基于STIRPAT模型的昌吉市建设用地空间布局及社会经济驱动力分析

随着城乡建设用地空间扩展与土地资源局限性矛盾的日益突出,开展城乡建设用地布局优化研究显得极为重要。针对新疆昌吉市建设用地扩展现状,利用建设用地审批矢量数据,运用GIS统计分析功能和空间分析功能,对昌吉市建设用地扩展数量特点及空间分布特征进行分析,并在此基础上利用STIRPAT模型对建设用地扩展的社会经济驱动因子进行定量分析。结果表明,(1)昌吉市建设用地扩展速度与强度在2010-2011年呈现增加趋势,2011-2015年呈现下降趋势;(2)建设用地扩展的空间分析得出,四、五、六及十方向扇区建设用地发展指向性较突出,表明建设用地发展空间布局的区域指向性特征较明显;(3)国内生产总值是建设用地扩展的最主要驱动因子,全社会固定资产投资、城镇人均可支配收入、农牧民人均纯收入、第二产业贡献率与建设用地的扩展也有明显的相关性。研究表明,采用等扇分析方法与STIRPAT评价模型可以清晰刻画出不同扇区建设用地变化规律及其与各驱动因子间相互契合程度,对未来较好地实现土地资源集约优化利用和经济可持续发展有一定的指导意义。     

甜橙和柚中CTV强弱毒株系p20的遗传变异

【目的】对7个柑橘衰退病毒(CTV)株系进行遗传变异研究,明确寄主甜橙和柚中CTV强弱毒株系p20的变异水平。【方法】运用RT-PCR、克隆及测序等技术建立CTV p20种群,并借助MEGA6构建单倍型系统发育树,运用软件DNAStar对两种寄主中CTV强弱毒种群的遗传结构、变异水平进行分析,运用DnaSP软件对各种群进行单倍型多样性、核苷酸多样性分析和中性检验分析。【结果】构建了7个CTV p20种群,由162条序列构成,包含11个单倍型,单个种群有1个或更多单倍型出现。序列分析发现,来自不同种群的单倍型对应的原始核苷酸序列一致性为88.2%—100.0%,对应的氨基酸序列的一致性为92.3%—100.0%,最低的氨基酸序列一致性发生在CT23-1和CT9-2之间;其中单倍型PeraIAC-4、CT22和CT9-1共有50条序列,对应的原始核苷酸序列一致性为100.0%,属优势单倍型,与标准株系T36亲缘关系较近;单倍型多样性最丰富的是甜橙种群PeraIAC,单倍型多样性为0.800,而单倍型多样性最低的是柚种群CT22,单倍型多样性为0.170;相比柚种群的单倍型多样性(0.170—0.552)和核苷酸多样性(0.00032—0.05919),甜橙种群具有更为丰富的单倍型多样性(0.513—0.800)和核苷酸多样性(0.04208—0.05677)。系统发育树分析表明,来自甜橙的分离株种群结构复杂,甜橙种群中检测到的单倍型与标准株系T30、T36、VT和T3均有相关性;与标准株系T3相距很近的CT31-2与优势单倍型在系统发育树上距离最远,对应的原始核苷酸序列一致性仅为88.3%。中性检验结果表明,CTV甜橙种群趋于平衡或收缩状态,而CTV柚种群除CT23外则趋于扩张状态;其中TR-514Y、CT31和CT23种群的Tajima’s D值、Fu和Li’s D*值以及Fu和Li’s F*值均为正值且达到显著水平,而CT9种群的Tajima’s D值、Fu和Li’s D*值以及Fu和Li’s F*值均为负值且达到显著水平。运用DnaSP软件对各种群进行重组分析表明,在各种群中均未检测到重组事件发生。种群变异分析发现,各种群突变克隆百分比在0—30.8%,碱基突变频率在0—7.706×10~(-4),其中CTV甜橙强毒种群有最高的突变克隆百分比(30.8%),最高的碱基突变频率(7.706×10~(-4)),最多的碱基突变数量(11个)和最多的突变位点(7个);CTV甜橙弱毒种群的突变克隆百分比和碱基突变频率均明显低于甜橙强毒种群,CTV柚弱毒种群的突变克隆百分比和碱基突变频率略低于柚强毒种群。碱基突变类型分析发现碱基突变以碱基替代为主,其中A→G突变为优势类型,仅在柚强毒种群CT3的156和157位点间检测到一个碱基插入突变类型,为碱基A插入,未检测到碱基缺失突变类型。【结论】在寄主甜橙和柚中CTV强弱毒p20种群结构及变异存在差异,CTV甜橙种群有着更复杂的种群结构和更高的种群变异水平,且CTV强毒种群变异更大。     

