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81.
利用菏泽市1981~2010年各县区月、年降水资料,对厄尔尼诺年及其次年降水的特征与旱涝灾情进行分析,结果表明,菏泽市年降水量,El Nino年普遍偏少,El Nino次年普遍偏多;不同年份的El Nino事件对菏泽市降水影响不同,1997、2002年强El Nino事件造成年降水量异常偏少;在El Nino次年中1984、1993、2003年年降水量异常偏多;由于受1987年跨年度El Nino事件影响,1988年年降水量异常偏少;四季降水中,El Nino年的春季无异常;夏、秋、冬季降水普遍偏少,3个季节的30年极小值均出现在El Nino年;El Nino次年四季降水均偏多,春、夏、秋季较明显。El Nino年多旱灾,其次年多涝灾。 相似文献
82.
将健康围产期奶牛30头随机分为3组,分别于产前28 d开始饲喂NRC标准日粮(能量摄入100%组或Ⅰ组)、NRC标准增加20%日粮(能量摄入120%组或Ⅱ组)和NRC标准减少20%日粮(能量摄入80%组或Ⅲ组),产后各组奶牛均饲喂标准日粮,至产后56 d结束,观察干奶期不同能量摄入水平对围产期健康奶牛血清总胆红素、蛋白及转氨酶的影响。结果表明,围产期是机体生理状况处于剧烈变动的时期,奶牛产后的蛋白代谢活动、转氨酶活性较产前明显增强,但健康奶牛均能通过调整糖代谢、脂代谢和蛋白质代谢,促进能量与营养物质间的相互转化,适应机体的各种生理变化。 相似文献
83.
Martínez-Silvestre A Marco I Rodriguez-Dominguez MA Lavín S Cuenca R 《Research in veterinary science》2005,78(2):127-134
The object of this study was to examine the erythrocytes, leukocytes and thrombocytes of the giant lizard of El Hierro (Gallotia simonyi) by light and electron (TEM) microscopy, and cytochemical staining. Smears were prepared from blood from the ventral coccygeal vein of 10 healthy adult lizards (five males and five females) from the Giant Lizard of El Hierro Reproduction and Research Centre, Canary Islands, Spain. The cytochemical stains used were: benzidine peroxidase (BP), chloroacetate esterase (CAE), alpha-naphthyl acetate esterase (ANAE), acid phosphatase (AP), periodic acid-Schiff (PAS), toluidine blue (TB) and May-Grünwald-Giemsa (MGG). Electron microscopy was also performed on all samples. Heterophils had granules that were heterogeneous in both size and electron density, and stained with BP, PAS and ANAE. Eosinophil granules were homogeneously electron-dense and stained for AP, CAE and ANAE. Basophils had both highly and moderately electron-dense granules, and stained with TB and ANAE. Azurophil granules were of low electron-density and stained for AP, CAE and ANAE. Azurophil cytoplasm was vacuolated on TEM. The cytoplasm of lymphocytes contained many ribosomes and was positive for AP. Monocytes had a large nucleus and a vacuolated cytoplasm but did not stain by any of the cytochemical methods used. Thrombocytes had a relatively large nucleus but little cytoplasm; they did not stain cytochemically. The blood cells of the giant lizards of El Hierro differ from those of other members of the Order Squamata both morphologically and cytochemically. The variation in cytochemical responses in the blood of reptiles makes it necessary to study species individually if meaningful clinical decisions are to be made. 相似文献
84.
培养料C/N和含N量对毛木耳生长发育的影响 总被引:3,自引:1,他引:2
试验结果表明,商业化栽培毛木耳的培养料不需添加有机氮源,采用高C/N(60~100:1)和低含N量(0.4%~0.8%)的配方,干耳生物学效率(ABE%)为20%~24%,出耳后污染少,耳片商品率高。干耳产量(y_1=ABE%)、单袋经济效益(y_2,元/袋)、培养料C/N(x_1)及N%(x_2)的回归方程分别为: y_1=-15.1746 20.4322 lgx_1,r=0.9630,P>0.01; y_2=-3.5729 2.8329 lgx_1,r=0.9815,P>0.01; y_1=20.9942-20.7741 lgx_2,r=-0.9474,P>0.01; y_2=1.4202-2.4361 lgx_2,r=-0.8061,P>0.05。 相似文献
85.
In southwestern North America, large-scale climate patterns appear to exert control on moisture availability, fire occurrence, and tree demography, raising the compelling possibility of regional synchronization of forest dynamics. Such regional signals may be obscured, however, by local, site-specific factors, such as disturbance history and land use. Contiguous sites with similar physical environments, lower and middle Rhyolite Canyon, Arizona, USA, shared nearly the same fire history from 1660-1801, but then diverged. For the next 50 years, fires continued to occur frequently in lower Rhyolite, but, probably as result of flood-induced debris deposition, largely ceased in middle Rhyolite. We related stand dynamics of Arizona pine (Pinus arizonica) to fire history and drought severity and compared the dynamics in the two sites before and after the divergence in fire frequency. Fires occurred during unusually dry years, and possibly following unusually moist years. Arizona pine exhibited three age structure peaks: two (1810–1830 and 1870–1900) shared by the two sites and one (1610–1640) only in middle Rhyolite. The latter two peaks occurred during periods of unusually low fire frequency, suggesting that fire-induced mortality shapes age structure. Evidence was mixed for the role of favorable moisture availability in age structure. As expected, moisture availability had a prominent positive effect on radial growth, but the effect of fire was largely neutral. The two sites differed only moderately in stand dynamics during the period of divergence, exhibiting subtle age structure contrasts and, in middle Rhyolite only, reduced growth during a 50-year fire hiatus followed by fire-induced release. These results suggest that, despite local differences in disturbance history, forest responses to regional fire and climate processes can persist. 相似文献
86.
