西花蓟马在黄瓜和架豆上的空间分布型及理论抽样数

西花蓟马Frankliniella occidentalis（Pergande）已在北京部分蔬菜园区成功定居,对蔬菜生产造成危害。为了解该虫在蔬菜田的种群空间分布型,指导田间取样,本文应用几种聚集度指标的计算公式以及Taylor、Iwao的回归方程式,分析和测定了西花蓟马的种群空间分布格局。结果表明：在黄瓜和架豆上西花蓟马的空间分布型一致,均为聚集分布型;该虫的空间分布型不受种群密度的影响,并且也不随取样时间的变化而变化。种群数量动态研究显示西花蓟马成虫和若虫在黄瓜植株的中部叶片分布较多（从顶部向下数第4叶至第17叶片上成、若虫的分布数量多于其他叶片上的数量）,未展开的叶片、嫩叶和下部老叶危害较轻。用Iwao回归法中α、β参数计算出在允许误差范围内的理论抽样数。     

不同抗性小麦品种上麦红吸浆虫幼虫的空间分布型与理论抽样数

【目的】为了解小麦品种抗性对麦红吸浆虫Sitodiplosis mosellana(Géhin)幼虫在麦穗上空间分布型的影响,为科学调查提供合理的抽样依据。【方法】2015年5月采用剥穗调查法对陕西省周至县试验田种植的4个抗虫和4个感虫小麦品种麦红吸浆虫幼虫危害进行调查,应用6种聚集度指标和Iwao M*?m回归法综合分析了幼虫在抗性不同小麦品种上的的空间分布结构。【结果】幼虫在抗、感小麦品种整穗及麦穗上、中、下部位上空间分布型一致,均呈聚集分布,但在抗虫品种上聚集强度大于感虫品种;抗、感小麦品种上分布的基本成分均为个体群,个体间相互吸引。聚集均数λ分析表明,幼虫在抗性较强品种上的聚集主要由小麦穗部化学物质和形态结构等环境因素引起,感虫品种上则由环境因素和成虫的产卵习性共同作用所致。幼虫在抗、感小麦品种上的发生趋势一致,均是上部发生最重,中部次之,下部最轻。根据Iwao回归法中的分布型参数,确立了幼虫在不同虫口密度和允许误差条件下的理论抽样数。【结论】麦红吸浆虫幼虫在抗性不同小麦品种上均呈聚集分布,调查时应根据当地栽培品种平均虫口密度选择适宜的抽样数量。     

甘蔗蓟马种群动态及其在不同品种甘蔗上为害情况

【目的】明确甘蔗蓟马Fulmekiola serrata的发生动态及其在不同品种甘蔗上的为害情况,为探讨该虫对不同甘蔗品种的选择性和采取有效的防治措施奠定基础。【方法】田间种群动态调查于2013年4月初到7月末进行,研究了12个品种在新植甘蔗和宿根甘蔗田块遭受甘蔗蓟马为害情况。【结果】甘蔗蓟马种群数量先逐渐上升后又下降,发生高峰期集中在6月中旬到7月上旬。12个甘蔗品种均受到甘蔗蓟马为害,其中,新植甘蔗中云瑞06-189甘蔗蓟马数量最多,平均有25.80头/株,闽糖01-77甘蔗蓟马数量最少,平均有7.80头/株;宿根甘蔗中ROC22甘蔗蓟马数量最多,平均有106.93头/株,云蔗06-80甘蔗蓟马数量最少,平均有33.60头/株。同一田块不同品种甘蔗蓟马若虫和成虫数量不等,同一品种宿根甘蔗蓟马数量多于新植甘蔗,株虫量差异范围为10.10~90.90头/株。【结论】甘蔗品种和植期影响甘蔗蓟马发生,不同品种甘蔗蓟马为害程度和抗性水平存在差异。     

垂叶榕榕管蓟马空间分布型及其抽样模型

榕管蓟马（Gynaikothrips uzeli）是观赏植物垂叶榕（Ficus benjamina）的重要害虫。通过对垂叶榕不同方位和高度的随机取样,运用5种聚集度指标以及Taylor幂法和Iwao回归模型分析和测定了榕管蓟马的种群空间格局。结果表明：榕管蓟马虫瘿主要分布于垂叶榕的中、下层,且下层4个方位的虫口密度差异均不显著。榕管蓟马虫瘿在垂叶榕上的理论分布型符合负二项分布,各项聚集度指标均满足CA＞1、IDM＞0、m*/m＞1,且0＜K＜8,表明该蓟马在垂叶榕上的空间分布型为聚集分布,其聚集分布的原因与自身营虫瘿生活及喜阴习性有关。应用Iwao理论抽样模型确定了榕管蓟马不同种群密度与不同精度要求下的理论抽样数。     

