DDVP对泥鳅的致毒效应

采用室内培养实验方法，研究了DDVP对水生生物泥鳅的致毒效应。毒性实验表明，DDVP可诱发泥鳅血红细胞和卵细胞畸形，并抑制或阻止细胞的正常分裂和发育，显示较强的雌激素活性。     

Evaluation of Sensitivity to Phoxim and Cypermethrin in an Endoparasitoid,Meteorus pulchricornis (Wesmael) (Hymenoptera: Braconidae), and Its Parasitization Efficiency Under Insecticide Stress

Insecticides can have consequences for beneficial arthropods. Insect parasitoids can contact insecticides through direct exposure spray droplets or residues on crop foliage. Here, we focus on better understand the response of Meteorus pulchricornis (Wesmael), a parasitoid wasp of lepidopteran pests, and its detoxification mechanisms on stress caused by phoxim and cypermethrin. Hence, we determined the dose–mortality curves and estimating the sublethal concentrations (LC₃₀ and LC₅₀). Then, we applied the sublethal concentrations against adult parasitoids to assess its survival, parasitism efficacy, and also developmental and morphometric parameters of their offspring. Simultaneously, we check the activities of glutathione S-transferase (GST), acetylcholinesterase (AChE), and peroxidase (POD) after sublethal exposure of both insecticides, which has measured until 48 h after treatment. Overall, phoxim and cypermethrin exhibited acute lethal activity toward the parasitoid with LC₅₀ values 4.608 and 8.570 mg/liter, respectively. Also, we detect that LC₃₀ was able to trigger the enzymatic activity of GST, AChE, and POD, suggesting a potential detoxification mechanism. However, even when subjected to sublethal exposure, our results indicate strong negatives effects, in particular for phoxim, which has affected the parasitism efficacy and also the developmental and morphometric parameters of M. pulchricornis offspring. Therefore, it can be concluded that both phoxim and cypermethrin have negative impacts on M. pulchricornis and we suggest cautioning their use and the need for semifield and field assessments to confirm such an impact.     

基于HYDRUS-1D模型的河套灌区典型夹砂层耕地水分利用分析

为研究夹砂层耕地水分利用规律,以河套灌区典型夹砂层土壤耕地为研究对象,利用在春玉米生育期田间监测数据,应用土壤水分运动数值模型,探究对夹砂层土壤田间蒸散发、作物耗水及深层土壤水分的补给与深层渗漏规律。选择2种土壤的夹砂层埋深梯度S1（40～95 cm）、S2（60～110 cm）,设置了3个灌水水平W1（252.5 mm）、W2（315.85 mm）、W3（378.75 mm）开展田间试验,同不含夹砂层处理B作对照,并应用HYDRUS-1D模型模拟春玉米生育期田间蒸散发,土壤水分深层渗漏及地下水补给耕层水量与根系吸水量,与不含夹砂层处理对比分析夹砂层对田间水分利用影响。结果表明：随着砂层埋深增加,棵间蒸发损失减小,叶面蒸腾水量增加;不含夹砂层处理玉米田间毛管向上补给水量较浅埋砂层与深埋砂层处理分别大57.01%、118.53%,灌水量为315.85 mm时含夹砂层处理的土壤水分深层渗漏最小;玉米生育期内根系吸水量随砂层埋深的增加而减少,不含夹砂层处理根系吸水量最大。浅埋砂层与深埋砂层处理分别为蒸散量的55.51%、61.31%,不含夹砂层处理为66.69%;暂时性亏缺水量从大到小依次为：S2、S1、B,水分从大到小依次为：B、S2、S1。综合考虑夹砂层土壤水分迁移、作物水分利用规律,建议在夹砂层耕地春玉米灌溉根据砂层分布因地制宜定灌溉制度,当夹砂层埋深在40～110 cm范围时,推荐春玉米在生育期灌溉定额为315.85 mm。该研究结果可为河套灌区含有夹砂层农田灌溉制度的制定提供理论指导。     

