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1.
杀虫植物中的次生物质在IPM中的作用   总被引:5,自引:0,他引:5  
就杀虫植物中次生物质种类、分布、活性、利用以及它们在害虫综合治理(IPM)中的作用等方面进行了论述。  相似文献   

2.
不同光源对棉铃虫蛾趋光率的影响   总被引:2,自引:0,他引:2  
为进一步探讨棉铃虫蛾的趋光行为和在害虫综合治理中更好地利用诱虫灯,本试验采用室内行为试验的方法研究了不同光源对棉铃虫蛾趋光率的影响。结果显示:光源、光期和暗期、羽化日龄对棉铃虫蛾的趋光率有一定影响。其中,双波灯和黑光灯照射下的趋光率比蓝光灯、绿光灯、黄光灯、红光灯、日光灯照射下的高,并且差异显著(P<0.05);暗期趋光率显著高于光期趋光率;1、3、5、7日龄蛾中,以3日龄蛾的趋光率高。  相似文献   

3.
Lustick S  Adam M  Hinko A 《Science (New York, N.Y.)》1980,208(4447):1052-1053
The effect of the angle of incidence on the radiative heat load was determined for light and dark plumage. As the angle of incidence to the solar radiation source increases the difference in heat transfer between light and dark plumage disappears. Thus, by postural adjustment, a dark bird may become thermally white with regard to the radiative heat load.  相似文献   

4.
[目的]为了探究桥梁与路基(桥路)过渡段和路基附近流场、水平风速和积沙特征的分布规律,揭示桥路过渡段沙害形成机理.[方法]通过数值模拟的技术手段对不同来流风速下桥路过渡段和路基附近的流场变化和积沙特征进行研究,并将数值模拟的积沙分布情况与现场实际积沙情况对比,验证数值模拟结果的准确性.[结果]当风沙流运动到桥路过渡段时...  相似文献   

5.
Light-enhanced potassium absorption by corn leaf tissue   总被引:8,自引:0,他引:8  
D W Rains 《Science (New York, N.Y.)》1967,156(780):1382-1383
The rate of absorption of potassium by slices of corn leaf in the light was about twice the rate in the dark. When the light was turned on or off, changes in the rate of absorption took place some minutes after the change in illumination. Experiments with the antimetabolites, 2,4-dinitrophenol and cyanide, indicated that the source of energy for active accumulation of potassium by green tissue in the light was different from that in the dark. In the light, energy was closely linked to photosynthetic reactions; in the dark, it was linked to respiratory processes.  相似文献   

6.
贵州省荔波县岩溶洞穴多,洞穴动物丰富,具有重要的科研价值。在洞穴生态系统中,洞穴动物是重要的生物类群,为探讨洞穴动物群落结构及其与环境的关系。本研究对荔波的干细洞(未受人类干扰)和拉梭洞(已受人类干扰)的洞穴动物进行了调查,并比较了两个洞穴的动物群落结构特征,应用主成分(PCA)法分析了动物群落结构与环境因子的关系。结果表明:干细洞共获动物536号,计56种,拉梭洞共获动物363号,计23种。多样性指数、丰富度指数、均匀度指数、优势度指数最高的分别是干细洞有光带群落(2.748 6)、干细洞有光带群落(6.733 8)、干细洞黑暗带群落(0.841 9)、拉梭洞黑暗带群落(0.395 5);群落多样性指数和丰富度指数均沿有光带、弱光带、黑暗带呈递减趋势。群落间相似性指数偏低,除了群落E-F(0.428 5)、群落C-F(0.272 7)处于中等不相似水平,其余群落之间均处于极不相似水平。PCA分析表明,影响干细洞动物群落结构的主导因子为土壤营养元素(Na、K)、土壤有机质、气温、空气湿度和土壤湿度,影响拉梭洞动物群落结构的主导因子为土壤营养元素(Na、K)、土壤有机质、空气湿度、CO2含量和滴水pH。研究可为洞穴动物的保护、生态资源可持续发展提供科学依据。  相似文献   

7.
The master circadian oscillator in the hypothalamic suprachiasmatic nucleus is entrained to the day/night cycle by retinal photoreceptors. Melanopsin (Opn4), an opsin-based photopigment, is a primary candidate for photoreceptor-mediated entrainment. To investigate the functional role of melanopsin in light resetting of the oscillator, we generated melanopsin-null mice (Opn4-/-). These mice entrain to a light/dark cycle and do not exhibit any overt defect in circadian activity rhythms under constant darkness. However, they display severely attenuated phase resetting in response to brief pulses of monochromatic light, highlighting the critical role of melanopsin in circadian photoentrainment in mammals.  相似文献   

