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1.
ZHANG Feng-lu NIU Xing-kui ZHANG Yi-ming XIE Rui-zhi LIU Xin LI Shao-kun GAO Shi-ju 《中国农业科学(英文版)》2013,(3):426-435
Experiment was conducted at the Gongzhuling Experimental Station of Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Jilin Province, China, during 2009-2010. Six representative varieties of maize (Baihe in the 1950s, Jidan 101 in the 1960s, Zhongdan 2 in the 1970s, Yedan 13 in the 1980s, Zhengdan 958 in the 1990s, and Xianyu 335 in the 2000s) were each planted under two different densities (52 500 and 82 500 plants ha-1) and two different nitrogen application levels (150 and 300 kg ha-1). Root characteristics and distribution among soil layers were studied by the field root digging method. The results showed that root mass increased with the process of the growth and development of the plant, and it peaked at kernel filling stage, and decreased at maturity due to the root senesces. Root mass of different maize varieties from the 1950s to 1980s had a trend of increase, while it decreased for the modern varieties. Root length and root surface areas had the similar changing trend. The study suggested that early maize varieties may have root redundancy, and reducing root redundancy may be a direction for variety improvement for high yield. Root characteristics were affected by nitrogen application level and density; modern varieties were more suitable for higher fertilizer application level and density conditions. Root characteristics distribution among soil layers decreased by an exponent equation, but the regression coefficients of different varieties were different. Though the root length density (RLD) of every soil layer of different varieties also decreased by an exponent equation, there were large variations of RLD in every part of a layer. 相似文献
2.
Over the past two years, an abnormal growth phenomenon Jiangsu Province of China. The phenomenon is described in called shrunk-grain panicle has occurred in a large area in details by figures and characters in this article. The method with a japonica rice Wuyujing 3 as the experimental material, the characteristics of grain morphology distribution and the grain weight were studied. Normal and shrunk-grain panicles were sampled from several representative areas. The length, width, and weight of the normal grains were distributed as regular, continuous, and single peaks. Plant growth typically had a right-leaning tendency. On the contrary, the distribution of the grain morphology and weight were irregular and nearly double that of the shrunk-grain panicle. The proportion of the cumulative distribution in the two kinds of peaks was closely related to the degree of shrunk-grain panicle. The article discusses the phenomenon＇s symptoms, problems, and diagnosis. 相似文献
3.
宁夏沙坡头人工植被区土壤真菌种群的动态研究(英文) 总被引：5，自引：0，他引：5
[Objective] The changes of fungi in different soil layers and sand dunes of artificial vegetation areas in Ningxia Shapotou during different times were studied. [Method]The number of soil fungi in different soil layers at same plot and in same soil layer at different plots were changed significantly.The quantitative distribution of fungi was the most in Cuiliugou but the fewest in quicksand among all soil types.[Result] The quantity of soil fungi in grasslands was varied in different soil layers at the same sample and in the same soil layer at different sample plots. The quantity of fungi from different soil types distributed mostly in Cuiliugou, a natural desert steppe, but little in quicksand. The species and quantity of fungi in CuiLiugou was the most in different types of sand-fixing lands. [Conclusion] The quantity of soil fungi in artificial vegetation areas raises with the increase of sand-fixing ages, The enhancement of vegetation construction and artificial management measures in inland is helpful for improving present situation of desertification. 相似文献
4.
The purpose of this paper is to revise and supplement present information regarding;1)Grade One and Grade Two areas of Yunnan zoogeographical areas,2) the founda-tion of vertebrate divisions of zoogeographical areas of china and 3) the fauna studies ofYunnan. After discussion,the paper puts forward a new idea that there are three,ratherthan two animal divisions of Yunnan like the previous notion. This new idea is based onFresh research at previous information including:1) regional divisions brought about byecological differences of varying areas of Yunnan,2) different vegetation types inYunnan,and 3) the differences of species and subspecies grades of fauna in Yunnan.Finally,the paper assert that the fauna of Yunnan can be divided into 3 areas of GradeOne,4 areas of Grade Two and 10 areas of Grade Three. 相似文献
5.
LIU Hua-zhen TANG Wen-hua PENG Ke-mei CHEN Wen-qin LUO Guan-zhong WANG Yan WEI Lan 《中国农业科学(英文版)》2006,5(6):473-477
Healthy Cherry Valley ducks were used in the present study. Different doses of tryptophan were injected intraperitoneally to them after being fasted 4 h （8：00 a.m.-12：00 a.m.）. One hour later, they were deeply anaesthetized and perfused. The cerebellum was removed to make serial paraffin longitudinal sections. The streptavidin-biotin-peroxidase complex （SABC） method was used to study the distribution of serotonin-like neurons in the cerebellum. All films were analysed by using a computer-assisted image analysis system. Serotonin-like neurons are only localized in cerebellar Purkinje cell layer. The optical density averages of serotonin-like neurons in 200 and 100 mg kg^-1 group are significantly higher than that of 0 mg kg^-1 group （P〈0.01）. These results show that serotonin-like neurons are distributed in Purkinje cell layer and that excessive tryptophan can affect the content of serotonin in cerebellum. 相似文献
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瓦螨微生物防治的不良效果 总被引：1，自引：0，他引：1
We report six different field trials testing the efficacy of Metarhizium anisopliae,an entomopathogenic fungus,against varroa mites in honey bee hives.Varroa mites are parasitic on honey bees and cause serious damage to Apis mellifera colonies.Several control methods are available for varroa mites,none are very effective,so new,more effective methods are being sought.Varroa has previously been shown to be highly susceptible to M.anisopliae infections,and in our first two field trials,we found some efficacy from spore applications.However,in subsequent field trials,we were not able to obtain any varroa control, despite attempting several different application methods, two different strains of the fungus, and testing in different climates and during different phenological states of the honey bee colony. We conclude that microbial control of varroa using fungi is not likely to be effective unless some way is found to prolong the survival of the spores (or other infective units) in the hive environment. 相似文献
8.
