青海高寒山区种植密度对青麦10号春小麦群体性状及产量的影响*

目的：经过1-2年的试验,掌握春小麦新品种青麦10号在青海春麦主产区适宜的种植密度。方法：利用方差分析和相关分析获得种植密度对青麦10号的产量及产量构成因素影响的关系。结论：种植密度对青麦10号各农艺性状的影响差异显著,综合各群体性状指标,中密度处理可获得较好产量,本研究为青麦10号的推广提供理论依据。     

麦秆还田对直播和移栽棉花产量及氮素吸收的影响

为明确长江流域棉区植棉对麦秆还田的响应及其对麦秆中氮素的吸收利用效果,采用田间试验,设置棉花直播冬小麦秸秆不还田（D-S）、棉花直播冬小麦秸秆还田（D+S）、棉花移栽冬小麦秸秆不还田（P-S）和棉花移栽冬小麦秸秆还田（P+S）4个处理。利用¹⁵N同位素示踪技术研究麦秆还田对直播和移栽棉花的产量、生物量、氮素吸收及秸秆氮利用率的影响。结果显示,麦秆还田可不同程度地增加直播和移栽棉花的产量、秸秆生物量和根系生物量。直播条件下,麦秆还田后棉花籽棉产量、叶片、茎秆、棉壳和根系生物量的增幅分别为7.8%、3.7%、4.6%、3.4%和14.6%;移栽条件下,麦秆还田后棉花产量及各部位生物量的增幅分别为5.9%、5.2%、5.6%、7.4%和7.9%。从棉花生物量和产量来看,各处理均表现为P+S>P-S>D+S>D-S。收获期,与麦秆不还田相比,麦秆还田后直播和移栽棉花的根系数、果枝数、叶片数、叶片SPAD、单株铃数和单铃重均有明显增加,而株高、根茎粗和衣分的差异并不显著。与D-S处理相比,D+S、P-S和P+S处理的棉株氮素吸收量分别增加14.4、34.6和51.1 kg·hm^-2,增幅达到9.0%、21.8%和32.2%。表观法和¹⁵N示踪法得出棉花季麦秆氮素的平均回收率分别为22.3%和11.5%,且移栽棉花对麦秆氮素的利用率高于直播棉花,表明棉花季大部分小麦秸秆氮素残留在土壤中。因此,在长江流域麦-棉轮作区,积极开展麦秆还田技术可增加直播、移栽棉花的产量和棉株氮素吸收,并减少化学氮肥施用,从而提高秸秆氮素养分的循环利用效率。研究可为作物秸秆资源利用和棉花季氮肥科学减量施用提供参考依据。     

种植密度对转Bt棉纤维杀虫蛋白表达量及氮代谢的影响

为了探讨种植密度对转基因抗虫棉纤维中杀虫(Bt)蛋白表达量的影响及其氮代谢机制,以Bt棉常规种泗抗1号和Bt棉杂交种泗抗3号为试验材料,比较1.5×10⁴、3.0×10⁴、4.5×10⁴、6.0×10⁴、7.5×10⁴ 株·hm^-2五个种植密度下转Bt棉杀虫蛋白表达量及其氮代谢的差异。结果表明,纤维中Bt蛋白表达量随种植密度增大呈上升趋势。相关分析表明,单株铃数、单铃体积、单铃干重与Bt蛋白表达量均呈显著负相关。纤维中氮代谢生理相关指标中,可溶性蛋白含量及谷氨酸丙酮酸转氨酶(GPT)和谷氨酸草酰乙酸转氨酶(GOT)活性随种植密度的增大而升高,但游离氨基酸含量、蛋白酶和肽酶活性随密度增大而下降。纤维中Bt蛋白表达量与可溶性蛋白含量、GPT和GOT活性呈显著正相关,而与游离氨基酸含量、蛋白酶和肽酶活性呈显著负相关。可见,提高种植密度降低了棉铃生长,但提高了纤维中Bt蛋白的表达量,且Bt蛋白表达量的提高与植株氮代谢生理密切相关。因此,在生产中通过协调种植密度既可以保持棉铃适度发育,又有利于提高棉纤维中Bt蛋白的表达量,为提高Bt棉产量器官抗虫性提供栽培基础。     

