草地螟一代幼虫发生面积的气象预报模型

利用内蒙古兴安盟1996-2009年草地螟发生资料和同时段气象资料,分析了草地螟一代幼虫发生面积与气象因子的相关关系,确定了影响草地螟一代幼虫发生面积的主要气象因子;以春季越冬代成虫数量即野外调查的百步惊蛾量和通过相关检验的气象因子为基础,采用多元回归方法建立了草地螟一代幼虫发生面积的气象预报模型。结果表明,一代幼虫发生面积与5月中、下旬相对湿度以及6月中旬平均温度呈正相关,与5月中旬-6月上旬温度以及6月中旬相对湿度呈负相关。通过模型历史回代检验,模拟等级与实际等级完全一致的占77%,与实际相差一个等级的占15%,3级及其以上（中度以上）发生年份的模拟准确率达到100%。通过对2009年草地螟发生面积的试报检验,预报效果较好。利用模型的预报结果可为提前了解草地螟一代幼虫的发生趋势、有效指导当地草地螟防控工作提供参考。     

冬前积温对河南省小麦冬前生长发育的影响

为了给播期调整和提高自然资源利用率提供科学依据,在大田试验条件下,以3个半冬性和3个弱春性小麦品种为供试材料,对冬前积温为350~900℃.d范围内的小麦冬前生长发育进行了分析。结果得出:①播种-出苗的天数和所需积温随着冬前积温的降低而增加,冬前积温每降低100℃.d,播种-出苗天数约增加0.7d,所需积温约增加3.7℃.d(半冬性)或2.5℃.d(弱春性);②冬前积温与冬前主茎叶龄和冬前每叶积温均呈显著正相关(P0.01),冬前积温每降低100℃.d,冬前主茎叶龄约减少0.9片(半冬性)或1.0片(弱春性),每叶积温减少5.0℃.d左右;③随冬前积温的降低,幼穗分化进入单棱期和二棱期的时间推迟,单棱期持续天数增加而二棱期持续天数减少,冬前积温每降低100℃.d,单棱期平均增加10.0d(半冬性)或12.9d(弱春性),二棱期平均减少15.5d(半冬性)或17.4d(弱春性)。结论为,符合冬前壮苗叶龄指标的适宜冬前积温为550~750℃.d(半冬性)和450~600℃.d(弱春性),保证小麦以二棱期安全越冬的适宜冬前积温为650~800℃.d(半冬性)和550~700℃.d(弱春性),从叶龄指标和安全越冬两方面考虑,河南省小麦适宜冬前积温范围为650~750℃.d(半冬性)和550~600℃.d(弱春性)。     

江西省稻瘟病发生潜势的气象预报模型

基于1981-2010年江西省市（县）级稻瘟病监测资料和同期气象资料,利用符号相关法,分苗瘟、叶瘟、穗瘟分析各时期病害发生程度与气象因子的关系,并分别建立病害发生潜势气象预报模型。结果表明：与病害高峰同期的气象因子之间,早稻苗瘟与4月份的平均气温、雨量、日照时数呈正相关,与相对湿度呈负相关;早稻叶瘟与5月中旬-6月上旬的平均气温、雨量、日照时数呈负相关,与相对湿度呈正相关;早稻穗瘟与6月上旬-7月上旬的平均气温、日照时数呈负相关,与雨量、相对湿度呈正相关。晚稻苗瘟偏重发生的概率随着苗期高湿天数和雨日的增加而增大;晚稻叶瘟与8月中旬-9月上旬的平均气温、日照时数呈负相关,与雨量、相对湿度呈正相关;晚稻穗瘟与9月平均气温、相对湿度呈正相关,与雨量、日照时数呈负相关。通过相关关系和符号相同、相反的概率差值确定各气象因子距平值的量化值和权重系数,计算稻瘟病发生潜势气象指数,建立稻瘟病发生潜势气象预报模型。历史回代检验表明,模型准确率为60%～75%,且对偏重级别的准确率高于偏轻级别。     

基于寒露风时空特征的湖南双季晚稻抽穗扬花安全期分析

根据湖南省地方标准,以连续3d或以上日平均气温≤20℃、≤22℃分别作为常规稻和杂交稻的寒露风指标。利用湖南省96个气象站1951年(建站)-2010年每年9月的日平均气温资料,统计寒露风发生最早初日、50%保证率初日、80%保证率初日和9月份的逐日发生频率。结果表明,≤20℃寒露风的初日比≤22℃初日迟7~10d,≤20℃寒露风在9月上旬的逐日发生概率5%、中旬发生概率10%,下旬发生概率明显增加;≤22℃寒露风在9月8日前的逐日发生概率5%,之后随着时间的推移,发生概率呈线性增加。综合安全齐穗期80%的保证率和逐日频率分析,湘北、湘中双季晚稻齐穗期可在原定日期基础上适当后延3~5d,不论是常规稻还是杂交稻,均可由原来的早熟品种改为中迟熟品种。     

