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1.
单季晚稻褐飞虱发生程度的气候诊断   总被引:8,自引:2,他引:6  
应用数理统计方法 ,分析了上海地区单季晚稻褐飞虱发生程度、始见期与气候生态因子的关系。结果表明 ,上海地区单季晚稻褐飞虱始见期与当年 4月 16~ 30日的降水日数、上年 10月份 5 0 0hPa 110°~ 15 0°E平均副热带高压脊线位置间的相关系数分别为 - 0 . 6 30 7、0 . 4 871。单季晚稻褐飞虱的发生程度与当年 1月 1日~ 2月 10日平均最低气温的相关系数为 - 0 . 5 2 18,与当年 7月份降水量的相关系数为 0 . 5 2 0 3,与上年 12月份 5 0 0hPa 110°~ 15 0°E内平均副热带高压脊线位置的相关系数为- 0 5 374。当ElNino发生强度强且发生时间在春季 ,则当年上海地区单季晚稻褐飞虱发生程度为重 ;当ElNino发生强度在中等以上且发生时间在秋季 ,则次年上海地区单季晚稻褐飞虱发生程度为重。LaNina事件与上海地区单季晚稻褐飞虱发生程度的关系不明显。  相似文献   

2.
褐飞虱(Nilaparvata lugens)发生的分形性质研究   总被引:3,自引:0,他引:3  
马飞  李红兵  程遐年 《生态学报》2001,21(2):279-285
运用分形理论以安徽省庐江县植保站和江苏省吴县值保站1979~1990年及太湖地区农科所1986~1998年间褐飞虱发生的田间系统调查资料为例,对褐飞虱发生的性质进行了探讨。结果表明:(1)庐江站、吴县站和太湖地区农科所褐飞虱发生在一定标度域内具有分形性质。其分维值分别为0.7158、0.52l2和0.2816;(2)褐飞虱发生的分维值是表征一定标度区间的发生程度差异的一个新的参数,分维值大,则发生程度轻,反之则重(3)分维数D值与褐飞虱发生的聚集程度是密切相关的,D值小聚集程度大,反之聚集程度小,D值可以作为褐E虱聚集分布程度的一个指标;(4)褐飞虱发生具有多重分形结构,其广义维数谱Dq曲线可以用于褐飞虱发生的预测预报。  相似文献   

3.
为了阐明华南双季稻区早稻收割和晚稻移栽对褐飞虱种群动态的影响,2011年在韶关市采用田间调查与卵巢解剖的方法研究了双季早稻、双季晚稻、田埂杂草上褐飞虱的种群动态及虫源性质。结果表明:早稻收割后,早稻上大量的褐飞虱1~2龄若虫被淘汰,3龄以上若虫及成虫不断转移扩散致使附近晚稻秧田和杂草上褐飞虱虫量突增;晚稻移栽之后,杂草及晚稻秧田的褐飞虱又向新插秧的晚稻进行转移,但成为有效虫源的虫量较少,因此,早稻收割和晚稻移栽对褐飞虱种群动态造成了极为不利的影响,晚稻秧田和田埂杂草可作为褐飞虱转移过程中的流动栖息场所,在褐飞虱虫量转移中起着一定的作用。  相似文献   

4.
《褐飞虱研究与防治》一书 ,由陈遐年等教授主编 ,已于 2 0 0 3年 7月由中国农业出版社正式出版发行。本书全面、系统地论述了褐飞虱研究与治理领域的最新进展、研究方法和实际应用。全书分 :国内外褐飞虱研究进展、褐飞虱灾害的地理分布及其时空变化规律、褐飞虱的形态特征和稻田内近似种类的识别、褐飞虱的种群生物学特性、褐飞虱大发生的种群特征、褐飞虱大发生与稻田生物群落关系、诱发褐飞虱再猖獗的生理生态因素、褐飞虱的远距离迁飞行为及其生理生态机制、褐飞虱发生系统的混沌特性及预测预报和褐飞虱防治技术的研究与应用等 1 2章。…  相似文献   