种植密度对南疆机采棉群体农艺特征和产量的影响

在新疆南疆地区自然生态条件下,以中棉所88号为试验材料,采用单因素随机区组试验设计,设置6个种植密度（P1：9万株·hm^-2,P2：12万株·hm^-2,P3：15万株·hm^-2,P4：18万株·hm^-2、P5：21万株·hm^-2,P6：24万株·hm^-2）,研究了一膜六行机采棉模式下棉花株高、主茎日增长量、茎粗、节枝比、叶面积指数（leaf area index,LAI）、冠层开度、叶倾角和产量对种植密度的响应。结果表明：增大密度显著降低了棉花的株高、茎粗、单株叶面积、冠层开度及节枝比（P<0.05）;主茎日增量在初花期以前为密度越大其越高,初花期后则反之;各处理LAI均在盛铃前期达到峰值,以P4处理最高为4.74;叶倾角则随密度增大而增大,各处理在30.0°～46.9°浮动;籽棉及皮棉产量均在P5处理达到最高,分别为6 272.79 kg·hm^-2和2 874.82 kg·hm-²但其与P3、P4处理均无显著差异。综上得出,在一膜六行机采模式下,南疆棉花的种植密度在15万～18万株·hm^-2范围内,棉花株型及冠层结构良好,产量较高。     

东海浮游异足类环境适应分析

根据1997~2000年东海23°30′~33°00′N、118°30′~128°00′E海域4个季节海洋调查资料,采用浮游异足类物种丰度和同步的温、盐度数据拟合曲线,构建数学模型,计算物种分布的最适温度和盐度值。同时根据以往对异足类生态特征分析的结论,划分东海浮游异足类各物种的生态类型。结果表明,塔明螺(Atlanta turriculata)和拟翼管螺(Firoloi-da desmaresti)分布在外海,具有高温、高盐的适应特征,是热带大洋种。其他为亚热带外海种,其中玫瑰明螺(Atlantarosea)具广温种特征,明螺(Atlanta peroni)适温偏低,有广盐种的特征,大口明螺(Atlanta lesueuri)分布在盐度较高的水域,扁明螺(Atlanta depressa)具有近海种特征。东海浮游异足类总体上属于典型的暖水性生态类型,温、盐适应范围较窄,对水温和盐度敏感,是较好的指示种。东海浮游异足类主要分布在28°00′~30°00′N,124°00′~126°00′E的海域,绝大多数物种难以逾越冷水水团的阻隔,这是浮游异足类很少在黄渤海出现的主要原因之一。浮游异足类生态类型划分在古气象海洋学、海洋地质、海洋物理和海洋生物学的研究中具有重要的意义。     

高邮湖鱼类群落结构特征

为了解高邮湖鱼类群落结构特征,采用三层刺网和单目地笼网鱼类采样工具,于2019-2020年在该湖泊设置的5个点位进行4次调查,鉴定了渔获物种类,分析了鱼类生态类型和群落结构特征指数。结果显示:高邮湖鱼类24种,隶属20属7科6目。淡水性、肉食性和中上层鱼类为优势生态型。鲫(Carassius auratus)、大银鱼(Protosalanx hyalocranius)、鳙(Hypophthalmichthys nobilis)、黄颡鱼(Pelteobagrus fulvidraco)、刀鲚(Coilia nasus)和鲢(H.molitrix)为高邮湖优势种。平均Shannon-Wiener多样性指数为1.45,Pielou均匀度指数为0.61,Simpson优势度指数为0.6,Margalef种类丰富度指数为1.91。与历史资料相比,鱼类群落多样性和丰富度指数有所提高,但群落结构受干扰程度较高。Cluster聚类和nMDS平面图显示,高邮湖不同空间的鱼类多样性差异较小;而与其北部入湖口河流水域相比,鱼类群落结构差异显著。过水性高邮湖的鱼类多样性高于河道,但总体上鱼类物种多样性处于较低水平。     

Predicting summer fin whale distribution in the Pelagos Sanctuary (north-western Mediterranean Sea) to identify dynamic whale–vessel collision risk areas