凉山州5—7月气象因素对马铃薯晚疫病发生流行的影响

根据2007年在凉山州冕宁的城厢(海拔1823m)、拖乌(海拔2144m)、昭觉的庆恒(海拔1659m)、上游(海拔2571m) 4个点各5期的马铃薯晚疫病发生程度的地理分期播种试验资料,研究凉山州马铃薯晚疫病发生、流行的气象成因和动态特征.结果表明,马铃薯晚疫病发生、流行的主要时期在5月下旬-7月初;5月中旬-6月上旬,若出现连续降雨日在5d以上、并且相对湿度连续6d以上超过75%的情况,一般在5～10d后有可能发生晚疫病.因此,建议以此作为马铃薯晚疫病防治的预警指标,以便在预警指标出现后的5d之内积极组织防治,以提高防治效果.     

下限温度对北京樱花盛花始期模拟效果的影响

利用实际物候观测资料,通过人为设定不同生长发育下限温度值,比较不同指标对应发育阶段所需积温的稳定性和物候模拟准确率,是鉴定植物生长发育下限温度指标的常用统计方法。利用1998-2014年北京市海淀区玉渊潭公园樱花盛花始期观测资料,在设定下限温度0.0～5.0℃范围内,以0.1℃为步长,分别统计历年1月1日-樱花盛花始期的阶段活动积温和有效积温,对比分析不同温度指标对两种模型阶段积温稳定性和发育期模拟准确率的影响。结果表明：（1）阶段积温随设定下限温度指标而变化,且阶段活动积温值及其年际变化值均大于有效积温;（2）两种积温的标准差以活动积温的标准差较大,表明采用有效积温测算樱花盛花始期的误差小于活动积温测算结果;阶段有效积温在设定下限温度0.0～2.9℃范围内变异系数较小,3.0℃及其以上时活动积温的变异系数小于有效积温,活动积温离散程度更小;（3）不同设定下限温度值的始花期预测结果,均以2～3℃的准确率较高。对应设定下限温度0.0～3.2℃范围,有效积温模拟始花期基本准确率（误差小于3d）和准确率（误差2d以内）均大于活动积温模拟结果,但设定下限温度＞3.8℃时结果相反。设定下限温度处于3.3～3.8℃时,有效积温模拟误差的基本准确率大于活动积温,误差小于2d准确率则低于活动积温。综上所述,无论活动积温还是有效积温,均以设定下限温度2.0～3.5℃的计算结果标准差和变异系数最小,准确率较高,在未进行生理测定的条件下,可将其作为樱花盛花始期的下限温度指标。     

基于机器学习算法的冬小麦始花期预报方法

该研究采用机器学习算法,明确冬小麦始花期的主要气象影响因子,并建立始花期预报模型。基于1980-2019年江苏省10个观测点冬小麦生育期观测资料和逐日气象数据,应用随机森林(Random Forest,RF)、反向神经网络(Back Propagation,BP)、多元线性回归(Multiple Linear Regression,MLR)3种算法分别建立始花期预报模型,以决定系数、均方根误差、预报准确率为评判指标,对模型模拟精度进行比较分析。结果表明,温度类因子对始花期影响的重要性明显大于降水类和日照类。基于筛选出的重要特征变量,3种算法建立的始花期预报模型均可在4月初对始花期进行预报,最迟可提前5d预报,最早可提前32d预报;RF算法模拟精度最高,BP算法次之,MLR算法相对低一些;RF算法能准确模拟出始花期波动趋势,大部分站点的始花日期预报准确率都在85.0%以上,表明RF算法在始花期预报中有较高的可靠性和业务应用潜力。     

基于关键气象因子的中稻单产动态预报

利用重庆市1986-2009年中稻单产和中稻生育期内旬平均气温、旬降水量、旬日照时数等资料,采用统计分析法建立中稻气象产量动态预报模型,在此基础上预报中稻单产。用5a滑动平均方法分离中稻趋势产量,在分析气象产量与中稻全生育期逐旬气象要素相关性的基础上,以3月中旬平均气温、5月下旬日照时数、7月中旬平均气温、7月中旬降水量、7月中旬日照时数、7月下旬平均气温、7月下旬降水量和8月上旬平均气温等作为关键气象因子,建立中稻气象产量动态预报模型,并应用该模型实现中稻单产动态预报。对1986-2009年的中稻单产做模拟检验,平均准确率在96%以上,95%以上的年份预报准确率超过90%。对2010年的单产进行预报,准确率为91.5%～92.8%,预报准确率较高,基本能满足业务服务的需要。     