杨树上云斑天牛种群的空间格局及抽样技术

云斑天牛Batocera horsfieldi是我国南方杨树的重要蛀干害虫, 研究云斑天牛种群的空间格局和抽样技术, 可为该虫的危害调查与防治提供理论依据。应用Taylor的幂法则、Iwao m*-m回归分析法及6个聚集指标, 对云斑天牛种群的卵、幼虫、蛹或成虫的空间分布型和抽样技术进行了研究, 并做了影响因素分析。结果表明: 云斑天牛的卵、幼虫、蛹或成虫在杨树上均呈聚集分布, 分布的基本成分是个体群, 其聚集性随密度的增加而增大。运用Iwao m*-m回归中的两个参数α和β值, 计算出了在不同精度下以刻槽、排粪孔和羽化孔为防治指标时的理论抽样数据表及序贯抽样数据表,生产中可查阅使用。     

Spatial distribution of Apolygus lucorum in cotton fields

2009-2010年于河北省廊坊市对棉田绿盲蝽Apolygus lucorum(Meyer-Dür)的空间分布型及其抽样模型进行了研究.结果表明,绿盲蝽成虫空间分布型与其种群密度有关,当种群密度大于百株1.6头时呈随机分布,当小于百株1.6头时一般呈聚集分布;绿盲蝽若虫在不同种群密度下均呈聚集分布;绿盲蝽整个种群呈Possion分布.应用Iwao的抽样模型建立了棉田绿盲蝽的理论抽样数公式:N=(1.35/-(x))/D2.     

棉田绿盲蝽的空间分布型及其抽样模型

2009—2010年于河北省廊坊市对棉田绿盲蝽Apolygus lucorum(Meyer-Dür)的空间分布型及其抽样模型进行了研究。结果表明,绿盲蝽成虫空间分布型与其种群密度有关,当种群密度大于百株1.6头时呈随机分布,当小于百株1.6头时一般呈聚集分布;绿盲蝽若虫在不同种群密度下均呈聚集分布;绿盲蝽整个种群呈Possion分布。应用Iwao的抽样模型建立了棉田绿盲蝽的理论抽样数公式:N=(1.35/x珋)/D2。     

三叶斑潜蝇幼虫种群空间格局及抽样技术研究

三叶斑潜蝇Liriomyza trifolii是我国重要的园艺及蔬菜害虫,研究三叶斑潜蝇种群的空间格局和抽样技术,可为该虫的危害调查与防治提供理论依据。应用Iwao m*-m回归分析法、Taylor的幂法则及6个聚集指标,对三叶斑潜蝇幼虫在番茄和豇豆上的空间分布型和抽样技术进行了研究,并做了影响因素分析。结果表明:三叶斑潜蝇幼虫在番茄和豇豆上均呈聚集分布,分布的基本成分是以个体群形式存在,通过分布型参数,采用Kc法、Iwao法及Taylor幂法计算出了在不同精度下三叶斑潜蝇田间的理论抽样数。     

碧桃朝鲜球坚蚧的出蛰若虫空间格局及应用

采用多种聚集度指标、Iwao法和Taylor幂函数法分析朝鲜球坚蚧出蛰若虫在碧桃上的空间格局。结果表明,出蛰若虫在碧桃上呈聚集分布,分布以个体群形式存在。碧桃不同段位上的聚集度指标和Iwao法均表明其为聚集分布,而Taylor幂函数法测定为上、中段均匀分布,下段聚集分布,综合分析其成因是各样地受害程度及垂直方向虫口密度差异显著所致。聚集均数λ值的测定结果表明,该虫的聚集原因主要由出蛰若虫自身的生物学习性和环境因素所引起。此外,利用空间格局参数确定了理论抽样数和序贯抽样模型。     

三化螟为害水稻白穗空间分布型及其应用

本研究探讨了水稻三化螟白穗空间分布格局和抽样技术,为该虫害的监测预报和有效防控提供参考.选取9块水稻田逐丛调查资料,应用6种聚集度指标、 Iwao的m~*—m回归分析法和Taytor幂法则,研究三化螟白穗的空间分布型和抽样技术.结果表明,三化螟白穗在水稻田呈聚集分布,分布的基本成分为个体间相互吸引,其聚集度是随着密度的增加而升高.在此基础上,采用Iwao法确定了三化螟白穗的田间最适理论抽样公式;田间调查时,可用白穗丛率估计白穗种群密度,其公式为■.所建立的理论抽样公式和简易估计公式可在三化螟白穗调查、监测预报和科学防控中推广应用.     

