苜蓿种子空间诱变生物学效应研究初报

[目的]了解苜蓿种子空间诱变的生物学效应。[方法]3个品系的苜蓿种子搭载"实践八号"育种卫星飞行,返地后,对其种子出苗率、株高及生长速度等指标进行测试。[结果]卫星搭载对苜蓿种子有显著的诱变效应,主要表现在子叶畸变、株高变异范围和生长速度等方面。通过初步筛选,在搭载当代获得了高株变异,但该变异是否可遗传还需进一步研究确认。搭载的3个品系在子叶畸变率(10%~18%)、株高变异范围(比对照增加30%~150%)、入选变异高株数(5~7株)等方面不同,说明3个品系的搭载效率存在差异。[结论]通过空间诱变可获得有价值的变异材料,服务于现代农业。     

新疆亚洲玉米螟不同地理种群遗传多样性的研究

为评估新疆亚洲玉米螟(Ostrinia furnacalis)不同地理种群的遗传多样性和遗传分化水平,利用6对微卫星引物对新疆伽师县、拜城县、昌吉三平农场、哈密市和伊宁县等5个区域的亚洲玉米螟种群进行遗传多样性分析。在6个位点获得133个等位基因,各位点平均等位基因数为5.666个,各种群的等位基因数在(A)25～30,平均多态信息含量(PIC)为0.523 0,平均期望杂合度(He)为0.411 5～0.735 2,平均观测杂合度(Ho)为0.414 8～0.527 8。Fst值为0.033 8～0.219 1,整体存在较高的遗传分化。分子方差分析(AMOVA检验)结果显示,群体遗传变异中,种群间的变异占11%,种群内个体的变异占22%,个体内的变异占67%。结果表明,新疆地区亚洲玉米螟种群的遗传多样性较高,种群间存在明显的遗传分化现象,其中伊宁群体遗传多样性最丰富,与其他种群的遗传差异较大。     

苜蓿旱作栽培品种比较试验(1988～1990)

本文介绍了在乌鲁木齐冬季严寒,夏季酷热,年降水量230mm左右,在旱作栽培的条件下,进行了6个苜蓿品种的正规比较试验。历时三年,以产量、草质、越冬率、生长速度及再生等性状比较,以图牧二号紫花苜蓿(Medicago staiva L)阿勒泰杂花苜蓿(M.varia Martyn)石河子杂花苜蓿(M.varia Martyn)表现最好,其次是贝维尔杂花苜蓿(M.varia Martyn)。     

新疆北部地区(北疆)苜蓿属植物秋眠性的研究

以紫花苜蓿栽培品种为对照,对新疆北部地区(北疆)28份四倍体苜蓿属植物种群即紫花苜蓿(Medicago sativa)、黄花苜蓿(M.falcata)、多变苜蓿(M.varia)的秋眠性进行了研究.结果表明,北疆苜蓿属植物种群和国内紫花苜蓿种群相对秋眠性等级值水平为1～3级,其中野生种群表现为极秋眠性(1级),反映了中国苜蓿种质资源蕴藏着较强的抗寒性种质.针对我国苜蓿属植物资源研究现状和国际研究趋势,提出了加强秋眠性研究的建议.     

玉米田除草剂的选择与使用

一、主要除草剂单剂种类（一）酰胺类除草剂 该类产品是目前玉米田最为重要的一类除草剂,可以被杂革芽吸收,在杂草发芽前进行土壤列闭处理,能有效防治年生禾本科杂草和部分一年生阔叶杂草。该类除草剂品种较多,如乙草胺、甲草胺、丁草胺、异丙甲草胺、异丙草胺等。     

南京大豆田间耐草甘膦杂草的种类与特性鉴定

抗草甘膦杂草对农业生产的经济及生态效益均有潜在的不利影响,我国相关研究较少,其种类分布及形成规律有待研究。对南京农业大学江浦农学站大豆试验地田间杂草对除草剂草甘膦耐性反应特点进行田间及室内形态鉴定。结果表明:有14种杂草对草甘膦存在耐性,耐性杂草各具特点,具有粗壮根茎、蜡质叶片等特性,其中铁苋菜等杂草种群大,不同个体存在从死亡到生长正常的不同变异;耐草甘膦紫菀植株衍生后代室内鉴定并不耐草甘膦,其田间抗药性可能与植株形态有关。说明杂草可通过植株形态、内在遗传基础等应对除草剂草甘膦的逆境。一些耐性杂草种群个体间的抗性反应存在明显变异,长期选择下可能成为抗性杂草。耐性杂草苗期抗性最弱,是杂草防除最佳时期。     

