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81.
The entomopathogenic fungus,Beauveria bassiana (Balsamo) Vuillemin, was applied to whorl-stage (V7) corn,Zea mays L., by foliar application of a granular formulation of corn grits containing conidia or by injection of a conidial suspension.
All plants were infested with European corn borer larvae,Ostrinia nubilalis (Hübner), at the V7 (whorl), V12 (late-whorl), or V17 (pretassel) stage of plant development. Plants infested at whorl and
late-whorl stages had significantly more European corn borer tunneling than did plants infested at the pretassel stage. The
percentage of plants colonized byB. bassiana did not differ significantly among the whorl, late-whorl, and pretassel stages. As the plants matured,B. bassiana was isolated from different plant areas, with the pith more frequently colonized than the leaf collars. Foliar application
ofB. bassiana provided immediate suppression ofO. nubilalis in those plants infested at whorl stage. The reduced efficacy ofB. bassiana at the intermediate plant stages relative to efficacy at harvest is discussed.
The mention of firm names or trade products does not imply that they are endorsed or recommended by the U.S. Department of
Agriculture over other firms or similar products not mentioned. 相似文献
82.
Abstract. Microscale variation of vegetation was studied in a Mediterranean oak savanna dominated by annual plants at Neve Ya'ar Experimental Station, in the lower Galilee of Israel. Species presence/absence data were recorded in 20 cm x 20 cm quadrats on a 500-quadrat transect. These data were ordinated with Detrended Correspondence Analysis. Soil nitrate, phosphorous, potassium, pH, soil moisture and salinity were determined at 2-m intervals on the 100-m transect, at monthly intervals from November 1981 to April 1982. Litter cover and canopy shade were surveyed in October 1981 and April 1982. A sharp rise in available nitrate occurred in November, following the first winter rains. Patterns in herbaceous vegetation, as expressed by sample ordination scores, correlated best with litter cover in October. This suggested that vegetation pattern in this community may be strongly influenced by environmental conditions at the time of seedling germination and establishment. 相似文献
83.
Summary In the Dashte-Arjan area near Shiraz, rock formations appear to control the distribution of various plant species. The Fars formation (Miocene) and the Asmari-Jahrom formation (Eocene-Oligocen) sediments are characterized by distinet plant species and life forms. Among the characteristic calciphytes of Asmari-Jahrom limestones are Astragalus acutus, Amygdalus lyciodes, Cerasus microcarpa, and Fraxinus rotundifolia. The Fars formation limestones are characterized by Astragulus gossypinus, Acantholimon flexuosum, Noaea mucronata and Phlomis bruguieri, Except for Glycrrhiza glabra, white and red marls seem to have similar species, such as Alhagi maurorum and Carthamus oxyacantha. Gypsum of Fars formation has Berberis integerrima and Rosa beggeriana. Various life forms have been distinguished and were found to be confined to different rock types as well.Nomenclature of species is given in table 1.We are greately indebted to Dr. P.H. Davis and Prof. G. Pontecorvo F.R.S. for critically reading this paper and making some invaluable suggestions. We are grateful to the University Research Grant Commission for providing us a grant for this work. We are also indebted to the Dean, College of Arts & Sciences, Pahlavi University, Shiraz, Iran for providing us with a vehicle during this work. 相似文献
84.
Ammonia-nitrogen excretion in Daphnia pulex 总被引:3,自引:2,他引:1
Ammonia-nitrogen excretion rates were measured in natural summer and cultured populations of Daphnia pulex from Silver Lake, Clay County, Minnesota, USA during 1973. The mean rate of ammonia-nitrogen excretion for the summer populations was 0.20 µg N animal–1 day–1 or 5.11 µg N mg–1 dry body weight day–1 (N = 80) measured at 15°, 20°, and 25°C. These rates appear to be temperature and weight dependent, but they are probably affected by factors other than temperature and dry body weight. Ammonia-nitrogen excretion rates of Daphnia pulex cultured on Chlamydomonas reinhardi yielded the following relationship with temperature: Log10E = (0.061) T 1.773, where E is µg N animal–1 day–1 and T is temperature °C. The ammonia-nitrogen excretion on a mg–1 dry body weight day–1 basis was related to temperature according to the following similar expression Log10E = (0.043) T + 0.153, where E is µg N mg–1 dry body weight day–1, and T is temperature °C. The length-weight relationship of Daphnia pulex for the summer populations (N = 1583) was log10W = (0.526) Log10L + 1.357, where W is weight in µg and L is length in mm. 相似文献
85.
Electron microscope observations were made of the Australian and U.S. strains of Culicinomyces clavisporus infecting mosquito larvae. The wall of the conidium is composed of an inner (primary) layer, an outer (secondary) layer, and an exterior coating of a mucopolysaccharide substance believed responsible for conidial adhesion to the host cuticle prior to germination and penetration. In some instances the wall of the conidium is ruptured during germination and new wall layers and mucoid coating form around the germ tube whereas in other specimens the conidial wall layers extend around the germ tube without fracturing. The most common invasion site is through the larval foregut following ingestion of conidia. The apex of the germ tube presses tightly against the surface of the foregut cuticle and the mucilaginous coating is stripped away. There is evidence to suggest that the host epicuticle, which disappears across the zone of contact with the germ tube, is utilized for nutrition of the invading fungus. A collar of cuticle forms around the germ tube apex and a narrow penetrant hyphae extends into the procuticle. It is believed that cuticular penetration is primarily enzymatic assisted by mechanical pressure. The penetrant hypha swells into an oval cell in the hypodermal region and vegetative hypha then invade the hemocoel. The cells of the hypodermis develop signs of degeneration presumably due to the secretion of toxic substances from the invading hyphae. Host reactions, involving melanization of the host tissues, are sometimes evident among the invading penetrant hyphae in the cuticle or in the hypodermal cells in contact with the fungus. Melanized capsules form around some of the hyphae within the hemocoel. These latter reactions do not directly involve host blood cells and are examples of “humoral encapsulation” similar to that described by other authors during invasion of pathogenic organisms into mosquito larvae and chironomid larvae. 相似文献
86.