枇杷幼果冻害低温等级指标的确定

根据福建省近5a枇杷幼果低温箱试验和低温过程山坡地枇杷冻害观测试验结果,以及主产省福建、浙江历史灾情资料,采用归纳分析和对比印证等方法,对枇杷幼果冻害的低温等级指标进行研究。结果表明：枇杷幼果冻害低温等级指标可用日最低气温（Tmin）和低温持续天数（DD）表示,各级冻害指标分别为,轻度：-2.5℃＜Tmin≤-1.0℃,DD≤3d;中度：-3.5℃＜Tmin≤-2.5℃,DD≤3d或-2.5℃＜Tmin≤-1.0℃,DD＞3d;重度：-4.5℃＜Tmin≤-3.5℃,DD≤3d或-3.5℃＜Tmin≤-2.5℃,DD＞3d;极重：Tmin≤-4.5℃,DD≤3d或Tmin≤-3.5℃,DD＞3d。历史灾情资料验证结果表明,冻害等级指标在福建莆田的推算准确率为61%,在浙江临海、黄岩为87.5%,说明枇杷幼果低温冻害等级指标可应用于低温冻害预测。     

气候变化对两种候鸟物候期的影响初探——以大丰市调查为例

选取大丰市气候(1960-2007年)及两种候鸟——家燕(Hirundo rustica)(1989-2007年)和四声杜鹃(Cuculus micropterus)(1995-2007年)的物候期资料,利用一元线性回归、多元逐步回归和M-K突变检验方法,分析了大丰市气候及两种候鸟物候期的趋势变化特征及候鸟物候期对气候变化的响应关系。结果表明:(1)近48a来大丰市年平均气温上升趋势明显,倾向率为0.18℃.10a-1(P0.01),于2004-2005年发生突变性增温;年平均风速呈极显著的下降趋势(P0.01),总日照时数、累积降水量的变化趋势不明显(P0.05);(2)物候期变化趋势表现在家燕始见期、四声杜鹃始鸣期均略有提早,家燕始、绝见期间隔时间略有延长,四声杜鹃间隔期以20.2d.10a-1的速率极显著缩短;(3)影响家燕始见期、间隔期的敏感气候因子是3月平均风速,影响其绝见期的敏感气候因子是5月平均温度;影响四声杜鹃始鸣期的敏感气候因子是5月总日照时数,影响其绝鸣期的关键气候因子是年平均风速、6月平均温度及7月累积降水量,影响间隔期的关键气候因子是年平均风速、6月平均温度及7月总日照时数。说明候鸟物候期对气候变化响应比较敏感,可作为气候变化的指示器。     

Accumulation of copper in soils and leaves of tomato plants in greenhouses in Turkey

Copper (Cu)‐containing fertilizers, fungicides, and bactericides has been used extensively in the greenhouses in the Antalya province in recent decades with the use of such materials tending to increase year by year. The level of DTPA‐extractable Cu was determined in 210 soils (0–20 and 20–40 cm depth) and 105 leaf samples obtained from 105 tomato greenhouses. The DTPA‐extractable Cu contents of the soils taken from the 0–20 depth ranged between 0.76 and 88.03 mg kg^‐1 (mean 7.79 mg kg^‐1). The percentage of soils containing DTPA‐extractable Cu greater than the critical toxicity level (20 mg kg^‐1) was 8.1. The Cu content of tomato leaf samples ranged between 2.4 and 1,490 mg kg^‐1 (mean 166.5 mg kg^‐1). The Cu concentration in leaf samples was very high due to the intensive use of foliar applied Cu‐containing chemicals. As a consequence, 24.8% of the leaf tomato samples analyzed contained over 200 mg Cu kg^‐1, the maximum accepted tolerance level. Therefore, it may be necessary to reduce the use of Cu‐containing pesticides and fertilizers, or at least reduce the amount of Cu‐containing fertilizers being used in those greenhouses where Cu‐containing pesticides have been or are being used.     