苜蓿新品种(系)的抗旱性综合评价

为了综合评价苜蓿新品种(系)的抗旱性,对不同苜蓿品种(系)的蓿产量、电导率、叶绿素含量、CAT活性、POD活性、SOD活性、可溶性蛋白含量、可溶性糖含量、MDA含量、脯氨酸含量等指标进行研究,通过聚类分析方法对不同苜蓿品种(系)的抗旱性进行客观评价。结果表明,抗旱性从强到弱的顺序为:杂选1号苜蓿巨人苜蓿陇中苜蓿中兰1号苜蓿CK×杜苜蓿CK×图苜蓿CK×埃苜蓿。     

短花针茅荒漠草原群落优势种群空间格局分析

采用地统计学分析方法,研究内蒙古短花针茅草原优势种群短花针茅(Stipa breviflora)种群、无芒隐子草(Cleistogenes songorica)种群、冷蒿(Artemisia frigida)种群、银灰旋花(Convolvulus ammannii)种群在中小尺度不同方向的盖度空间分布的类型及其空间变异.结果表明:各优势种种群在中小尺度均呈聚集分布.相同尺度不同方向、相同方向不同尺度的空间分布格局变化明显.相同尺度种群格局的各向异性比也存在差异.小尺度种群格局的变化主要受放牧和种群的繁殖特性影响,在大尺度不同方向的种群空间格局比较中,地形因素、地貌、土壤异质性等成为影响空间格局的主要原因.     

不同景观尺度对杨盾蚧种群空间分布的影响分析

【目的】研究不同景观尺度(不同景观结构/不同生境)下杨盾蚧种群空间格局差异,为合理配置景观要素组成、进行杨盾蚧防控工作提供理论基础。【方法】利用ArcGIS进行景观要素分类,计算景观指数,基于GS利用地统计学建立空间模型。【结果】不同景观半变异函数模型各不相同,其中高斯模型(LS1)与指数模型(LS5)存在显著性差异;景观多样性指数与景观均匀度指数对杨盾蚧的空间分布无直接影响,平均面积周长比与杨盾蚧的平均虫口密度呈现负相关。不同生境中,杨盾蚧种群均呈现聚集性,建立的半方差函数模型分别符合高斯模型和指数模型。在林地生境中,杨盾蚧种群平均虫口密度较小,空间上存在较高的连续性,变异能力较弱;在农田边缘生境中,平均虫口密度较大,空间变异能力较强,聚集性也较强。【结论】人工(农耕、灌溉、除草等)干扰造成景观破碎化,景观要素的组成与配置的共同影响一定程度上控制了杨盾蚧种群的扩散与发展。     

放牧和刈割对大针茅草原羊草空间异质性的影响

【目的】分析不同利用方式下小尺度羊草种群的空间异质性及其分布,为草地的可持续利用提供参考。【方法】以大针茅典型草原优势种羊草为研究对象,基于地统计法,利用变异函数、空间自相关系数、分形维数以及克里格插值法,分析放牧、刈割和围封(对照)利用方式下羊草种群空间异质性的变化。【结果】放牧可显著提高羊草种群密度(P0.05),3种利用方式下羊草种群密度均值表现为放牧(48.38株/m~2)围封(12.53株/m~2)刈割(7.51株/m~2)。不同利用方式下,羊草种群空间分布的最优模型均为球状模型,羊草种群空间异质性表现为围封放牧刈割,羊草种群的空间分布格局主要受结构性因素的影响。在围封样地中,羊草种群呈现出较小尺度内变异较大的带状分布;在放牧样地中,羊草种群呈现出较大尺度内变异较小的片状分布;在刈割样地中,羊草种群以变异性大的高密度点状斑块镶嵌于平坦的低密度斑块上,呈现点状分布。【结论】放牧和刈割对大针茅草原羊草种群密度和空间异质性均有影响。     

An on-farm approach to quantify yield variation and to derive decision rules for site-specific weed management

Grain yield often varies within agricultural fields as a result of the variation in soil characteristics, competition from weeds, management practices and their causal interactions. To implement appropriate management decisions, yield variability needs to be explained and quantified. A new experimental design was established and tested in a field experiment to detect yield variation in relation to the variation in soil quality, the heterogeneity of weed distribution and weed control within a field. Weed seedling distribution and density, apparent soil electrical conductivity (EC_a) and grain yield were recorded and mapped in a 3.5 ha winter wheat field during 2005 and 2006. A linear mixed model with an anisotropic spatial correlation structure was used to estimate the effect of soil characteristics, weed competition and herbicide treatment on crop yield. The results showed that all properties had a strong effect on grain yield. By adding herbicide costs and current grain price into the model, thresholds of weed density were derived for site-specific weed control. This experimental approach enables the variation of yield within agricultural fields to be explained, and an understanding of the effects on yield of the factors that affect it and their causal interactions to be gained. The approach can be applied to improve decision algorithms for the patch spraying of weeds.     