Turnover of Village Chickens Undermines Vaccine Coverage to Control HPAI H5N1

Highly pathogenic avian influenza (HPAI) subtype H5N1 remains an enzootic disease of village chickens in Indonesia, posing ongoing risk at the animal–human interface. Previous modelling showed that the fast natural turnover of chicken populations might undermine herd immunity after vaccination, although actual details of how this effect applies to Indonesia's village chicken population have not been determined. We explored the turnover effect in Indonesia's scavenging and mixed populations of village chickens using an extended Leslie matrix model parameterized with data collected from village chicken flocks in Java region, Indonesia. Population dynamics were simulated for 208 weeks; the turnover effect was simulated for 16 weeks after vaccination in two ‘best case’ scenarios, where the whole population (scenario 1), or birds aged over 14 days (scenario 2), were vaccinated. We found that the scavenging and mixed populations have different productive traits. When steady‐state dynamics are reached, both populations are dominated by females (54.5%), and ‘growers’ and ‘chicks’ represent the most abundant age stages with 39% and 38% in the scavenging, and 60% and 25% in the mixed population, respectively. Simulations showed that the population turnover might reduce the herd immunity below the critical threshold that prevents the re‐emergence of HPAI H5N1 4–8 weeks (scavenging) and 6–9 weeks (mixed population) after vaccination in scenario 1, and 2–6 weeks (scavenging) and 4–7 weeks (mixed population) after vaccination in scenario 2. In conclusion, we found that Indonesia's village chicken population does not have a unique underlying population dynamic and therefore, different turnover effects on herd immunity may be expected after vaccination; nonetheless, our simulations carried out in best case scenarios highlight the limitations of current vaccine technologies to control HPAI H5N1. This suggests that the improvements and complementary strategies are necessary and must be explored.     

Conservation priorities for the different lines of Dutch Red and White Friesian cattle change when relationships with other breeds are taken into account

From a genetic point of view, the selection of breeds and animals within breeds for conservation in a national gene pool can be based on a maximum diversity strategy. This implies that priority is given to conservation of breeds and animals that diverge most and overlap of conserved diversity is minimized. This study investigated the genetic diversity in the Dutch Red and White Friesian (DFR) cattle breed and its contribution to the total genetic diversity in the pool of the Dutch dairy breeds. All Dutch cattle breeds are clearly distinct, except for Dutch Friesian breed (DF) and DFR and have their own specific genetic identity. DFR has a small but unique contribution to the total genetic diversity of Dutch cattle breeds and is closely related to the Dutch Friesian breed. Seven different lines are distinguished within the DFR breed and all contribute to the diversity of the DFR breed. Two lines show the largest contributions to the genetic diversity in DFR. One of these lines comprises unique diversity both within the breed and across all cattle breeds. The other line comprises unique diversity for the DFR but overlaps with the Holstein Friesian breed. There seems to be no necessity to conserve the other five lines separately, because their level of differentiation is very low. This study illustrates that, when taking conservation decisions for a breed, it is worthwhile to take into account the population structure of the breed itself and the relationships with other breeds.     

群体密度与黄腐酸对芸豆籽粒淀粉形成及加工特性的影响

为探明群体密度与叶面喷施黄腐酸对黑龙江省西北部芸豆籽粒淀粉形成及加工特性的影响,采用二因素裂区设计,主区设3个群体密度：20万株·hm^-2(D1,稀植处理)、23万株·hm^-2(D2,当地常规密度)、26万株·hm^-2(D3,密植处理);副区设5个黄腐酸浓度：清水(C0)、0.37(C1)、0.45(C2)、1.12(C3)、1.50 kg·hm^-2(C4)。采用碱液浸提法提取成熟后芸豆籽粒淀粉,通过测定淀粉的溶解度、膨胀度、冻融稳定性、糊化特性、透明度、直链淀粉含量以及淀粉的理化性质,研究了芸豆淀粉品质形成的群体效应及叶面肥调控效果。结果表明：芸豆籽粒粗淀粉含量及直链淀粉比例显著影响淀粉的加工特性。2021年、2022年芸豆淀粉含量均随群体密度的增加而增加,分别从45.7%、47.7%增加到59.0%、50.7%;同时,直链淀粉含量均在高密度(26万株·hm^-2)处理下达到峰值,分别为36.3%和28.4%。叶面喷施黄腐酸促进了芸豆籽粒淀粉的积累,提高了籽粒总淀粉含量,增加了...     

雷州半岛徐闻红树林植物群落的结构和动态特征

为揭示不同潮位红树林群落结构及动态规律,本文对雷州半岛徐闻官曹红树林群落的物种组成、物种年龄结构和多样性等群落特征进行了分析.结果表明:离岸高潮位和和中潮位均为白骨壤+红海榄群落,低潮位为白骨壤群落,反映随潮位的降低,群落物种数逐渐减少,白骨壤种群在各潮位均为优势种,具较宽生态位,而次优势种群红海榄则只分布于中高潮位,生态位相对较窄.白骨壤和红海榄在所出现的潮位中,其幼苗和苗木均较多,年龄结构均属于增长型.各群落物种多样性Simpson指数(D)、Shannon(H)和Pielou均匀度指数(J)的大小顺序关系均为中潮位的白骨壤+红海榄群落＞高潮位的白骨壤+红海榄＞低潮位的白骨壤群落.隐含着高潮位物种竞争剧烈,均匀度较小,中潮位物种关系稳定,均匀度较大,低潮位物种受环境严重胁迫表现适生选择性.白骨壤和红海榄在所出现的潮位中,种群格局均属于集群分布,反映其典型的胎生红树特征.     