5.
李仲惺 《昆虫知识》1998,35(2):65-67
褐飞虱Nilaparvatalugens(Stal)是浙南地区连作晚稻后期的主要害虫,在大发生年份,如1995、1996年,七(6)代褐飞虱连续在我市连作晚稻部分田块上大发生,有些田块甚至达到特大发生的程度。在一些地区,由于防治失时及农药选择不当等原因,导致水稻毁秆倒伏,造成严重损失。为此,本文就1995与1996年两年的田间调查结果,分析其原因,对防治对策进行讨论。1大发生的原因1.1有利的气象因子有利的气象因子是诱发七(6)代褐飞虱大发生的一个重要原因。1995年9月下旬旬平均气温23.2℃,比1994年同期的22.3℃高出0.9℃;降雨量73.6mm…  相似文献   

6.
2007-2012 年佛冈县稻飞虱灯下发生期及种群数量动态分析   总被引:1,自引:0,他引:1  
明确佛冈县稻飞虱灯下发生期及灯诱种群数量动态,对当地稻飞虱的预测预报和防治工作具有重要意义.根据佛冈县2007-2012年白背飞虱和褐飞虱的灯诱数据,分析了该县白背飞虱和褐飞虱的灯下始见日、终见日、发生期及灯诱量等.结果表明在佛冈地区,白背飞虱和褐飞虱混合发生;白背飞虱的灯下始见日集中在3月底至4月上旬,明显比褐飞虱早一个月,终见日均在10月下旬,差别不大;稻飞虱在早稻和晚稻期间均会出现大小不一的灯诱高峰,早稻期间白背飞虱高峰期集中在5月中旬至6月中旬,褐飞虱灯诱高峰期较迟,主要在7月中旬前后;晚稻期间向背飞虱高峰期大多在9月上旬至10月上旬,褐飞虱高峰期在10月份;早稻期间,白背飞虱的灯诱量占绝对优势,晚稻期间褐飞虱的灯诱量上升,与白背飞虱灯诱量基本持平.因此,佛冈县稻飞虱的灯下发生期及种群数量动态在一定程度上可反映当地稻飞虱的发生情况.  相似文献   

7.
近30多年来,气候变化对中国褐飞虱的灾变性迁入带来了明显的影响,为了进一步了解虫源地的异常气候变化对我国褐飞虱迁入量的影响,利用1980—2016年中国各植保站提供的褐飞虱虫情资料及同期美国国家环境预测中心(NCEP)提供的全球气象再分析资料,分析了中国褐飞虱境外主要虫源地中南半岛前期异常气候条件对中国南方稻区褐飞虱发生程度的影响,并对褐飞虱发生等级与影响其迁飞的气象因子进行了相关性分析,筛选出关键预报因子,分别应用支持向量机(SVM)、BP神经网络和多元回归分析3种方法对代表站点褐飞虱年发生等级进行了预测,并比较了3种预测模型的优劣。结果表明:(1)中南半岛气候异常区主要分布在北部,异常气候的发生次数在中南半岛呈现出北高南低的特征,并从北向南呈环状递减。(2)中南半岛前期温度偏高(暖冬、暖春)、相对湿度偏大(湿冬、湿春),易引起褐飞虱在中国南方稻区的偏重以上发生;若中南半岛前期气候偏冷(冷冬、冷春)、偏干(干冬、干春),则常导致褐飞虱在中国南方稻区的偏轻以下发生。(3)通过比较3种模型的历史回代率和预测准确率,发现3种模型对褐飞虱的发生程度均有一定的预测能力,其中SVM模型的预测效果最好,BP神经网络次之,多元线性回归模型最差,表明SVM更加适用于生产实际中的褐飞虱发生程度预测。  相似文献   

8.
马飞  丁宗泽  沈龙元  程遐年 《生态学报》2001,21(9):1542-1558
利用我国长江流域的吴县1979-1990年及太湖地区农科所1986-1998年6-11月份褐飞虱田间发生时间序列资料,将褐飞虱发生的一维时间序列拓展到多维相空间中去,研究结果表明:(1)我国长江流域短期褐飞虱发生演化,在相空间中存在吸引子,并具有分维结构,其维数分别是1.6和0.68,为混沌吸引子(或奇异吸子);(2)就我国长江流域褐飞虱发生的短期变化而言,为了能在维相空间支撑上述奇怪吸引了,最好选取4个变量或建立最低为4阶的动力学模型式来进行描述。  相似文献   