烟田莎草的空间分布型与抽样技术

结果表明 ,烟田莎草呈明显的聚集分布 .利用有草样方频率和空间格局特征参数对烟田莎草种群密度进行估测 ,建立了相应的理论抽样数模型     

Two-Year Weed Seedling Population Responses to a Post-Emergent Method of Site-Specific Weed Management

Field experiments were conducted to determine how a site-specific weed management practice in Zea mays L. influenced the numerical and spatial distribution of a naturally occurring weed infestation in Z. mays and the succeeding Beta vulgaris L. crop. Compared to conventional broadcast herbicide applications, site-specific herbicide applications reduced herbicide load by 11.5 and 98.0% in two separate Z. mays fields. The broad range in outcomes was attributed to the spatial aggregation and density of target weed populations. While herbicide use was successfully reduced at field locations with low weed density, most survivors of multiple control tactics were in locations with the highest initial density. A greater understanding of interactions between weed management and weed density would increase the likelihood that site-specific weed management offers long-term improvements over conventional approaches.     

烟田茴茴蒜的空间分布型和抽样技术研究

测定结果表明 ,烟田茴茴蒜的空间分布型为聚集分布 ;利用有草样方频率和空间分布的特征对烟田茴茴蒜的种群密度进行估测 ,并建立了相应的理论抽样数模型和序贯抽样模型 ;对不同抽样方式进行比较 ,得出采用分行式抽样效果最佳 ,而用Z字形抽样效果最差     

Site-Specific Weed Control in Maize,Sugar Beet,Winter Wheat,and Winter Barley

A four-year study of site-specific weed control is presented in this paper. Weed seedling distribution was sampled and mapped prior to and after post-emergence herbicide application in four fields planted with maize, sugar beets, winter wheat and winter barley, rotating on one site. Herbicides and other weed control strategies were applied site-specifically according to the spatial variation of weed populations. Different decision algorithms were used for chemical weed control methods in each crop. A weed treatment map was created to direct location and dosage of herbicide application. The sprayer was coupled with a differential Global Positioning System (DGPS). The solenoid valves of the sprayer were opened automatically when the tractor entered a weed patch characterized in the weed treatment map. For site specific herbicide application, a patch sprayer was developed that allowed variable rate application and the selective control of each section of the spray boom.     

长苞铁杉种群空间格局的分形特征

种群格局关联维数是种群个体空间关联尺度变化规律的反映,表明了种群个体的空间相关程度。采用关联维数对福建省天宝岩国家级自然保护区珍稀濒危植物长苞铁杉种群格局的分形特征进行了研究。结果表明,不同样地长苞铁杉种群个体空间关联的无标度区介于1-32 m,种群格局关联维数值1.032 4-1.580 1,不同样地种群关联维数的大小为Q5>Q1>Q2>Q4>Q6>Q3,从而揭示出长苞铁杉在不同样地中个体空间关联尺度变化的差异。     

Modelling Wild-Oat Density in Terms of Soil Factors: A Machine Learning Approach

In crop fields, weed density varies spatially in non-random patterns. Initial knowledge of weed distribution would greatly improve weed management for Precision Agriculture operations. Site properties could be correlated to weed distribution, since the former vary among crop fields and also certain factors such as soil texture or nitrogen may condition the weed growth. This paper presents a method, based on artificial intelligence techniques, for inducing a model that appropriately predicts the heterogeneous distribution of wild-oat (Avena sterilis L.) in terms of some environmental variables. From several experiments, distinct rule sets have been found by applying a genetic algorithm to carry out the automatic learning process. The best rule set extracted was able to explain about 88% of weed variability.     

麦红吸浆虫区域分布的GIS分析

运用灌浆期麦穗幼虫调查方法、地学统计学方法以及地理信息系统(GIS),对河南省北部新乡市辉县高庄乡小麦灌浆期麦红吸浆虫(Sitodiplosis mosellana)老熟幼虫种群的空间结构进行了分析,并采用普通克里格插值法模拟了吸浆虫老熟幼虫种群的空间分布.结果表明:辉县高庄乡小麦灌浆期麦红吸浆虫幼虫种群存在空间相关性...     

贵州雷公山秃杉种群格局的分形特征——信息维数

应用分形理论中的信息维数探讨了贵州雷公山秃杉种群格局的分形特征。结果表明:秃杉种群的格局具有分形特征。5个样地的秃杉种群的信息维数大小依次为:Q5(1.428 0)>Q4(1.002 7)>Q3(0.828 3)>Q2(0.772 5)>Q1(0.715 9),这种差异反映了秃杉种群在各群落中更新状况的差异。信息维数揭示了秃杉种群格局强度的尺度变化程度和种群个体分布的非均匀性,适用于秃杉种群分布格局分形特征的定量描述。     

外来入侵植物的危害及防治

综述了外来入侵植物的生态危害、经济损失、生态学特征、入侵途径与扩散机制,并提出了检疫防治、人工防治、物理防治、化学防治、生物防治和综合防治等措施。