Genetic diversity of pine‐parasitic nematodes Bursaphelenchus xylophilus and Bursaphelenchus mucronatus in China

The internal transcribed spacer (ITS) regions of rDNA have been routinely employed for identification and phylogenetic analysis of many nematode species. In this study, the intra‐ and interspecies ITS genetic diversity of Bursaphelenchus xylophilus and Bursaphelenchus mucronatus was evaluated. Ninety‐one isolates of the two nematode species collected from 14 Chinese provinces, Japan and Korea were used for ITS‐PCR and sequencing. An unweighted pair group cluster analysis dendrogram clustered them as two B. mucronatus and one B. xylophilus independent clades. Principal component analysis showed the phylogenetic relationship of the two nematode species more clearly; B. mucronatus isolates were separated into more than four groups, whereas B. xylophilus isolates still clustered into a group. The results of the Mantel test indicated the correlation of genetic distance matrices and geographic distance matrices was significant for both nematode species. The genetic differentiation coefficient (G_st) and gene flow (N_m) of B. mucronatus were 0.341 and 1.091, respectively, suggesting the importance of landscape heterogeneity and considerable obstacles for genetic exchange among B. mucronatus isolates in China. However, G_st and N_m of B. xylophilus were 0.188 and 2.151, respectively, very different compared to B. mucronatus. This could be owing to the short‐term introduction of B. xylophilus into China and a rapid spread through anthropogenic pathways. Our work adds to the understanding of the genetic diversity and genetic relationship of the two pine‐parasitic nematode species, and will aid in controlling them in the future.     

盐胁迫对南方泡桐基因表达的影响

为阐明泡桐多倍体的耐盐分子机制,以南方泡桐二倍体及对应的四倍体为试验材料,以白花泡桐基因组为参考序列,利用RNA-Seq测序技术,研究了盐处理前后南方泡桐四倍体和对应二倍体的基因表达变化。通过比对分析,共鉴定出与盐胁迫相关的差异表达基因2 940个。对这些差异基因进行GO功能分类,结果显示差异基因共参与了39个分类,集中在细胞、结合、催化等分类功能区的数量最多。KEGG代谢通路分析发现,这些差异表达基因主要参与了Plant hormone signal transduction,Carbon metabolism,Biosynthesis of amino acid等,其中编码MYB、WRKY、bZIP、ATPase等的基因差异表达显著。表明这些基因可能是潜在的盐胁迫响应基因。采用qRTPCR技术验证了随机挑选的9个差异表达基因,结果与转录组测序数据趋势一致。     

基于玉米DH育种技术的“吉农玉833”选育报告

按照Reid、Non-Reid、Dom及其构成的三角型杂种优势模式,构建基础群体,采用DH育种技术于2015年育成玉米新品种"吉农玉833"。该品种在吉林省2013—2014年区域试验中平均产量13 724.0 kg/hm~2,比对照品种"郑单958"增产10.5%。2014年生产试验平均产量12 278.0 kg/hm~2,比对照品种"郑单958"增产8.1%。2015年3月通过吉林省农作物品种审定委员会审定。该品种的育成进一步证明了适于当地的杂种优势模式理论原则,以及DH育种技术的成熟。     

危害贵州黑麦草与豆禾混播人工草地的叶蝉种类及发生动态

为探明危害贵州黑麦草人工草地和混播草地的叶蝉种类及发生动态,为该类害虫的防治提供参考,采用网捕法调查2种草地的叶蝉种类和发生动态。结果表明:危害黑麦草人工草地和豆禾混播草地的叶蝉种类主要有7种,分别是黑尾叶蝉[Nephotettix cincticeps(Uhler,1896)]、棉奥小叶蝉[Austroasca vittata(Lethierry,1884)]、烟草嘎叶蝉[Alobaldia tobae(Matsumura,1902)]、印度顶带叶蝉[Exitianus indicus(Distant,1908)]、二点叶蝉[Macrosteles fascifrons(Stl,1858)]、橙带铲头叶蝉[Hecalus porrectus(Walker,1858)]和异长柄叶蝉[Alebroides discretus ChouZhang,1987];危害豆禾混播草地的叶蝉主要是除印度顶带叶蝉外的其他6种。其中,棉奥小叶蝉和烟草嘎叶蝉为优势种群;棉奥小叶蝉种群数量在黑麦草草地呈双高峰型(分别在7月2日和8月15日),在混播草地上发生较轻;烟草嘎叶蝉在黑麦草草地上发生较轻,在7月中旬有1个发生高峰,在混播草地上则呈多峰型(集中于7月中旬至8月底)。