Gibberellins of sugarcane

In our hands a phosphate buffered celite column has given an adequate separation of GA₁ and GA₃. These 2 gibberellins are normally very difficult to separate. Young sugarcane growing under moisture stress contains at least 2 gibberellin-like substances. One is suspected to be GA₅. The other is unknown but has high activity in the barley endosperm assay and is neither GA₁ nor GA₃. Four-month-old cane contains 2 major growth promoters. From their chromatographic, fluorimetric and biological properties these are thought to be GA₁ and GA₃. Rapidly growing 6-month-old cane has a surprisingly low level of gibberellin-like substances.     

Microbial communities in sugarcane field soils with and without a sugarcane cropping history

Microbial communities in rhizosphere soil from sugarcane (Saccharum inter-specific hybrids) and bulk soil were compared at paired field sites with and without a sugarcane cropping history to determine whether monoculture affects soil microbial community composition. Differences were evaluated for culturable microorganisms and functional diversity indicated by community level physiological profiles (CLPP). Qualitative differences in rhizosphere bacterial communities were detected between sites with no sugarcane cropping history (N_site) and sites with a long-term sugarcane cropping history (L_site). More fluorescent pseudomonads were detected in N_site than L_site rhizosphere soil at two of three sites, and Actinobacteria were more numerous in N_site than L_site rhizosphere soil at one site. Fusarial fungi were more numerous in N_site than L_site rhizosphere soils. Bacteria were more numerous in rhizosphere soil compared to bulk soil. Total bacterial, pseudomonad, and Actinobacteria population densities were greater in bulk soil from an N_site compared to an L_site. CLPP distinguished bulk from rhizosphere soil at one of two sites and N_site and L_site rhizosphere soils at two of four sites. Site affected CLPP similarity more than cropping history. The results demonstrated that sugarcane monoculture can affect the composition of the microbial community in field soil. The findings have possible implications for reduced yields associated with sugarcane monoculture.     

Life cycle assessment of Australian sugarcane production with a focus on sugarcane growing

Purpose  

Past life cycle assessments (LCA) of sugarcane (Saccharum officinarum) production have commonly been based on limited datasets, and variability has not been well described. In this work, Australian sugarcane production was assessed more comprehensively in order to generate a robust set of LCA results for use in subsequent assessments of sugarcane products and also to investigate: (1) variability due to regional differences, (2) factors influencing variability, and (3) significance of the impacts.     

A role for sugarcane glycoproteins in the resistance of sugarcane to Ustilago scitaminea

Smut is a major disease of sugarcane caused by Ustilago scitaminea. Germination of fungal teliospores is achieved on the internode surface of plants, and it is followed by the formation of appressoria. A primary response of sugarcane plants to the infection seems to be the production of several glycoproteins, defined as mid-molecular mass (MMMG) or high molecular mass (HMMG) macromolecules. Teliospore germination in the presence of both MMMG and HMMG decreased about 50% following 5 h of teliospore contact with glycoproteins. This may be related to the ability of glycoproteins to produce cytoagglutination. Binding of fluorescein-labelled glycoproteins was studied by fluorescence microscopy, showing that staining of cells was not uniform, but mainly in the contact zone between two individual teliospores when aggregated. HMMG was composed of only one fraction that was completely retained by smut teliospores, whereas three of the five different glycoproteins occurring in the MMMG fraction were retained by teliospore cell walls. Moreover, a unique application of salicylic acid, naturally produced by sugarcane stalks after experimental fungal infection, enhanced the production of both glycoprotein pools. A hypothesis about the role of both HMMG and MMMG as defence glycoproteins is discussed.     

甘蔗花生间作对甘蔗地土壤杂草种子萌发特性的影响

为明确间作对杂草种子库特征的影响,比较研究了自然恢复、花生单作、甘蔗单作和甘蔗花生间作下杂草种子库的特征。结果表明:与花生单作田土壤相比,甘蔗花生间作土壤杂草种子库种类和密度分别降低了44.4%和34.0%;与甘蔗单作田土壤相比,甘蔗花生间作土壤杂草种子库种类和密度分别降低了37.5%和22.7%。与播种前和自然恢复田土壤相比,甘蔗花生间作田杂草种子库优势杂草种类数量显著增加,而种子库密度显著降低。甘蔗花生间作田杂草实际出草量分别占自然恢复田的33.7%、花生单作田的40.9%、甘蔗单作田的55.8%。间作系统影响土壤杂草种子库种类和密度的机制,可能是间作作物与杂草竞争资源及其产生的化感作用抑制杂草。