《Bioorganic & medicinal chemistry》2019,27(18):4110-4123
The sulfonamidophenylethylamide analogues were explored for finding novel and potent cardiac myosin activators. Among them, N-(4-(N,N-dimethylsulfamoyl)phenethyl-N-methyl-5-phenylpentanamide (13, CMA at 10 µM = 48.5%; FS = 26.21%; EF = 15.28%) and its isomer, 4-(4-(N,N-dimethylsulfamoyl)phenyl-N-methyl-N-(3-phenylpropyl)butanamide (27, CMA at 10 µM = 55.0%; FS = 24.69%; EF = 14.08%) proved to be efficient cardiac myosin activators both in in vitro and in vivo studies. Compounds 13 (88.2 + 3.1% at 5 µM) and 27 (46.5 + 2.8% at 5 µM) showed positive inotropic effect in isolated rat ventricular myocytes. The potent compounds 13 and 27 were highly selective for cardiac myosin over skeletal and smooth muscle myosin, and therefore these potent and selective amide derivatives could be considered a new class of cardiac myosin activators for the treatment of systolic heart failure. 相似文献
87.
Roger Scholz Falk Hoffmann Sandra von Sachsen Welf-Guntram Drossel Carsten Klöhn Christian Voigt 《Journal of biomechanics》2013
In total hip arthroplasty and particularly in revision surgery, computer assisted pre-operative prediction of the best possible anchorage strategy for implant fixation would be a great help to the surgeon. Computer simulation relies on validated numerical models. In the current study, three density–elasticity relationships (No. 1–3) from the literature for inhomogeneous material parameter assignment from CT data in automated finite element (FE) modeling of long bones were evaluated for their suitability for FE modeling of human pelvic bone. Numerical modal analysis was conducted on 10 FE models of hemipelvic bone specimens and compared to the gold standard provided by experimental modal analysis results from a previous in-vitro study on the same specimens. Overall, calculated resonance frequencies came out lower than measured values. Magnitude of mean relative deviation of numerical resonance frequencies with regard to measured values is lowest for the density–elasticity relationship No. 3 (−15.9%) and considerably higher for both density–elasticity relationships No. 1 (−41.1%) and No. 2 (−45.0%). Mean MAC values over all specimens amount to 77.8% (No. 1), 78.5% (No. 2), and 83.0% (No. 3). MAC results show, that mode shapes are only slightly influenced by material distribution. Calculated resonance frequencies are generally lower than measured values, which indicates, that numerical models lack stiffness. Even when using the best suited (No. 3) out of three investigated density–elasticity relationships, in FE modeling of pelvic bone a considerable underestimation of model stiffness has to be taken into account. 相似文献
88.
Ahlam Sayout Aicha Ouarhach Reda Rabie Ilham Dilagui Nabila Soraa Abderrahmane Romane 《化学与生物多样性》2020,17(1)
The genus Lavandula is known for its different uses in traditional medicine. This study is interested in the chemical composition of Lavandulapedunculata subsp.atlantica (Braun‐Blanq. ) Romo as well as evaluating its antibacterial potential against multi‐resistant strains. The analysis of Lavandulaatlantica essential oil (LAEO) allows the identification of 47 components representing 93.6 % of all identified. The main constituent of LAEO was camphor (50.4 %), followed by fenchone (14.1 %) and camphene (5.6 %). The antibacterial assays revealed that LAEO was active against all the studied bacteria. A preliminary study of the relationship between certain terpenoids and antibacterial activity was also carried out in order to note the compound(s) that are responsible for LAEO's antibacterial activity. This study showed that the activity of the essential oil may be due to the presence of certain minor compounds such as carvone, considering the presence of the synergistic effect between the essential oil. 相似文献
89.
90.
对第三纪孑遗濒危植物矮扁桃(Amygdalus nana)叶绿体全基因组进行结构特征分析,并探究其与近缘物种之间的系统进化关系。利用Illumina HiSeq Xten测序技术获取叶绿体全基因组序列,对其进行组装、注释和特征分析。结果表明:①矮扁桃叶绿体全基因组总长度为158 596 bp,其中LSC长度为86 771 bp,SSC长度为19 037 bp,2个IRs均为26 394 bp,为环状四分体结构。共注释130个基因,包括85个PCGs、37个tRNA和8个rRNA。②对6种植物进行IR边界区扩张和收缩分析,发现在4个边界区的基因类型和基因分布情况存在一定差异,并且亲缘关系越紧密差异程度越小。③在矮扁桃叶绿体全基因组中共预测了71个SSRs位点。④系统发育分析结果显示,在扁桃亚属中,矮扁桃在亲缘关系上与蒙古扁桃更近,而与长柄扁桃和榆叶梅的亲缘关系稍远。本研究对矮扁桃叶绿体全基因组进行了深度剖析,并且涉及大量被子植物的叶绿体全基因组资料,为桃属植物之间的进化关系和植物鉴定提供参考依据。 相似文献