LIJian LIMei-gui 《中国农业科学(英文版)》2004,3(7):509-518
There are two kinds of theoretical defects export in the diagnosis and recommendation integrated system (DRIS): the distribution of nutrient elements ratios with two normal distribution displays an abnormal distribution of positive skewness; there is a blind diagnostic area by DRIS on the occasion of the nutrient elements with equal ratios but without equal quantity. In the light of the quadratic form theory of multidimensional normal distribution and the view of balance of equal probability, the balance diagnosis and recommendation integrated system (BDRIS) was developed in this paper, which is superior to DRIS and its diagnosis method is unified to critical value diagnosis. When the correlation matrix of nutrient elements R= I(identity matrix), i.e., the effects of elements antagonism is disregarded, BDRIS will be simplified into the critical value diagnosis. In addition, the diagnosis program written in SAS language was also provided in this paper. 相似文献
9.
Sawsan Atallah Oran 《农业科学与技术》2014,(6):461-467
The taxonomic status of the medicinal plants in Jordan is expressed in terms of its diversity, the documentation of the scientific research that is carried out locally over the last many years; to test for the potential of some medicinal plant species （MPS） in Jordan on different biological aspects is also prepared. This has been reported here by revising and documenting the available literature to the author on this subject. The ecological status of medicinal plants in Jordar is also pointed out. The aim of this research was mainly to evaluate the status of the research on medicinal plants that was carried oul： to test for the different biological potentials of medicinal plants in Jordan and to emphasis the richness of the country of its wild medicinal plants, which are of promising value in whether for use in traditional medicine or in pharmaceutical industry, and certainly need lots of investigations and scientific research. Photographs of some medicinal plants that are common in Jordan and are used in traditional medicine in the urban areas and the Badia region, which is located in the Eastern part of the country and characterized by its dry weather conditions and least amount of rainfall in the country, are also included; the plant photographs are selected from different representative families of the common flowering plants in Jordan. 相似文献
10.
Spatio-temporal relationship of the phytophagons Clania miniscula （Butler） and garden spiders was examined through analysis of their niche and distribution as they occur in sasanqua orchard in Southern Anhui, China from June 2003 to May 2004. The dynamic relationships between Clania minuscula and garden spiders were seasonal in time and space. Spatio-temporal niche breadth was high for the two groups, ranging from 0.57 to 0.98; niche overlap was also high between the two groups from 0.76 to 0.96 during the seasons of June 2003 to May 2004. Geostatistical results indicated that Clania minuscula and garden spiders were aggregated during the emergence periods. The pest Clania minuscula was spatially dependent to a range from 33.48 to 46.84 m while spatial dependence from 30.93 to 51.11 m for garden spiders. The correlation analysis of distribution maps further illustrate the distribution of garden spiders always coincided with that of Clania minuscula. These results showed spatio-temporal synchrony of Clania minuscula and garden spiders at different periods. Adequate knowledge of spatio-temporal correlation between Clania minuscula and garden spiders contributed to provide information for biocontrol at different periods in sasanqua orchard. 相似文献
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[目的]研究GABAergic神经元在VPM和"barrel"区的组织结构及形态特点;[方法]通过免疫组织化学的方法和激光共聚焦电子显微镜研究GABAergic神经元在VPM和"barrel"区分布状态;[结果]GABAergic神经元在VPM和"barrel"区分布状态不同,信息传递这2个区域编码程度也不一样;GABAergic在VPM区主要分布在列与列之间,且呈非对称分布,而GABAergic神经元的胞体、树突和轴突出现限定在"barrel"内,与周围"barrel"很少形成突触联系。[结论]提示VPM和"barrel"可能在信息传递及处理过程中具有不同的功能。 相似文献
13.
Melzer S Michael M Caputi A Eliava M Fuchs EC Whittington MA Monyer H 《Science (New York, N.Y.)》2012,335(6075):1506-1510
The hippocampus and entorhinal cortex play a pivotal role in spatial learning and memory. The two forebrain regions are highly interconnected via excitatory pathways. Using optogenetic tools, we identified and characterized long-range γ-aminobutyric acid-releasing (GABAergic) neurons that provide a bidirectional hippocampal-entorhinal inhibitory connectivity and preferentially target GABAergic interneurons. Activation of long-range GABAergic axons enhances sub- and suprathreshold rhythmic theta activity of postsynaptic neurons in the target areas. 相似文献
14.