基于无人机影像的冠层光谱和结构特征监测甜菜长势

甜菜是中国北方地区重要的经济作物。快速、准确、高通量的获取甜菜的地上部和块根鲜质量、块根含糖率、叶绿素含量对甜菜生产具有重要意义。该研究采用无人机搭载数码和多光谱相机,获取甜菜叶丛快速生长期、块根及糖分增长期和糖分积累期的数码影像和多光谱影像,提取了冠层的结构特征和光谱特征。选择随机森林回归（Random Forest Regression,RFR）和偏最小二乘回归（Partial Least Squares Regression,PLSR）2种建模方法基于获取的冠层特征,构建甜菜全生育期的地上部和块根鲜质量、块根含糖率和SPAD（Soil and Plant Analyzer Development）值估算模型。研究结果表明,随机森林回归模型和偏最小二乘回归模型对地上部和块根鲜质量、含糖率都做出较好的预测,R2范围分别为0.9～0.94、0.88～0.9,rRMSE范围分别为7.6%～17%、8.8%～20%。对SPAD值的预测均较弱,R2分别为0.66和0.67。为了减小输入变量集的大小以及去掉对预测不敏感的变量,该研究采用置换重要性（Permutation Importance,PIMP）来筛选冠层光谱特征和结构特征中对预测有重要影响的变量。结果表明基于筛选出的重要性特征构建的随机森林回归模型和偏最小二乘回归模型对地上部和块根鲜质量、含糖率都做出较好的预测,R2范围分别为0.89～0.94、0.74～0.91,rRMSE范围分别为7.3%～19%、7.6%～19%。对SPAD值的预测均较弱,R2分别为0.65和0.68。进一步表明随机森林回归模型在精度上略好于偏最小二乘回归模型。同时基于PIMP筛选变量的方法在保持原有精度的同时能实现降低数据收集复杂性的目的。研究结果为基于无人机遥感技术快速、准确监测甜菜长势和估测块根类作物的根部活性物质提供了参考。     

凤丹牡丹花粉和花药壁营养成分分析及评价

为探明凤丹牡丹花粉、花药壁的营养成分,从而更好地发挥其营养价值,本研究采用凯氏定氮法、电感耦合等离子体发射光谱、高效液相色谱、氨基酸分析仪等对凤丹花粉和花药壁蛋白质、矿物质元素、维生素C、水解氨基酸及游离氨基酸进行了系统地分析和评价。结果表明,凤丹花粉中蛋白质含量高达40.68%(初开期),水解氨基酸总量为355.65 mg·g^-1(初开期),花药壁中蛋白质和水解氨基酸的总量虽仅为花粉的一半,但二者必需氨基酸与总氨基酸的比值均为40%左右,属优质蛋白来源。36种游离氨基酸检测结果显示,花药壁中总游离氨基酸含量稍高,但花粉中必需氨基酸、蛋白氨基酸及鲜甜氨基酸含量更高。矿物质元素分析结果表明,凤丹花粉、花药壁含有丰富的常量和微量元素,尤以K、Ca、Mg、Fe、Zn等元素含量较高,是开发高钾低钠和补铁补锌的佳品。Vc测定结果显示,凤丹花粉和花药壁中Vc含量较高,可作为Vc补充剂。同时考察了凤丹花粉、花药壁不同采收时期及破壁对检测成分含量的影响,结果显示二者更适合在初开期采收,且破壁对花粉、花药壁营养成分检测无显著影响。综上,凤丹花粉、花药壁含有丰富的营养成分,本研究将为...     

Accumulation of soil organic carbon in aggregates after afforestation on abandoned farmland

To understand how organic C (OC) accumulates in afforested soils and to quantify the contribution of aggregate-associated OC to OC accumulation, we investigated the changes in soil structure, total soil OC, and aggregate-associated OC from 0- to 10- and 10- to 20-cm depths in afforested forests and adjacent farmlands of northwestern China. We assessed the contribution of macroaggregate-associated OC increase to total soil OC accumulation. Afforestation increased macroaggregate amount, mean weight diameter, and mean geometric diameter but decreased the amount of microaggregate and silt + clay-sized fractions. The improvement of soil structure was greater in surface than subsurface soils and was greater in soils afforested with white birch than in soils afforested with other tree species. Fifty years after afforestation, total soil OC concentrations and stocks and aggregate-associated OC concentrations increased depending on soil depth and tree species. Afforestation increased macroaggregate-associated OC stocks but decreased microaggregate- and silt + clay-associated OC stocks. Soil OC stocks and changes in OC stocks after afforestation mainly depended on macroaggregate-associated OC stocks and their changes. The results from this study suggest that OC accumulation in afforested soils is due to the accumulation of OC in macroaggregates and the redistribution of OC from fine particles to coarser fractions.     

