浅谈磷化氢抗性害虫的成因及治理

西方从宏观和微观两方面介绍了仓库磷化氢抗性害虫的成因，从多角度分析了抗性害虫的方法，提出了实施磷化氢抗性害虫综合治理的策略。     

Effects of Population Density on the Vegetative Growth of Leafy Reduced-stature Maize in Short-season Areas

Maize hybrids which produce more leaves above the ear, with leaf area indices similar to conventional hybrids, which require fewer corn heat units to flowering and maturity, and tolerate higher population densities, should be better adapted for production in short season areas than currently available hybrids. Leafy reduced-stature maize hybrids, which have only recently been developed, have traits which address these criteria. The objective of this study was to evaluate the effects of different population densities (50 000, 100 000, 150 000, and 200 000 plants.ha⁻¹) on the vegetative growth of one leafy reduced-stature (LRS), one non-leafy reduced-stature (NLRS), and two conventional control hybrids (Pioneer 3979, < 2500 CHU, and Pioneer 3902, 2600–2700 CHU) at two locations. There were no differences among population densities for leaf number above the ear; however leaf area index increased as population density increased for all hybrids. The LRS hybrid had a greater average leaf number above the ear (2.7 and 2.0 more leaves than NLRS and the control hybrids, respectively). As a result the leaf area index value of LRS was much greater than the NLRS and similar to the conventional hybrids, but LRS matured substantially before the conventional hybrids. The LRS hybrid required fewer corn heat units to reach flowering and maturity and had more time for grain filling than the conventional hybrids. Therefore, LRS hybrids show promise for production in short season areas where maize cultivation is not economical due to shortness of growing season.     

杆菌肽锌对夏季产蛋鸡生产性能及血液指标的影响

３８０日龄北京白鸡８０只被随机分成２个处理，每个处理４个重复，每个重复１０只鸡，对照组喂基础日粮，试验组在基础日粮中添加５０ｍｇ／ｋｇ杆菌肽锌．试验被安排在１９９８年６月３０日至７月３０日进行．试验结果表明：杆菌肽锌对产蛋鸡平均产蛋量、平均蛋重及饲料转化率没有显著影响，但却可以明显改善蛋壳质量（蛋壳强度、蛋壳厚度）（Ｐ＜０．０５），并显著减少破软蛋率（Ｐ＜０．０１）．而且在夏季（３２℃以上）蛋鸡产蛋率下降阶段可以减少产蛋率的下降幅度．杆菌肽锌对蛋鸡血液中Ｃａ、Ｐ、Ｚｎ及ＡＬＫＰ（碱性磷酸酶）含量的影响不显著．     

3个菠萝品种在低温胁迫下的生理反应

为了研究菠萝的抗寒机制，利用人工气候室，以20℃处理为对照，研究了巴厘、台农17号、澳大利亚卡因3个菠萝品种在15℃、10℃、5℃低温胁迫下3天后叶片可溶性糖、过氧化物酶（POD）和过氧化氢酶（CAT）活性、抗坏血酸(ASA)含量的变化，并调查了植株冻害等级。试验结果表明：低温诱导菠萝体内产生更多的可溶性糖；在低温胁迫下过氧化物酶（POD）活性升高，过氧化氢酶（CAT）活性降低，抗坏血酸(ASA)含量减少；巴厘、台农17号寒害级别为一级，澳大利亚卡因为二级。应采用综合指标鉴定菠萝的耐寒性。     

Characterization of Degraded Soils in the Humid Ethiopian Highlands

Hardpan is a major cause of land degradation that affects agricultural productivity in developing countries. However, relatively, little is known about the interaction of land degradation and hardpans. The objective of this study was, therefore, to investigate soil degradation and the formation of hardpans in crop/livestock‐mixed rainfed agriculture systems and to assess how changes in soil properties are related to the conversion of land from forest to agriculture. Two watersheds (Anjeni and Debre Mewi) were selected in the humid Ethiopian highlands. For both watersheds, 0–45 cm soil penetration resistance (SPR, n  = 180) and soil physical properties (particle size, soil organic matter, pH, base ions, cation exchange capacity, silica content, bulk density and moisture content) were determined at 15 cm depth increments for three land uses: cultivated, pasture and forest. SPR of agricultural fields was significantly greater than that of forest lands. Dense layers with a critical SPR threshold of ≥2000 kPa were observed in the cultivated and pasture lands starting at a depth of 15–30 cm but did not occur in the undisturbed forest land. Compared with the original forest soils, agricultural fields were lower in organic matter, cation exchange capacity, and exchangeable base cations; more acidic; had a higher bulk density and more fine particles (clay and silt); and contained less soluble silica. Overall, our findings suggest that soil physical and chemical properties in agricultural lands are deteriorated, causing disintegration of soil aggregates, resulting in greater sediment concentration in infiltration water that clogged up macro‐pores, thereby disconnecting deep flow paths found in original forest soils. Copyright © 2016 John Wiley & Sons, Ltd.     