9.
应用单克隆抗体评价拟环纹豹蛛对褐飞虱的控制作用   总被引:2,自引:0,他引:2  
应用褐飞虱的单克隆抗体 4 B8研究了 1999年浙江大学华家池校区农场汕优 6 3单季晚稻田中拟环纹豹蛛对褐飞虱的捕食作用。采用盘拍法的调查结果表明 ,褐飞虱、拟环纹豹蛛种群数量高峰期均在水稻生长后期 (9月中旬 ) ,最大种群密度分别为12 6头 /丛和 1.83头 /丛。对每次捕获的每头拟环纹豹蛛样品的抗体夹心 EL ISA检测结果表明 ,拟环纹豹蛛对褐飞虱单克隆抗体的阳性反应率与田间褐飞虱的生物量及拟环纹豹蛛对褐飞虱的占有量显著相关。定量评估结果表明 ,在此密度条件下 ,拟环纹豹蛛对褐飞虱的最大捕食率仅为 2 .2 8%。拟环纹豹蛛对褐飞虱的平均捕食量、总捕食量和捕食率与田间褐飞虱的生物量显著相关。总捕食量、捕食率与拟环纹豹蛛种群密度极显著相关  相似文献   

10.
包云轩  蒋蓉  谢晓金  朱叶芹  杨荣明  朱凤 《生态学报》2014,34(23):7078-7092
近30年来,中国褐飞虱的灾变性迁入因受气候变化的影响而出现了明显的时空变异,为了揭示气候异常对褐飞虱区域性灾变的影响,为我国褐飞虱灾变预警及其区域危害的防控提供理论依据,在收集1983—2008年江苏省32个植保站褐飞虱灯诱资料、1981—2008年太平洋海表温度和南方涛动指数数据及1983—2008年江苏省70个气象台站降水和气温观测资料的基础上,选取高邮、通州和宜兴作为江苏省不同水稻生长区的代表性测站(其中高邮代表江淮稻区,通州代表苏北沿海稻区,宜兴代表苏南稻区),通过对近30年来太平洋海温场、南方涛动、迁入区降水和温度异常与江苏省褐飞虱发生程度之间关系的分析,探讨了气候异常对该省褐飞虱灾变性迁入的影响。结果表明:(1)赤道东太平洋海表水温持续偏高的厄尔尼诺事件多引发江苏省褐飞虱偏重以上程度的发生,且其首次迁入峰的出现时间与厄尔尼诺事件开始期之间有1—14个月的滞后期。(2)南方涛动指数(SOI)持续出现负值的厄尔尼诺事件发生的当年或次年,褐飞虱为偏重以上的发生程度,且其首次迁入峰的出现时间滞后于SOI负值开始期1—14个月。(3)登陆并影响江苏的强热带气旋偏多的拉尼娜年也会出现褐飞虱偏重以上的发生。(4)降水对褐飞虱迁入的影响明显,但有限制条件;降水量大、降水日数多的年份褐飞虱迁入量大、发生程度重;以6—10月降水量、降水日数和降水强度为预报因子,建立了褐飞虱发生等级的回归方程,方程拟合和试报效果好。(5)夏秋季6—10月地面气温的异常对江苏省褐飞虱迁入的发生有一定的影响,秋温偏高的年份常导致江苏省褐飞虱偏重以上的发生。  相似文献   

11.
Summary

The comparative depressive actions of the three barbiturates, barbital, amobarbital, and secobarbital, respectively classed as long-, medium-, and short-acting barbiturates, on potassium and chloride ion uptake by intact barley and rice seedlings were investigated. Barbital exerted the least and secobarbital the most depressive action on the uptake of both potassium and chloride ions by both types of seedlings. The functioning of the Meyer-Overton principle regarding lipid solubility in relation to drug or anaesthetic potency, observed previously in germinating angiosperm seedlings and in germinating pollen grains, was also evident in this investigation.  相似文献   