文章分析了内蒙古自治区黄河流域及京津周围地区生态环境现状 ,认为水土流失、土地荒漠化、草原退化是这一区域生态环境恶化的主要原因。有林地面积少 ,森林覆盖率低 ,自然灾害严重 ,生态建设投入严重不足是这一区域生态环境存在的主要问题。从抓住西部大开发机遇 ,加快我区经济发展 ,使农牧民脱贫致富等几个关键问题上论述了这一区域林业生态环境建设的必要性。 相似文献
87.
Bayoud, caused by the soilborne fungusFusarium oxysporum f.sp.albedinis (FOA), is the most serious disease of date palm. Since the disease is located in the North African countries of Morocco and
Algeria, and advancing steadily eastwards, the ultimate goal is to prevent spread of the pathogen to other date-growing areas
in the region and farther afield. Molecular diagnostic techniques have been developed for detection of FOA. In view of the
fact that the fungus does not exist in Israel, DNA of FOA was obtained to determine the reliability of these methods for diagnostic
purposes. Random amplified polymorphic DNA was not reliable enough for differentiation between FOA and various pathogenic
and saprophyticFusarium isolates. However, the polymerase chain reaction utilizing FOA-specific primers was accurate and enabled amplification of
a unique band specific to FOA DNA alone, and not that of the other tested pathogenic and saprophyticFusaria. The availability of a rapid and reliable diagnostic tool for detection of FOA will enable the Plant Protection and Inspection
Services of the Israel Ministry of Agriculture to test date palm tissue for the presence of the pathogen.
Contribution no. 513/00 from the Inst. of Plant Protection, ARO, The Volcani Center, Bet Dagan, Israel. 相似文献
88.
SDS-PAGE电泳分析显示,经过不同浓度梯度的IPTG诱导,获得了带有重组质粒pET32a-c(+)/HmH-SP70的大肠杆菌产生可溶性重组蛋白的最佳诱导条件。当IPTG的终浓度为0.15mmol/L时,诱导可溶性重组蛋白的量最高,重组蛋白浓度为22.5mg/ml。同时SDS-PAGE显示得到蛋白分子量约为90KDa的融合蛋白。并对诱导过程中产生的包涵体进行了变性和透析复性,使其变为可溶性蛋白;通过镍亲和层析的纯化以及肠激酶的酶切作用,最终得到纯度较高的HmHSP70,纯化后的目的蛋白分子质量约为70KDa,与预期结果吻合。 相似文献
89.
The Luquillo Experimental Forest (LEF) located on the Caribbean island of Puerto Rico has a rich history of ecological research, including a variety of avian studies, and is one of the most active ecological research sites in the Neotropics. The LEF spans an elevational range from 100 to 1075 m over which five life zones and four forest types are found in a warm, humid subtropical climate. A total of 23 bird species breeds here and another 76 species, mostly migrants, are known to occur. The food web of the forest in the lower elevations is especially well studied, which allows an assessment of the role of birds in the food web. The LEF is noted for its high densities of Eleutherodactylus frogs and Anolis lizards, which may depress insect densities thereby contributing to the low species richness and densities of most insectivorous birds. The signature species of the forest is the endangered Puerto Rican Parrot (Amazona vittata) that has been the focus of intensive long-term research and recovery efforts, which have spawned research on associated species, including long-term studies on the Pearly-eyed Thrasher (Margarops fuscatus) and botfly (Philornis spp.) ectoparasitism. Given the frequency of hurricane disturbance to the LEF and studies providing baseline for comparisons, research has made major contributions to an understanding of the effects of hurricanes on forest ecosystems including bird populations and their resources. We summarize these and other studies from the LEF to characterize the avifauna and its environment while noting studies with management implications and identify opportunities for future ornithological studies. 相似文献
90.
[目的]探讨Ni2+胁迫对水稻及白菜种子萌发和生长影响,以比较二者对Ni2+胁迫的耐受力。[方法]水培条件下研究不同浓度Ni2+胁迫对水稻和白菜种子发芽率、根伸长及早期植物幼苗生长的影响。[结果]低浓度Ni2+胁迫对水稻及白菜种子发芽率均无显著影响,处理浓度增至30.0 mg/L时水稻种子发芽率与对照及同浓度下白菜种子发芽率相比显著降低;1.5 mg/L及以下处理浓度可刺激水稻根伸长,3.0 mg/L以上处理浓度则抑制水稻根生长;1.5 mg/L处理浓度Ni2+胁迫至96 h可显著刺激白菜根的伸长,处理浓度达30.0 mg/L时各个胁迫时间均可显著抑制根的伸长;3.0 mg/L处理浓度下胁迫96 h水稻根长显著短于白菜根长。Ni2+胁迫对水稻及白菜芽长影响较小,72 h内各个处理浓度下水稻及白菜芽长与对照相比均无显著差异;而对于侧根影响最为明显,30.0 mg/L处理浓度下水稻和白菜均无侧根产生。1.5 mg/L及以上处理浓度胁迫均可显著抑制水稻及白菜鲜质量增加,但二者未表现出显著差异。[结论]Ni2+胁迫对于水稻种子萌发及其生长影响较白菜敏感。 相似文献