Role of selenium in mitigation of cadmium toxicity in pepper grown in hydroponic condition

Selenium (Se) is an essential element for humans but is not considered as essential for plants. However, its beneficial role in improving plant growth and stress tolerances is well established. In order to study the role of Se in cadmium (Cd) toxicity in pepper (Capsicum frutescens cv. Suryankhi Cluster), this experiment was carried out in greenhouse conditions. Treatments comprised Cd [0, 0.25, and 0.5 mM cadmium chloride (CdCl₂)] and Se [0, 3, and 7 µM sodium selenite (Na₂SeO₃)] with three replications. The result showed that Cd decreased chlorophyll a, chlorophyll b, and carotenoids, whereas Se supplementation diminished Cd toxicity on photosynthetic pigment. Selenium at 7 µM significantly increased the leaf area in the plants grown at 0.25 mM Cd. The application of Se at 3 µM with 0.25 mM Cd and Se at 3 µM and Se at 7 µM with 0.5 mM Cd increased the activity of catalase (CAT). Selenium at 7 µM decreased the proline content of pepper leaves exposed to Cd at 0.5 mM (30%). Selenium significantly enhanced the antioxidant activity of leaves, which was diminished by Cd toxicity. In general, Se has a beneficial effect on plant growth and is an antioxidant enzyme of pepper cv. Suryankhi Cluster under Cd stress and non-stress conditions.     

红壤区不同肥力水稻土根际硝化作用特征

通过根际培养箱(三室)——速冻切片技术研究了红壤地区高、低两种肥力下水稻苗期根表、根际和土体土壤矿质态氮含量和硝化强度,以及水稻生长、氮素积累的差异。结果表明,肥力水平对水稻根表和根际土壤铵态氮(NH4+-N)含量无显著影响,但高肥力显著提高土体土壤NH4+-N含量,以及根表、根际和土体土壤硝态氮(NO3--N)含量及硝化强度。两种肥力水稻土硝化强度最大值均出现在距根表2 mm处,分别为0.20和0.31μmol kg-1 h-1。土体土壤硝化强度随距根表距离增加而降低,低肥力土壤在距根表10～40mm处时硝化强度接近本底值,而高肥力土壤在距根表20～40 mm处时接近本底值。与不种水稻的CK相比,种植水稻显著提高根际土壤硝化强度。高肥力能显著改善水稻生长,增加植株氮素积累量,尤其显著促进根系生长及通气组织发育。由于红壤稻田肥力水平的差异造成水稻根际硝化强度以及水稻吸收NO3-的差异,导致高肥条件下水稻显示出更强的生长势和氮素吸收利用能力。因此,合理提高红壤稻田肥力水平对改善红壤区水稻根际土壤硝化作用及水稻氮素营养具有重要意义。     

自由基在鸡肾病发生中的作用研究

肾病即急性肾小管坏死.鸡肾病在养鸡生产中极为常见,尤其近年来,鸡肾病的发生日益增多,由于其发生机制不清楚,临床治疗鸡肾病的依据不足,致使治疗效果不佳,为此,提出本研究以探讨鸡肾病的发生机制,为本病防治提供理论依据.     

Occurrence of Sexual Hormones in Sediments of Mangrove in Brazil

The presence of sexual hormones (female estrogens) was assessed in sediments of a mangrove located in the urban region of southern Brazil. The estrogens are involved in human sexual reproduction. They act as the chemical messengers, and they are classified as natural and synthetic. The estrogens inputs in the environment are from treated and untreated sewage. The presence of estrogens in sewage is excretion from the female due to natural production and use of contraceptives (synthetic estrogens). With the indiscriminate release of sewage into the environment, estrogens can be found in rivers, lakes, and even in oceans. In this work, the presence of estrone (E1), 17-??-estradiol (E2), and 17-??-ethynilestradiol (EE2) in eight sedimentary stations in Itacorubi mangrove located on Santa Catarina Island, south Brazil, was investigated. Historically, the Itacorubi mangrove has been impacted by anthropogenic activities because the mangrove is inserted in the urban area of the Florianopolis. The estrogen EE2, used as contraceptive, had the highest concentration in mangrove sediment, 129.75?±?3.89 ng/g. E2 was also found, with its concentration ranging from 0.90?±?0.03 to 39.77?±?1.19 ng/g. Following the mechanism, under aerobic or anaerobic conditions, E2 will first be oxidized to E1, which is further oxidized to unknown metabolites and finally to CO₂ and water (mineralized). EE2 is oxidized to unknown metabolites and also finally mineralized. Theoretically, under anaerobic conditions, EE2 can be reduced to E1 even in environments such as mangrove which is essentially anaerobic.     