8.
对巴丹吉林沙漠东南缘民勤西沙窝荒漠绿洲过渡带不同立地条件下沙蒿光合特性进行了研究。结果表明,5种立地类型土壤含水率最大值均为20~40 cm土层,0~60 cm各土层土壤水分含量及总含水率变化趋势均为丘间低地>平缓沙地>流动沙丘>半固定沙丘>固定沙丘;5种立地类型中沙蒿总叶绿素含量及叶绿素荧光参数变化与水分变化特征均一致;各立地类型中叶片快速光响应曲线中有效量子产量、PSⅡ光化学淬灭系数(qP)均随光强升高而减小,而叶片非光化学淬灭系数NPQ和电子传递速率ETR均随光强升高而增加,中低光强时差异较小,随光强升高差异性逐渐增大,总体表现为丘间低地ETR最大,流动沙丘、平缓沙地及半固定沙丘次之,固定沙丘最小。由此说明,丘间低地上生长的沙蒿具有较强的抗光抑制能力,可产生较高的光化学效率,是最适宜于沙蒿生长的立地类型。  相似文献   

9.
Wang H  Ma LG  Li JM  Zhao HY  Deng XW 《Science (New York, N.Y.)》2001,294(5540):154-158
Arabidopsis seedling photomorphogenesis involves two antagonistically acting components, COP1 and HY5. COP1 specifically targets HY5 for degradation via the 26S proteasome in the dark through their direct physical interaction. Little is known regarding how light signals perceived by photoreceptors are transduced to regulate COP1. Arabidopsis has two related cryptochromes (cry1 and cry2) mediating various blue/ultraviolet-A light responses. Here we show that both photoactivated cryptochromes repress COP1 activity through a direct protein-protein contact and that this direct regulation is primarily responsible for the cryptochrome-mediated blue light regulation of seedling photomorphogenic development and genome expression profile.  相似文献   

10.
The external morphology of the compound eye of the winged female and male Solenopsis invicta Buren and its microstructure in light and dark adaptations were observed using scanning electron microscopy and optical microscopy. The results indicated that the compound eye located on the lateral side of its head, is the a shape of a half ellipsoid and composed of approximately 510 ommatidia in the female, and a near hemisphere with about 805 ommatidia in the male. The ommatidium was made of a corneal lens, crystalline cone, 8 to 9 retinula cells and basement membrane. The cornea was a colorless, transparent and double convex lens. The crystalline cone, with an inverted cone shape, was approximately 14.50m long, formed by four equal parts, and surrounded by many pigment granules. The rhabdom beneath the crystalline cone, was about 75.00m long, with a thicker middle part and thinner ends. More pigment granules were scattered in the distal and proximal ends and less in the middle, and the basement membrane was on the most bottom area of the ommatidium. The primary pigment cells moved horizontally along the crystalline cone from its distal to proximal end during dark adaptation or moved reversely during light adaptation. There was no significant difference between the pigment granule distribution and the structure of the crystalline cone between female and male ommatidium under the same light or dark adaptation. It is concluded that the fire ant compound eye is an apposition eye, whose light-tuning mechanism is accomplished by the change of crystalline cone and the movement of the pigment cells.  相似文献   

11.
信息素在害虫综合治理中的研究进展   总被引:1,自引:0,他引:1  
信息素主要以化学手段研究生态系统中信息物质的产生、转运、传导、接受及作用机理,是当前国际化学生态学界最活跃的研究领域之一。本文综述了目前国内外化学生态学领域中信息素在害虫防治中的应用研究进展,及利用昆虫性信息素、聚集信息素和植物利己素、互利素等进行害虫综合治理的应用研究现状。同时展示了化学信息素在未来害虫综合治理中的应用前景及化学信息素的研究方向。  相似文献   

12.
王伟 《安徽农学通报》2010,16(18):131-132,157
在GIS技术支持下,利用研究区1996年与2009年的2期遥感影像数据,采用土地利用动态度模型、土地利用程度综合指数模型和土地利用转移矩阵对托克逊县近13a土地利用动态特征进行定量分析,总结出托克逊县近13a土地利用变化的特点及原因,提出托克逊县合理用地的对策。  相似文献   

13.
14.
Optical properties of biological tissue are variable due to the changes of micro-structures and scattering constituents after hyperosmotic chemical agents permeates into tissue.The changes of optical properties of biological tissue are due to the refractive indices matching between the scatterers with high refractive index and the ground substances,which reduce scattering of tissue.The main reasons are that permeated semipermeable chemical agents with higher refractive index than the ground substances of tissue makes the refractive index of ground substances of tissue higher by the enhancement of the permeated concentration.We studied on the collimated transmittance changes of light penetrating biological tissue after the hyperosmotic chemical agents administrates with different concentration.  相似文献   