1. Mediterranean fin whales aggregating in the Pelagos Sanctuary in summer to feed are exposed to vessel collision risk, particularly from high-speed ferries.
2. This study developed models to predict summer fin whale distribution using a generalized additive model (GAM) and MaxEnt, with the aim of providing a tool to identify potential high whale–ferry collision risk areas along ferry routes within the Pelagos Sanctuary during summertime.
3. Models were trained using sightings data collected in the summer months of 2009–2018 on board ferries crossing the central area of the Pelagos Sanctuary. Environmental predictors were bathymetry and mean sea surface chlorophyll concentration of the annual spring bloom period.
4. The predictive ability of GAM and MaxEnt was assessed using existing knowledge of summer fin whale distribution in the region. GAM (deviance explained = 20.2%) predictions matched documented distributions more closely than that of MaxEnt, with highest predicted fin whale occurrence in deep offshore waters (>2000 m) encompassing the central north-western and western regions, and in the south-eastern region, consistent with known fin whale habitats within the Pelagos Sanctuary. Inter-annual variability was evident, influencing collision risk areas.
5. Collision risk was estimated as a function of the overlap between the predicted probability of fin whale occurrence and ferry density estimated from Automated Identification System data. Ferry routes that cross the northern and eastern regions of the Pelagos Sanctuary presented relatively higher collision risk.
6. Areas with changes in risk intensity between the years were temporally and spatially dynamic: some appeared intermittently throughout the study period while others persisted over consecutive years or recurred in different years.
7. Due to the vastness of the Pelagos Sanctuary, vessel speed reduction maybe a more practical measure to manage collision risk than re-routing shipping lanes. A combination of Seasonal Management Areas and Dynamic Management Areas approaches could be adopted for high-risk areas.

     

珠母贝属6个种的ITS 2分子标记研究

对珠母贝属的大珠母贝、珠母贝、白珠母贝、黑珠母贝、长耳珠母贝、黑珠母贝和合浦珠母贝6个种的内部转录间隔区2(ITS2)序列及其两侧的5.8S和28S的部分序列进行了比较分析。其中黑珠母贝的序列来自GenBank。PCR扩增片段大小为600bp左右,测序结果表明,ITS2长211～254bp,两端的5.8S和28S分别长84bp和272bp(均含引物)。序列比对分析结果表明,5.8S和28S序列高度保守,不适合于种类鉴定,而ITS2序列高度变异,270个比对位点中有146个位点发生突变,其中72个位点发生插入/缺失突变。除白珠母贝和黑珠母贝之间的遗传距离较小外,其余种类之间的遗传距离远远大于种内遗传距离。基因型分析表明,每个种具有各自特有的基因型。基因型和序列变异分析表明ITS2序列可作为珍珠贝种类鉴定的分子标记。可用于种间、杂交育种、幼体和珍珠贝肉等材料的种类鉴定与遗传分析。     

Fish species richness in lakes of the northeastern lowlands in Germany

Fish species richness was assessed by electrofishing and gillnetting in 16 lakes of the northeastern lowland in Germany (the Schorfheide biosphere reserve). The lakes range from 0.03 to 10.55 km² and support between 5 and 14 fish species. Species richness is significantly correlated with lake area in an exponential and a power model. Richness is also correlated with shoreline development and total dissolved solids. This supports the hypothesis that larger areas contain more species within a taxonomic group due to increased habitat diversity. The slope of the species-area curve is low compared with most other studies of fish species richness in lakes, and the intercept value is high. This is interpreted as the result of high habitat and food diversity, lack of stress from abiotic factors, and the small regional species pool from which these lakes can be colonized. Two species inventories, one from the beginning of this century and one from the 1950s, are available for comparison. Average species richness did not change during the last decades. Species turnover rates were not related to the degree of anthropogenic eutrophication or to the intensity of fishery exploitation in these lakes. On the species level, however, one effect of accelerated eutrophication is apparent, the disappearance of 4 bottom-living species from one to 6 of the study lakes.     

桑园套种油冬菜栽培技术

阐述了桑园套种油冬菜栽培的意义及桑圈套种油冬菜栽培生产的关键技术,以为种植户提供参考。