD-deprived managed forests, windthrow gaps act as regional biodiversity hotspots by maintaining habitat continuity in a mosaic landscape, and by facilitating the breeding and population growth of clearing specialists and saproxylic species. Windthrow gaps are dead-wood islands where forest protection and habitat conservation goals may stand against each other. Besides the quantitative effect of dead wood on bark beetle outbreaks and saproxylic diversity, the latter is favoured by key dead-wood micro-habitats such as large logs, snags and sun-exposed coarse woody debris. The role of natural enemies and sanitation operations in regulating pest outbreaks is discussed. Heterogeneous openings provide many micro-habitats favouring flower-visiting insects, phytophages on saplings, on fallen tree crowns, and on diverse understory flora, as well as ground insects on specific micro-sites.     

利用粗老原料加工速溶红茶的品质改进

利用粗老原料加工速红茶可降低成本，充分利用茶叶资源，然而，其品质普遍存在茶叶香味淡薄、风味不显等缺陷。本文就红茶风味形成的物质基础，加工过程的物质转换，粗老原料的成分状况进行了讨论，并针对上述品质问题提出了一些具体的方法和思路，涉及风味成分的添加1乌龙茶原料和工艺的引入等。     

黄河流域多沙粗沙区坝地防洪保收研究

淤地坝防洪能力包含两个方面,一是工程自身的防洪能力(即防御标准);二是坝地生产的防洪能力(即指坝地的防洪保收标准).淤地坝工程自身的防御标准,在有关规范中已有过明确规定和要求.而坝地生产的保收能力、保收标准,则是随着大规模坝地的形成和生产利用逐渐提出来的.从坝地淹水深度与淹水历时及淤积厚度对作物产量的影响考虑,提出了多沙粗沙区淤地坝防洪保收的标准为:洪水频率5%、作物保收率80%以上.通过淤地坝防洪保收指标和临界值的分析计算,得到黄河中游多沙粗沙区淤地坝防洪保收条件:坝地淹水深度小于作物株高的1/3,淹水历时在7天之内,淤泥厚小于作物株高的1/5.     

大肠杆菌K-12中PFL家族基因的生物信息学分析

从生物信息学角度，利用生物学数据库(GenBank、Swiss-Prot、PDB)和分子生物学分析软件Vector NTI8．0，对大肠杆菌K—12中的多个丙酮酸甲酸裂解酶(pyruvate formate-lyase，PFL)进行序列的比较分析和结构预测，进而分析其活性位点、相关保守位点和特殊结构域及序列的二级结构，为利用理性设计改造丙酮酸甲酸裂解酶提供一定的信息。