12.
Indocyanine green (ICG) is a photosensitive reagent with clinically relevant diagnostic and therapeutic applications. Recently, ICG has been investigated for its utility as an exogenous chromophore during laser-induced heating. However, ICG's effectiveness remains hindered by its molecular instability, rapid circulation kinetics, and nonspecific systemic distribution. To overcome these limitations, we have encapsulated ICG within dextran-coated mesocapsules (MCs). Our objective in this study was to explore the ability of MCs to induce thermal damage in response to laser irradiation. To simulate tumorous tissue targeted with MCs, cylindrical phantoms were prepared consisting of gelatin, intralipid emulsion, and various concentrations of MCs. The phantoms were embedded within fresh chicken breast tissue representing surrounding normal tissue. The tissue models were irradiated at lambda = 808 nm for 10 min at constant power (P = 4.2 W). Five hypodermic thermocouples were used to record the temperature at various depths below the tissue surface and transverse distances from the laser beam central axis during irradiation. Temperature profiles were processed to remove the baseline temperature and influence of light absorption by the thermocouple and subsequently used to calculate a damage index based on the Arrhenius damage integral. Tissue models containing MCs experienced a maximum temperature change of 18.5 degrees C. Damage index calculations showed that the heat generation from MCs at these parameters is sufficient to induce thermal damage, while no damage was predicted in the absence of MCs. ICG maintains its heat-generating capabilities in response to NIR laser irradiation when encapsulated within MCs. Such encapsulation provides a potentially useful methodology for laser-induced therapeutic strategies.  相似文献   

13.
A simple experimental system is described whereby the comparative actions of long-, medium-, and short-acting barbiturates can be demonstrated in a relatively short period of time under optical microscopy using pollen grains as the biological test or assay system. This experimental system yields results which are both readily obtainable and consistently reproducible. In addition, the Meyer—Overton principle regarding lipid solubility in relation to drug or anaesthetic potency in animals and in humans is demonstrable in this experimental system which employs a haploid microscopic plant material.  相似文献   

14.
Mid-infrared spectroscopy (MIR) is used to predict fatty acid (FA) composition of individual milk samples (n=267) of Brown Swiss cows. FAs were analyzed by gas chromatography as a reference method. Samples were scanned (4000 to 900 cm-1) by MIR, and predictive models were developed using modified partial least squares regressions with full cross-validation. The methods using a first derivative or multiplicative scatter corrected plus first derivative resulted, on average, in the best predictions. Coefficients of correlation between measured and predicted C8:0, C10:0, C12:0, C14:0, anteiso-C17:0, c9-C18:1, and medium- and long-chain FA, and saturated, monounsaturated and unsaturated FA ranged from 0.71 to 0.77, suggesting that prediction models can be implemented in milk recording schemes to routinely collect information on FA composition from the whole Brown Swiss population for breeding purposes.  相似文献   

15.
Freeze-thawed rat liver mitochondria were extensively washed with potassium phosphate, pH 7.5, and the residue was extracted with 10 mM potassium phosphate, pH 7.5, 1% (w/v) sodium cholate, 0.5 M KCl. The four beta-oxidation enzyme activities of the washes and the last extract were assayed with substrates of various carbon chain lengths. Our data suggest that the last extract contains a novel acyl-CoA dehydrogenase and long-chain 3-hydroxyacyl-CoA dehydrogenase. A novel acyl-CoA dehydrogenase was purified. The molecular masses of the native enzyme and the subunit were estimated to be 150 and 71 kDa, respectively. One mole of enzyme contained 2 mole of FAD. These properties and immunochemical properties of the enzyme differed from those of three other acyl-CoA dehydrogenases: short-, medium-, and long-chain acyl-CoA dehydrogenases. Carbon chain length specificity of the enzyme differed from that of other acyl-CoA dehydrogenases. The enzyme was active toward CoA esters of long- and very-long-chain fatty acids, but not toward those of medium- and short-chain fatty acids. The specific enzyme activity was greater than 10 times that of long-chain acyl-CoA dehydrogenase when palmitoyl-CoA was used as substrate. We propose the name "very-long-chain acyl-CoA dehydrogenase" for this enzyme.  相似文献   