Meta-analysis in the Selection of Groups in Varieties of Citrus

Brazil is the largest producer of oranges (Citrus sinensis) in the world. The nutrient management of tree orchards is designed from experiments with a limited number of varieties. This knowledge is transferred to other varieties by diagnosing tissue nutrient composition and tree demand. Compositional data analysis has been first applied to tissue analysis of agricultural crops using centered log ratios with compositional nutrient diagnosis (CND-clr). The isometric log ratio (ilr) transformation is a new approach based on binary nutrient ratios and the principle of orthogonality (CND-ilr). We analyzed eleven nutrients: nitrogen (N), sulfur (S), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), boron (B), copper (Cu), zinc (Zn), manganese (Mn), and iron (Fe) in leaf tissue samples across 108 commercial plots (thirty-one grow Valencia, twenty-two Hamlim, twenty Pera, and thirty-five Natal). Nutrients were partitioned between macro- and micronutrients as well as anionic and cationic species. The effect size of varieties over Valencia was quantified by the mean and standard deviation of ilr values across ilr coordinates. Specific varietal nutrient profiles and ilr norms were defined. The nutrient profile of orange varieties could be classified into homogeneous groups to take advantage of fertilizer trials conducted on varieties of the same group. The Aitchison distance and a perturbation vector could be instrumental for diagnostic purposes and nutrient management.     

Effect of iron-quercetin complex on reduction of nitrite in in vitro and in vivo systems

This study investigated whether reducing agents such as quercetin and iron(II) facilitate formation of nitric oxide (NO) gas from orally ingested nitrite in an vivo study. When 3 mg/kg Na (15)NO2 was orally administered to rats with or without iron(II) or quercetin, Hb (15)NO, which is indicative of systemic (15)NO, was detected in the blood, with the maximum blood concentration of Hb (15)NO at 15 min after nitrite or nitrite plus quercetin treatment, whereas after administration of nitrite plus iron(II) or nitrite plus iron(II) and quercetin, the time was shortened to 10 min. Interestingly, iron(II), quercetin, or iron(II) plus quercetin did not affect the total amount of Hb (15)NO generated from orally administered Na (15)NO2. However, the systemic nitrite concentration was significantly decreased in the presence of iron(II) or iron(II) plus quercetin. These results may indicate that iron(II) is critical to the generation of NO gas from nitrite, whereas quercetin contributed little under the in vivo experimental conditions.     

旱地果园水肥管理模式研究进展

分析了旱地果园水肥管理模式的研究进展和存在问题,指出水肥胁迫尤其是水钾已成为旱区果树高产稳产优质化的主要限制因子。在系统探讨旱地果园水分管理、养分管理、综合管理以及果树叶营养综合诊断施肥标准的基础上,提出了旱地果园的高效水肥管理模式。     

Role of aldehyde oxidase in the hepatic in vitro metabolism of 3-methylindole in pigs

The metabolism of 3-hydroxy-3-methylindolenine (HMI), a recently discovered metabolite of 3-methylindole (3MI, skatole) produced by porcine liver microsomes, was investigated in vitro using porcine liver cytosol. HMI was rapidly metabolized to a single product, 3-hydroxy-3-methyloxindole (HMOI), by porcine cytosol. By the use of the selective inhibitors menadione and quinacrine, it was shown that the enzyme responsible for the oxidation of HMI into HMOI was aldehyde oxidase (AO; aldehyde:oxygen oxidoreductase, EC 1.2.3.1). The activity of AO in the conversion of HMI to HMOI was measured in a population of pigs (n = 30) with a wide range of 3MI levels in back fat (0.07-0.30 mg/kg). AO activity was found to be negatively correlated (r = -0.70; P < 0.001) with the level of 3MI in fat. The results of the present study suggest that AO plays an important role in the metabolism of 3MI in the pig and that its catalytic activity is related to an adequate 3MI clearance.     

北京市郊典型农田施肥研究与分析

通过问卷调查形式,对京郊粮田、菜田和果园3种农田施肥现状进行研究.结果表明,菜田和果园化肥施用量较高,氮、磷、钾肥均显著高于粮田.菜田和果园氮肥用量分别为1741.0和1172.8 kg/hm2,分别是粮田氮肥用量的4.5和3.0倍;磷肥用量分别为1375.1和996.4 kg/hm2,分别是粮田磷肥用量的15.5倍和11.2倍;钾肥用量分别为791.3和602.4 kg/hm2,分别是粮田钾肥用量的21.1和16.1倍.另外,3种利用方式的农田氮、磷和钾肥施用比例不同,粮田为75.4%、17.3%和7.3%;果园为42.3%、36.0%和21.7%;而菜田为44.6%、35.2%和20.3%.3种种植类型中均存在氮肥投入过量、钾肥不足的问题.