有机肥质量分数对土壤导水率稳定性的影响

饱和导水率是水循环和土壤侵蚀模型中的重要参数,也是土壤结构改善的重要指标.通过室内土柱模拟实验研究有机肥添加量对风沙土和壤土导水率的影响.土壤添加有机肥的比例设置为0％、5％、10％、15％、20％、25％、30％7个水平,土壤密度设3个水平,各处理5个重复.结果表明：1）土壤饱和导水率随有机肥质量分数的增加呈降低趋势,风沙土的饱和导水率随有机肥质量分数的增加呈直线下降趋势,而壤土饱和导水率的降低趋势随有机肥质量分数的增加减缓;2）有机肥质量分数的增加对土壤密度的降低作用可以抵消有机肥增加导致的饱和导水率的降低;3）低土壤密度下土壤导水率随时间变化不稳定,土壤密度增大后随时间变化稳定.随着有机肥质量分数的增加,土壤导水率的测定过程趋于稳定,但是测定时间延长.     

番茄褪绿病毒与番茄黄化曲叶病毒复合侵染对番茄褪绿病毒传播的影响

番茄褪绿病毒Tomato chlorosis virus(ToCV)是一种由烟粉虱Bemisia tabaci传播的正义单链RNA病毒,在田间常与番茄黄化曲叶病毒Tomato yellow leaf curl virus(TYLCV)复合侵染而造成番茄生产上重大的经济损失。为了明确ToCV与TYLCV的复合侵染对烟粉虱传播ToCV所造成的影响,本文采用RT-PCR以及qRT-PCR检测了复合侵染的番茄对烟粉虱获取和传播ToCV的影响。研究表明,烟粉虱取食复合侵染的番茄后对ToCV的传播效率显著提高,仅25头烟粉虱的传毒率即可达到100%,ToCV在烟粉虱以及番茄体内的累积量均显著提高。说明这种复合侵染促进了烟粉虱对ToCV的传播,在田间应当及时防控烟粉虱,警惕病毒与烟粉虱的蔓延。     

基于转录组分析的九种苍耳分子标记筛选和鉴定

为实现我国非重要的检疫性杂草——苍耳属Xanthium杂草快速高效的分子鉴定,利用Illumina二代测序平台对白苍耳X.albinum、意大利苍耳X.italicum、直刺苍耳X.ripicola、刺苍耳X.spinosum、柱果苍耳X.cylindricum、宾州苍耳X.pennsylvanicum、蝟实苍耳X.echinatum、苍耳X.sibiricum和北美苍耳X.strumarium共9种苍耳属杂草进行转录组测序,获得的unigene序列数分别为103 362、93 506、87 452、83 822、70 994、66 397、57 598、57 164和57 134个。利用生物信息分析方法对9种苍耳属杂草转录组进行简单重复序列（simple sequence repeat,SSR）和物种间的特异性序列预测和筛选。经过PCR试验验证,筛选获得了可以有效鉴定上述9种杂草的6对SSR引物和13对特异性引物,提高了苍耳属杂草鉴定的准确率。     

害虫生物防治综合效益评价方法

害虫生物防治效果的评价方法通常采用化学防治效果的计算方法,一般仅体现短期内对目标害虫的致死作用结果,而忽略了天敌在自然界数量增殖后对害虫种群数量的长期而持续的控制效果,以及在保护生态环境、保护生物多样性等方面的评价。判断害虫生物防治计划是否获得成功,目前缺乏广泛认同的评价方法。本文对害虫生物防治效果的评价方法进行了梳理,并分析了各种方法可用于害虫生物防治效果评价的可行性及其优缺点。在此基础上,利用层次分析法建立了一套评价害虫生物防治综合效益的指标体系,并应用此方法结合国内外害虫防治包括生物防治的案例进行了比较分析,初步提出了害虫生物防治项目成功与否的评价方法和标准。