厦门筼筜湖游泳生物资源状况

2007年11月和2008年5月,对筼筜湖的游泳生物开展了2个季度的调查.结果显示:调查出现的游泳生物种类有69种.其中鱼类44种,虾类7种,蟹类14种,头足类3种,口足类1种;渔获量的优势种为远海梭子蟹和尼罗罗非鱼,渔获尾数优势种则以硬头鲻和远海梭子蟹为主.湖内刺网平均单位面积渔获量1.0069g/m2·h,单位面积渔获尾数0.0192ind/m2·h.排水口年平均资源指数为1043.317g/网·h,资源密度为148.883ind/网·h.现存资源量为729.752kg,现存资源尾数为10.4168×104尾.调查结果表明,筼筜湖的游泳生物种类比2001年出现的60种和1992年的43种,分别增加15%和60.46%.表明筼筜湖的综合治理取得了明显的生态效果.     

复盐胁迫对几种燕麦种子萌发指数的影响

采用加拿大7种燕麦(A.nuda)种子,在不同梯度的Na2SO4、NaCl等组分盐溶液中进行发芽试验.结果表明:复盐胁迫下,种子开始发芽的时间推迟,发芽过程延长,随着盐胁迫浓度的增加,7种燕麦种子的发芽率、发芽势和发芽指数、简易活力指数均有不同程度的降低,而盐害指数升高,且不同品种间存在显著或极显著差异；随复盐浓度的增...     

大气环流指数和地面气象要素对海南省橡胶树白粉病的影响

为探讨大气环流指数和地面气象要素对海南省橡胶树白粉病病情指数的影响,利用1962—2009年逐月大气环流指数和逐日地面气象要素资料,根据橡胶树白粉病病情指数等级,结合因子膨化、相关分析和多元回归等方法,筛选影响橡胶树白粉病病情指数的大气环流指数和地面气象要素,构建等级指标,建立预测模型,并对模型进行检验。结果显示:影响橡胶树白粉病病情指数的大气环流指数依次为北半球副高面积指数、北半球副高强度指数、西太平洋副高西伸脊点、北美区极涡面积指数、亚洲区极涡强度指数和印缅槽,显著影响时段为上年7月至当年4月;地面气象要素有平均最高气温、相对湿度、平均气温≥20℃的日数、小雨日数和平均风速,显著影响时段为上年10月至当年1月;基于大气环流指数、地面气象要素、大气环流与地面气象综合因子的橡胶树白粉病病情指数预测模型准确率分别为74.3%～78.8%、74.7%、94.6%～98.3%,表明基于大气环流和地面气象综合因子的模型准确率较高,可作为海南省橡胶树白粉病的中长期预测模型。     

干旱胁迫下‘宁玉’草莓生长发育及相关基因表达特点

为分析基因诊断草莓在干旱逆境条件下生长状态的可行性,以‘宁玉’草莓为试材,调查了不同干旱胁迫条件下的生长特点以及与生长素合成、脱落酸合成、花果发育、色素合成相关的10个基因的表达情况。研究结果表明:在不同干旱条件下草莓均可完成从营养生长到生殖生长的生命周期,所选基因也都行使并完成了其调控功能。与对照植株相比,在轻度和中度干旱胁迫(50%~65%土壤持水量)条件下,草莓植株的物候期较对照(80%土壤持水量)提早,而在严重干旱胁迫(35%土壤含水量时)条件下延缓,随着干旱胁迫条件的加重,草莓植株、叶片、果实明显变小,果实着色加深。每个基因在不同干旱条件下表达水平的变化趋势基本一致,且都与相应的物候期以及生长发育时间长短的变化情况相一致,但所选基因在几种干旱条件下其表达开始的早晚、表达水平的高低以及表达相应程度持续时间的长短存在不同。在轻度和中度干旱条件下,这些基因的表达时间提早,但持续时间较短,表达水平高于对照;而在重度干旱条件下,这些基因的表达开始的时间较对照延缓,表达水平较低但持续时间拉长。上述研究结果表明,利用基因的表达信息可以提前推断草莓植株在不同干旱条件下的生长发育状态,了解干旱胁迫对草莓生长发育的影响以及为是否需要提早采取管理措施等提供重要依据。     

基于茎秆直径微变化的拔节期玉米水分亏缺诊断指标研究

为了探索利用茎秆直径微变化诊断玉米水分亏缺状况的最优指标,采用桶栽的方法,开展了不同水分处理条件下拔节期夏玉米茎秆直径微变化中的日最大收缩量(MDS)、日增长量(DI)和当日恢复时间(RT)3个指标的变化规律及其与土壤相对含水率之间相关关系方面的试验研究。结果表明,(1)不同处理间的MDS和DI受水分亏缺影响差异较为明显,RT对土壤相对含水率的响应较为一致;(2)玉米日最大收缩量MDS和日增长量DI受到环境因素的影响较大,与土壤相对含水率θ的相关系数较小;(3)恢复时间RT与土壤相对含水率θ的相关系数最高,且受水分亏缺处理的影响较小,可以作为诊断玉米水分亏缺状况的较好指标。综上可知,与MDS和DI相比,RT更适合诊断夏玉米水分亏缺状况。