Del Bene F Wyart C Robles E Tran A Looger L Scott EK Isacoff EY Baier H 《Science (New York, N.Y.)》2010,330(6004):669-673
The optic tectum of zebrafish is involved in behavioral responses that require the detection of small objects. The superficial layers of the tectal neuropil receive input from retinal axons, while its deeper layers convey the processed information to premotor areas. Imaging with a genetically encoded calcium indicator revealed that the deep layers, as well as the dendrites of single tectal neurons, are preferentially activated by small visual stimuli. This spatial filtering relies on GABAergic interneurons (using the neurotransmitter γ-aminobutyric acid) that are located in the superficial input layer and respond only to large visual stimuli. Photo-ablation of these cells with KillerRed, or silencing of their synaptic transmission, eliminates the size tuning of deeper layers and impairs the capture of prey. 相似文献
15.
Diazepam-binding inhibitor: a neuropeptide located in selected neuronal populations of rat brain 总被引：15，自引：0，他引：15
H Alho E Costa P Ferrero M Fujimoto D Cosenza-Murphy A Guidotti 《Science (New York, N.Y.)》1985,229(4709):179-182
An endogenous polypeptide of rat brain has been identified that is capable of displacing 1,4-benzodiazepines and the esters of the 3-carboxylic acid derivatives of beta-carbolines from their specific synaptic binding sites. This polypeptide was termed diazepam-binding inhibitor (DBI). Previous studies have shown that DBI injected intraventricularly in rodents elicits "proconflict" responses and antagonizes the "anticonflict" action of benzodiazepines. An antiserum to this peptide, directed toward an immunodeterminant near its amino terminus, makes it possible to detect, measure, and study the neuronal location of this peptide in rat brain. In the rat cerebral cortex, DBI immunoreactivity is located in neurons that are not GABAergic (GABA, gamma-aminobutyric acid); in the cerebellum and hippocampus, however, it might be present also in GABAergic neurons. 相似文献
16.
铜陵市"国际华城"小区地块位于铜陵经济技术开发区,设计采用新古典主义建筑风格,以华贵承享自然,景城传释人生,拓展美好的生态与文态园林景观为主题。功能结构组织上强调"一心","二轴","三体现",将小区划分为"四区"及"五境","十景","多丘"主要景观节点。通过本设计,使"国际华城"居住区环境景观形态成为表达整个居住区形象、特色以及可识别性的载体。 相似文献
17.
以JCR2002期刊的学科分布为依据,从统计的角度得出SCI期刊的学科分布情况及各学科对应期刊的指标分布情况.验证了SCI期刊学科结构的不均衡性.提出了不同学科之间SCI论文评价的设想,并以本校两课题组论文评价为实例进行了对比分析. 相似文献
18.
Nie Z Schweitzer P Roberts AJ Madamba SG Moore SD Siggins GR 《Science (New York, N.Y.)》2004,303(5663):1512-1514
The central amygdala (CeA) plays a role in the relationship among stress, corticotropin-releasing factor (CRF), and alcohol abuse. In whole-cell recordings, both CRF and ethanol enhanced gamma-aminobutyric acid-mediated (GABAergic) neurotransmission in CeA neurons from wild-type and CRF2 receptor knockout mice, but not CRF1 receptor knockout mice. CRF1 (but not CRF2) receptor antagonists blocked both CRF and ethanol effects in wild-type mice. These data indicate that CRF1 receptors mediate ethanol enhancement of GABAergic synaptic transmission in the CeA, and they suggest a cellular mechanism underlying involvement of CRF in ethanol's behavioral and motivational effects. 相似文献
19.
龙永红 《湖南农业大学学报(自然科学版)》2015,(2):1-6
传统的H∞鲁棒控制器通常都是基于线性矩阵不等式求解的,因此阶次较高,不利于实现,而基于Nevanlinna-Pick插值的H∞鲁棒控制器设计方法能够有效的解决这一问题。本文提出一种改进的同伦算法用于求解控制器设计过程中出现的非线性方程,避免了经典同伦法中逆矩阵的求解。针对某一跟踪系统设计基于Nevanlinna-Pick插值的H∞鲁棒控制器,通过阶跃响应和正弦信号的跟踪响应可以看出,与高阶超前滞后校正环节相比,前者构成闭环系统的跟踪精度要比后者的控制精度高,且具有较强的鲁棒稳定性。 相似文献
20.
Relationships between the M and P retino-geniculo-cortical visual pathways and "dorsal" visual areas were investigated by measuring the sources of local excitatory input to individual neurons in layer 4B of primary visual cortex. We found that contributions of the M and P pathways to layer 4B neurons are dependent on cell type. Spiny stellate neurons receive strong M input through layer 4Calpha and no significant P input through layer 4Cbeta. In contrast, pyramidal neurons in layer 4B receive strong input from both layers 4Calpha and 4Cbeta. These observations, along with evidence that direct input from layer 4B to area MT arises predominantly from spiny stellates, suggest that these different cell types constitute two functionally specialized subsystems. 相似文献