基于Landsat 8数据的荒漠土壤水分遥感反演

[目的]分析荒漠土壤水分变化特征,为南疆干旱区荒漠土壤水分遥感监测提供理论依据和方法支持。[方法]以Landsat 8数据构建干旱地区荒漠土壤水分建模指示因子,通过优选的26个光谱指数、地表温度(Ts)和地形数据(DEM)为建模因子,分别以偏最小二乘(PLSR)、支持向量机(SVM)和随机森林(RF)3种方法构建土壤水分反演模型,对模型进行验证和对比,选取最优模型反演空台里克土壤水分空间分布。[结果]①TVDI,NR,GLI等26个优选的光谱指数中,Ts和DEM与土壤水分均达极显著相关,可作为南疆干旱区荒漠土壤水分遥感建模的指示因子;②对比3种模型,RF模型建模集和预测集的R²分别为0.93,0.91,预测集RPD为3.90,各评价指标均为最高,PLSR模型精度次之,SVM模型精度最低;③以RF模型反演研究区表层土壤水分,在不同土地利用分类中土壤水分分布特征存在明显差异,特别在盐结皮区域的差异尤为突出。[结论]利用光谱指数、环境因子和地形数据构建的多因子、多指数综合的模型能较高精度地反演干旱区荒漠表层土壤水分,对研究该地区土地荒漠化和生态环境治理具有一定参考价值。     

楸树叶片年龄与位置效应的生理指标变化研究

为探究楸树生长过程中生理指标的变化规律,选择古楸树无性繁殖材料,对不同年龄及部位的楸树叶片中超氧化物歧化酶（SOD）活性、过氧化物酶（POD）活性、可溶性糖含量、可溶性蛋白含量及叶绿素含量进行了测定。结果表明:1）叶绿素、可溶性蛋白及可溶性糖含量随楸树年龄增加呈现不断减少的趋势,SOD活性及POD活性随年龄增加不断上升。300年生冠部较3年生冠部叶绿素减少了23.89%,可溶性蛋白减少了72.81%,可溶性糖减少了58.71%,SOD活性增加了26.82%,POD活性增加了139.69% 。2）位置效应方面,根萌条叶片叶绿素、可溶性糖及POD活性低于冠部叶片,而SOD活性和可溶性蛋白则高于冠部。其中,叶绿素在300年生叶片根、冠部差异最大,冠部是根部的1.99倍;可溶性蛋白、可溶性糖含量和SOD活性均在3年生楸树叶片根、冠部差异最大,根部较冠部分别增加了12.11%、21.28%、28.51%。POD活性则在15年生处差异最大,冠部是根部的1.71倍。综上所述,300年生楸树叶片抗性较高,且具有明晰的遗传背景,是培育优良楸树较佳的无性繁殖材料。根部枝条相对于冠部枝条生理年龄较小,且300年生根部和冠部叶片可溶性蛋白和SOD含量没有显著差异,根部枝条是无性繁殖材料选择的较佳位置。     

Breeding progress for yield in winter wheat genotypes targeted to irrigated environments of the CWANA region

The international winter wheat improvement program (IWWIP), an alliance between Turkey–CIMMYT–ICARDA, has distributed improved germplasm to different National Agricultural Research Systems (NARS) partners through international nurseries and yield trials for the last 25 years. This study was carried out in order to determine the rate of breeding progress for yield and yield related traits at IWWIP using data of the international winter wheat yield trials (IWWYT), IWWYT 1–13, collected from 1997 to 2010 in irrigated environments across different countries. The relative grain yield of the best line expressed as percent of the best check (Kinaci-97), widely grown cultivar (Bezostaya) and trial mean (TM) increased at a rate of 0.6, 1.6 and 0.2 %/year, each non-significant (P > 0.05), respectively. Regression analysis indicated that TM has increased at a rate of 91.9 kg/ha/year (P = 0.007). The net realized breeding progress was estimated by accounting the variability due to management and weather conditions using surrogate variables such as integrated biological indices taken as means of common checks. The net realized gain for the BL was 66.2 ± 19.7 kg/ha/year (P = 0.01). Success rate of the BL, per cent of sites where the BL exceeds the local check in grain yield, ranged from 50 to 87 % across trials. To date, more than 55 varieties of IWWIP origin have been released in 10 countries of Central and West Asia including Afghanistan, Turkey, Iran, Uzbekistan and Tajikistan. Some varieties, such as Solh and Kinaci-97, have been released under different names in different countries indicating their broad adaptation. Cluster analysis of IWWYT sites indicated that IWWIP sites in Turkey and Syria are associated with most of the testing sites in Central and West Asia and North Africa (CWANA) region. The recently identified high yielding genotypes are recommended for direct release and/or parental purposes by the respective NARS.     