15.
范莉  倪静 《安徽农业科学》2008,36(12):4996-4998
[目的]了解温度、湿度、光照对中草药免疫增强剂稳定性的影响。[方法]用索氏提取器提取免疫增强剂的主要成分,将提取液分别放置于-15、60℃的75%±5%、90%±5%的湿度环境中(、4 000±1 000)lx强光照射下,分别于第5、第10天进行取样分析,观察颜色变化、测pH值及其在220~400 nm的吸光度曲线,应用分光光度法分析了中草药免疫增强剂在低温、高温、高湿、强光照射的条件下处理后其化学和物理性质的变化。[结果]免疫增强剂提取液中的主要成分(生物碱、甙类、多糖)在低温、高温、高湿条件下没有明显变化。在强光照射条件下提取液颜色变淡,pH值降低。[结论]免疫增强剂提取液在低温、高温、高湿条件下比较稳定,但应避光保存。  相似文献   

16.
非瞬时或突变的马尔可夫链的一种应用方法   总被引:2,自引:1,他引:1  
介绍对于一种非瞬时或突变的状态转移过程.采用Bayes方法修订马尔可夫过程的状态转移概率矩阵;将先验概率分布修订为后验概率分布;对整个过程的信息加以吸收,得出能够反映整个过程的状态转移概率矩阵,从而达到预测目的.由此还得出一个重要结论:吸收信息的无序性.  相似文献   

17.
 蚕豆幼苗在光照条件下所吸收的磷素营养明显大于黑暗条件,并随时间延长差异增大。在黑暗处理后,即使再让阳光照射植株,其对磷素营养的吸收也下降。并且两组的叶、茎、根及整株差异都为显著。磷素在蚕豆植株中的分配为根>茎>叶。光照组叶片吸收的32P量占全株的百分数大于黑暗组,两组叶片的吸收量差异显著。  相似文献   

18.
Structural transformation between a dense molecular fluid and a polymeric liquid of phosphorus that occurred at about 1 gigapascal and 1000 degrees C was investigated by in situ x-ray radiography. When the low-pressure fluid was compressed, dark and round objects appeared in the radiograph. X-ray diffraction measurements confirmed that these objects were the highpressure liquid. The drops grew and eventually filled the sample space. Decompressing caused the reverse process. The macroscopic phase separation supported the existence of a first-order phase transition between two stable disordered phases besides the liquid-gas transition. X-ray absorption measurements revealed that the change in density at the transition corresponds to about 40% of the density of the high-pressure liquid.  相似文献   

19.
为探究斑马鱼在不同光照条件下的趋光行为差异,记录了六月龄的斑马鱼成鱼在紫外光(ultraviolet, UV)和可见光照射下的行为反应和在无光、紫光(420 nm)、蓝光(460 nm)、绿光(500 nm)、黄光(585 nm)和红光(620 nm)六种光照条件下的趋光分布情况。结果表明,刺激光为UV时,斑马鱼优先游向黑暗环境一侧,刺激光为可见光时,斑马鱼优先游向可见光一侧;UV和可见光分别设置在试验区A和试验区B时,随着UV刺激强度增加,斑马鱼的偏好指数未呈现明显的增加趋势,UV和可见光同时设置在试验区B时,随着UV刺激强度增加,斑马鱼的偏好指数呈现出明显的下降趋势;5 min和30 min时斑马鱼的平均分布率均呈现红光区>紫光区>蓝光区>黄光区,绿光区的平均分布率在5 min时高于红光区,在30 min时介于紫光区和蓝光区之间。研究表明,斑马鱼趋向可见光而远离紫外光,表现出明显的避UV性和趋可见光性,且避UV性与趋可见光性之间存在显著的拮抗作用,而无协同作用。此外,斑马鱼对红光、绿光和紫光的喜好程度较高,对黄光的喜好程度较低。研究结果可为斑马鱼视觉生态的研究提供参考。  相似文献   

20.
UV-B(280nm~320nm)、UV-A(320nm~390nm)和蓝光(390nm-500nm)经不同光受体和信号传递途径控制植物发育的各个方面。已知的蓝光/UV-A受体有隐花色素CRY1和CRY2,向光性受体有趋光素。氧化还原过程在隐花色素和趋光素信号转导过程中起重要作用。专一的UV-B光受体尚未被鉴定出,存在许多可能的UV-B信号传递途径.拟南芥查尔酮合成酶(CHS)的紫外光和蓝光转录调控成为研究热点。光受体突变体实验表明存在不同的UV-A/蓝光和UV-B光感知系统调控CHS的表达。拟南芥细胞悬浮培养物实验表明UV-B和CRY1信号传递途径在动力学上和药理学上不同。影响诱导CHS转录的启动子元件和转录因子现已被鉴定出。UV-B、隐花色素和光敏色素信号传递途径之间的相互作用调控CHS表达。UV-B途径与UV-A/蓝光途径的协同相互作用使CHS最大量表达。另外,专一的光敏色素经不同的增强和相巨作用正调控CRY1途径,负调控UV-B途径。  相似文献   

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