16.
17.
The purpose of this study was to examine whether prediction of antagonist moment (M(flx)) of the hamstrings using clinically applicable models depends on the muscles examined. Nine healthy males performed maximal isometric knee extension and flexion contractions at 0 degrees , 45 degrees and 90 degrees angles. Calibration knee flexion efforts were also performed at different levels of intensity. The resulting electromyographic (EMG) - moment curves were fitted using polynomial equations which were then used to estimate M(flx) from the antagonist EMG. Analysis of variance designs showed that the M(flx) predicted using the biceps femoris EMG was not significantly different compared with those predicted using the semitendinosus EMG data (p>0.05). Further, prediction of M(flx) using the EMG of both muscles or a combination of EMGs and architectural properties reduced estimation error but did not provide significantly different predicted values compared with the simpler single-muscle EMG - moment models (p<0.05). It appears that M(flx) prediction using the present EMG - moment model is not muscle specific. Prediction using models which combine EMG data and anatomic parameters of the hamstring muscle components yielded more accurate estimates and therefore their use to examine co-contraction levels is recommended.  相似文献   

18.
Planning of the control of Plasmodium falciparum malaria leads to a need for models of malaria epidemiology that provide realistic quantitative prediction of likely epidemiological outcomes of a wide range of control strategies. Predictions of the effects of control often ignore medium- and long-term dynamics. The complexities of the Plasmodium life-cycle, and of within-host dynamics, limit the applicability of conventional deterministic malaria models. We use individual-based stochastic simulations of malaria epidemiology to predict the impacts of interventions on infection, morbidity, mortality, health services use and costs. Individual infections are simulated by stochastic series of parasite densities, and naturally acquired immunity acts by reducing densities. Morbidity and mortality risks, and infectiousness to vectors, depend on parasite densities. The simulated infections are nested within simulations of individuals in human populations, and linked to models of interventions and health systems. We use numerous field datasets to optimise parameter estimates. By using a volunteer computing system we obtain the enormous computational power required for model fitting, sensitivity analysis, and exploration of many different intervention strategies. The project thus provides a general platform for comparing, fitting, and evaluating different model structures, and for quantitative prediction of effects of different interventions and integrated control programmes.  相似文献   

19.
玉米低温冷害动态评估和预测方法   总被引:22,自引:1,他引:21  
马树庆  刘玉英  王琪 《应用生态学报》2006,17(10):1905-1910
为了防御和减轻玉米低温冷害,应用改进的玉米生长发育和干物质积累动态模型,采用新的玉米低温冷害指标和参数,建立了玉米低温冷害发生及损失程度的动态预测和评估方法.该方法遵循积温学说和玉米生物学、生态学原理,用相对积温作为发育期预报和灾害判别的主导因子,用干物质亏缺率代表冷害减产率.经代表地区不同气候年型的验证和试用,证明该冷害预报和评估方法具有较好的客观性和适用性,经过参数和指标调整后,可应用于东北地区各地.  相似文献   

20.
Conflicts between humans and wildlife, especially wild boar (Sus scrofa), have caused serious problems across the world in recent years. It is necessary to effectively control wild boar agricultural damage that may be influenced by many factors. In this study, we collected data on agricultural damage caused by wild boars from November 2009 to October 2010 using field surveys and social interviews in Taohongling National Nature Reserve of Jiangxi Province, China. We constructed models using binary logistic regression analysis to predict damage risks and to identify the factors influencing damage risks. About 8.1 % of croplands were damaged by wild boars, and the damage to rice, cotton, and other crops were not distributed based on their respective availability as shown by the result of a chi-square goodness-of-fit test. Five factors (Japanese silvergrass, soil conditions, terrain, distances to settlements, and water sources) were explained in a model based on damage area (area-based model) with the prediction accuracy being 72.1 %. In addition to these five factors, one additional factor (i.e. distance to forest edge) was retained in a model based on damage frequency (frequency-based model) with the prediction accuracy being 83.1 %. Caution is needed when we apply these two models to predict boar damage to crops, and it is recommended that both models be used in combination to predict the damage probabilities more accurately.  相似文献   

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