Dynamic analysis of an array of semi-rigid “sea station” fish cages subjected to waves

The dynamic behaviour of an array of 6 × 6 semi-rigid “sea station” fish cages is studied under the effect of waves. The semi-rigid sea station system is discretized into a lumped mass model, that is used as the dynamic simulation model. The tension in the mooring lines of the mooring system is obtained in the time domain for different wave directions. The rotations of three degrees of freedom of each semi-rigid sea station under different wave directions are analysed, and the spectral density function of the mooring tension is obtained by Fast Fourier Transform of the time domain response. The results provide a basis for the design of the semi-rigid sea station system and have a certain guiding significance for the specific engineering practice.     

叶面喷施外源多胺提高夏玉米灌浆前期抗涝性

为缓解玉米涝渍胁迫危害,该研究在夏玉米灌浆前期设置3、5、7、9 d的测坑淹水试验,分析淹水及淹水后叶面喷施外源多胺对夏玉米叶片可溶性糖、根系活力、地上部干物质、内源亚精胺、籽粒质量动态变化和产量的影响。结果表明:淹水后与CK相比,淹水5、7、9 d叶片可溶性糖含量下降,地上部干物质质量均显著减少,淹水3、7、9 d百粒质量增加,5 d减少,籽粒质量、穗行数、行粒数、产量均显著降低。叶面喷施外源多胺后,相同淹水天数处理间比较,淹水5、7、9 d叶片可溶性糖含量增加、根系活力增强,淹水7、9 d叶片内源亚精胺含量增加,淹水5 d百粒质量显著增加,淹水3、5 d植株行粒数分别增加8.24%和7.41%,产量分别提高7.92%、5.85%(P0.05)。因此,夏玉米灌浆前期遭遇淹水后5 d内叶面喷施外源多胺,能够提高其抗涝性,减少产量损失。     

我国渔业船舶技术法规体系的研究

通过梳理我国渔业船舶技术法规体系的发展现状,发现我国渔业船舶法规技术体系存在三大问题。一是渔业船舶技术法规体系不健全,现有法规与渔业发展实际状况偏差较大。二是渔业行政管理体系与技术条款执行关系模糊。三是渔业船舶技术研究技术力量薄弱。研究表明:(1)应完善顶层设计,在渔船检验领域逐步引入市场竞争机制,形成政府主导、市场调节的渔船检验体制;(2)应通过技术创新和引进吸纳技术创新,提高指标参数的先进性和国际化水准;(3)应创新管理和组织制度,规范采标、制标流程,避免盲目采标和制标;(4)政府应加大政策与法规等制度的研究性投入,为技术标准和法规体系建设储备知识要素,为体系建设提供可靠的智力支撑。     

Identification of genetic loci in a rhizosphere-inhabiting,species of Pseudomonas involved in expression of a phytoparasitic nematode ovicidal factor

