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31.
谷子(粟)壮苗与弱苗之比较研究 总被引:1,自引:0,他引:1
以田间和盆栽试验方法比较了谷子壮苗与弱苗形态、生理的差异 ,以及与生态条件的关系。结果表明 ,壮苗的形态粗壮墩实 ,生长齐整 ,叶色浓绿 ,在拔节时根数达 15~ 16条 ,苗高 4 0~ 4 5cm ,苗粗 >0 .5cm ,叶数 7~ 8片 ,叶宽为叶长的 1/ 10左右 ,幼苗充实度 15~ 2 0mg/cm。壮苗的生理基础是根系活性强 ,伤流量比弱苗高 2倍左右 ,地上部生理活性高 ,叶面积大 1倍左右 ,光合速率提高4 6 .8% ,干物质量大 1.8倍 ,NAR达 8~ 9g/m2 ·d ,体内物质向根和叶鞘分配的比率多 1.6 8和 1.74个百分点 ,体内可溶性糖含量高 50 %以上 ,因而幼苗生长健壮 相似文献
32.
云杉属木材生长轮宽度变异系数对声振动参数的影响 总被引:3,自引:0,他引:3
选择7种我国主要的云杉属树种木材和1种作对比用的美国产西加云杉,进行了弯曲振动条件下各项声振动特性参数的检测和比较,初步分析了这些振动参数与木材构造中生长轮宽度变异系数之间的关系。结果表明:生长轮宽度比较均匀的木材具有比较好的声学振动特性。 相似文献
33.
基于功率谱密度的蛋鸡声音检测方法 总被引:2,自引:0,他引:2
利用声音连续监测动物生长过程的缺点是无效声音数据量大。为了获得便于研究人员使用的小数据量并同时反映动物行为信息的声音,引入分类识别方法对原始声音进行处理。以栖架饲养环境中的含有海兰褐蛋鸡鸣叫声的声音片段和风机噪声片段为研究对象,基于不同类型声音在1 000~1 500 Hz频率范围内的功率谱密度存在差异,对2种声音片段进行了分类识别。试验结果表明,该方法的全面正确识别率为95%,其中蛋鸡声音片段正确识别率为93.3%。该方法将有助于实现风机噪声环境中动物声音实时检测与提取,从而减少无用声音数据的储存与传输。 相似文献
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Lancaster Surecrop (LSC) germplasm in inbreds of the Lancaster heterotic group in China was mainly provided by the two inbreds Mo17 and Oh43. Furthermore, the source of LSC germplasm was severely restricted in two inbreds, C103 and Oh40B. The contents of LSC germplasm are 50% or less in inbreds of the group, with the existence of more than 20 non-LSC germplasms that results in the abundant genetic diversity in the group. Most inbreds of Mo17 subgroup contain 25 % - 50 % LSC, 12.5 % - 25 % Reid Yellow Dent (RYD)and 12.5% - 25% Iowa Goldmine germplasms in the ratio of 2:1:1, and most inbreds of Zi330 subgroup contain 12.5%-25% LSC, 6.25%- 12.5% RYD, 6.25%- 12.5% Minnesota # 13 and 25%- 50% Creole germplasms in the ratio of 2:1:1: 4. All the facts indicated that the germplasm base of the Lancaster heterotic group has stupendously changed and evolved away from actual LSC germplasm. 相似文献
36.
From 1994 to 1998, a multidisciplinary ecosystem study (the Sound Ecosystem Assessment) examined the primary physical and biological factors that influence the production of pink salmon and Pacific herring in Prince William Sound (PWS), species that experienced population declines after the 1989 Exxon‐Valdez oil spill. Three physical processes are described that influence ecosystem processes: surface layer stratification; upper layer (<100 m) circulation; and exchange between PWS and the northern Gulf of Alaska (NGOA). Stratification formed first in the PWS nearshore regions in March, and subsequently in the northern central basin in April, primarily due to freshening. The northern stratified layer and the associated zonal density front persisted at least through June, but year‐to‐year differences occurred. In spring and summer, circulation in central PWS could be either cyclonic or anticyclonic. Drifter trajectories often linked central PWS to a nearshore bay or fjord, or one bay or fjord to another. September was characterized by a cyclonic circulation and isopycnal doming in central PWS, with little year‐to‐year variability. At Hinchinbrook Entrance, a main connection with the Gulf of Alaska, alternating inflows and outflows occurred in spring over all depths. In summer through early autumn (1995), in the absence of predominantly westward winds, the dominant exchange pattern was outflow above about 150 m and inflow below. In summer through early autumn (1996–98), there was also surface (<20 m) inflow at Montague Strait (the other main entrance). Northward transport at Hinchinbrook Entrance was maximum in late autumn through winter, with inflow above ~150 m and outflow below. Westward wind events over the shelf associated with the weather cycle drove inflow events at both Hinchinbrook Entrance and Montague Strait that may result in transport of zooplankton important to the PWS ecosystem. 相似文献
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ABSTRACT: The mechanisms by which catch yields of the manila clam Ruditapes philippinarum have decreased drastically in Kumamoto Prefecture, southern Japan, and the larval recruitment by which benthic populations of the clam are maintained were studied. Samples at different growth stages (planktonic larvae, new settlers, and small to large bivalves of the species) were collected from February 1997 to December 1998 on two tidal flats (Kawaguchi and Nameishi, 20 km distance from each other) along the eastern coast of Ariake Sound. Densities of planktonic larvae, new settlers and small bivalves were generally higher at Kawaguchi than Nameishi. The higher density of large bivalves at Kawaguchi depends on a high larval density. Larval retention mechanisms coupled with water movement at Kawaguchi, such as tidal residual currents, may be related intimately with the higher larval density at Kawaguchi. Predation by shore birds at and after recruitment may be related to the lower density of large bivalves recorded at Kawaguchi in 1998, despite larval densities being higher there. 相似文献
39.
[目的]初步研究复合声频刺激对大肠杆菌生物学特性的影响作用。[方法]采用自行研制的声频发生装置,以大肠杆菌为研究对象,进行声波刺激试验。[结果]结果表明,在固定声频的情况下,随着刺激强度的增加,大肠杆菌的繁殖速率、代谢活性显著增强,并最终呈现出一种"饱和"现象;但随着刺激强度的进一步增加,大肠杆菌的生长却表现为明显的抑制效应。在声频、刺激强度一定的情况下,大肠杆菌在不同培养底物上的生长特性也表现出明显差异,其中在LB液体培养基中被明显促进,而在BPY液体培养基中则表现为抑制效应。[结论]声波刺激对大肠杆菌的生长及代谢具有显著影响。 相似文献
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