Pseudomonas sp. BG33R was isolated from peach orchard soil suppressive to the phytoparasitic ring nematode, Mesocriconema xenoplax. Tn5 transposon mutagenesis was utilized to generate five BG33R mutants 246, 1122, 1233, 1397, and 1917, which lacked ovicidal activity and also exhibited altered fluorescent siderophore and protease production. Southern blot analysis revealed that each of the five mutants contained a single unique Tn5 insertion. Mobilization of selected BG33R genomic cosmid clones into mutants 246 and 1917 restored egg-kill activity and restored normal protease and siderophore production. Furthermore, a genomic cosmid clone hybridizing to the Tn5 insertion site in 1122 also complemented mutant 1917. Site-directed mutagenesis of BG33R using the cloned Tn5 insertion site from mutant 1397 resulted in the loss of ovicidal activity and restoration of the hyperfluorescence phenotype. Sequence analysis was performed on the genetic regions flanking the Tn5 insertion site in all five egg-kill-negative mutants. Open reading frame analysis and amino acid comparative database searches of the Tn5 insertion sites in the five mutants revealed a high degree of homology to the vgrG gene, the two-component sensor kinase protein, rtpA (gacS analog), a UDP-glucose 4-epimerase gene, a siderophore receptor protein, and the 50S ribosomal protein, L21. The involvement of these genes in the production of the egg-kill factor is discussed.     

IGF-1R,p-ERK is involved in LDLs-induced mouse peritoneal macrophage survival

AIM: To study the effects of low density lipoproteins (LDLs) on insulin-like growth factor-1 receptor (IGF-1R), phosphorylated extracellular signal-regulated kinase (p-ERK), Bcl-2 and Bax protein expression in mouse peritoneal macrophages (MPMs). METHODS: Using the methods of immunocytochemistry and Western blotting, the expression of IGF-1R, p-ERK, Bcl-2 and Bax protein in MPMs treated with LDLs, anti-IGF-1R antibody (α-IR-3) or ERK inhibitor (PD98059) were detected. RESULTS: oxLDL significantly increased the IGF-1R protein expression in a dose and time-dependent manner. P-ERK protein expression induced by oxLDL peaked at 5 min. Moreover, oxLDL could induced ERK translocation from cytoplasm to nuclear. When given α-IR-3, p-ERK protein expression was significantly inhibited, and ERK translocation disappeared. oxLDL increased Bcl-2 protein expression and reduced Bax expression in a dose and time-dependent manner. When given PD98059, Bcl-2 and Bax protein expression induced by oxLDL altered significantly. Native LDL had no significant effect on the expression of these four proteins. CONCLUSIONS: oxLDL may promote cultured MPMs survival at least by enhancing IGF-1R expression and ERK phosphorylation, and there may be many pathways involved in MPMs survival induced by oxLDL, Whereas native LDL had no effects on culture MPMs.     

中国黄土滑坡灾害概述

中国的黄土面积约占国土总面积的6.63%,是世界上黄土分布最广的国家。由于自然条件的限制,滑坡灾害频繁发生,已成为黄土地区社会经济发展的主要障碍。本文通过不同分类指标,把黄土地区滑坡概化为9种类型,并重点分析黄土地区滑坡灾害的时空分布特点以及黄土地区滑坡的影响因子即滑坡机理。指出黄土地区的滑坡在空间分布上与地质构造、地形地貌、地震发育情况、降水密切相关;从地形地貌、地层岩性、新构造运动和地震活动情况、水的影响以及人类活动不同方面对黄土地区滑坡的发生机理进行了分析,发现黄土地区存在易发生滑坡的先天自然条件,而人类活动又加速了滑坡的发生。本文指出控制黄土地区滑坡灾害,寻找最佳防治对策是当前的紧迫任务。表1参14。     

放牧和刈割对坝上草原羊草根茎与营养枝生长的影响

在河北张家口坝上羊苹草原上,选择植被均匀、微地形差异较小的割草地和放牧地作为研究样地,通过对羊草种群的营养枝和根茎两个指标研究表明：割草地与放牧营养枝和根茎呈不显著拮抗关系,放牧地根茎随季节波动性要显著大于割草地。综合分析结果表明,割草地羊草种群的营养枝和根茎生物性状要优于放牧地。