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1.
污泥施用对4种绿化植物叶片性状和光合作用的影响 总被引：4，自引：2，他引：2
通过向种植土内添加不同比例的污泥用量,观测盆栽绿化植物叶片性状和光合生理的变化,筛选不同植物的适宜污泥用量。结果表明,‘金叶’梓树和‘红叶’石楠以25.0%浓度处理下,植物叶片性状和光合生理表现最强,可提高比叶面积、净光合速率和叶绿素含量;‘紫花’海棠也表现为相似的生理响应,改变各项生理指标以适应添加污泥的土壤,以12.5%含量处理效果佳。相反,乌桕的表现较差,随着浓度增加表现越差。建议在用封场土种植绿化植物时最多可添加25.0%的生污泥,绿化植物可选择‘金叶’梓树和‘红叶’石楠。 相似文献
2.
连作草莓根际土壤特征及修复技术研究进展 总被引：2，自引：1，他引：1
连作障害是制约草莓(Fragaria ananassa)发展的最大因素。笔者对国内外草莓连作障害的研究亮点进行了综述。土壤根际微生物区系变化,有益微生物减少,病原菌增加,有害化感物质积累是产生连作障害的主要原因。杀灭土壤病原菌,去除有害化感物质,把“病土”修复成“健康土”,是克服连作障害,实现草莓连茬种植的根本之路。对草莓连作障害机理的深入研究、土壤修复技术的应用研究仍然是未来发展的方向。 相似文献
3.
基于统计数据的中国农产品物流与农业增长的关系研究 总被引：1，自引：1，他引：0
以农产品物流与农业增长统计数据为研究对象,对农产品物流与农业增长间的相关关系以及长短期关系进行研究,旨在探究和评价中国农产品物流发展与农业增长的现状、存在的问题,并提出相应的改进建议和对策,为相关领域的研究打好理论基础。笔者认为,农产品物流总额的增长与农业GDP增长存在着强相关关系、长期平衡关系和短期波动关系。 相似文献
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基于HJ1A-HSI超光谱影像的县域耕地土壤盐渍度预测研究 总被引：2，自引：0，他引：2
针对目前干旱半干旱地区存在的土壤盐渍化问题,以北疆典型盐渍化地区玛纳斯县为研究区,以HJ1A-HSI超光谱影像为主要数据源,结合实测耕地土壤含盐量,分析光谱反射率及其变化形式与盐分含量的相关性,筛选耕地盐分响应的敏感波段,利用多元回归分析方法,建立基于环境卫星影像的耕地含盐量定量反演模型。结果表明,盐分的HSI影像响应波段均位于可见光与近红外波段间,以500~549 nm和696~776 nm范围最佳,相关系数均大于0.5;HSI反射率对数(lgP)预测模型精度最高,可实现对研究区耕地土壤盐分遥感反演。 相似文献
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烤烟品种‘K326’不同部位适宜成熟度采收研究 总被引：1，自引：1，他引：0
采用田间试验研究了烤烟‘K326’ 品种不同部位成熟采收的标准。结果表明,烤烟品种‘K326’下部叶在5成熟时采收表现较好,香气量足,浓度高,杂气和刺激性均较小;中部叶8成采收,烘烤质量最好,颜色鲜亮、油分多,单叶重较重;上部叶在9成黄时采收的表现最好,香气量足,杂气和刺激性均低。试验结果对烤烟品种‘K326’的种植及提高其产质量具有重要意义。 相似文献
8.
棘孢木霉T4小分子疏水蛋白基因hyb2克隆及序列分析 总被引：1，自引：1，他引：0
为了深入研究生物防治菌棘孢木霉T4菌株小分子疏水蛋白hyb2的功能,基于已知小分子疏水蛋白基因hyb2部分cDNA序列设计引物,分别以棘孢木霉T4菌株菌丝体总mRNA和基因组DNA为模板,进行PCR扩增,克隆获得hyb2的全长cDNA和DNA序列,其GenBank接受号分别为JX014433和JX185070,cDNA序列编码区长度为321 bp,编码106个氨基酸。BlastP相似性分析表明该基因与深绿木霉的Tahyd5a (ABS59366)基因同源性最高为87%,SignalP信号肽分析表明N端第16和17个氨基酸中间有一个信号肽剪切位点(AFA||AP)。Pfam蛋白家族分析表明它属于hydrophobin_2 superfamily家族。将棘孢木霉T4菌株小分子疏水蛋白基因hyb2对深绿木霉ATCC74058基因组和绿色木霉Gv29-8基因组进行同源性搜索,在2个近缘种的基因组上分别获得9个和8个同源序列。其中,深绿木霉ATCC74058的hyb-a-7和绿色木霉Gv29-8的hyb-v-5疏水蛋白与棘孢木霉Hyb2相似性最高分别为87%和70%,2个序列分别位于深绿木霉ATCC74058染色体骨架5和绿色木霉Gv29-8染色体骨架22上。 相似文献
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为了探索Mopos5可能参与的信号网络,了解其作用的分子机制,利用酵母双杂交系统筛选了稻瘟病菌cDNA文库,获得了6个与Mopos5互作的蛋白;结合生物信息学预测分析和相关文献报道,发现这些候选互作蛋白很可能参与调控了细胞骨架建成、细胞运动、细胞分裂、细胞老化与死亡、线粒体功能维持、胁迫防御反应、物质与能量代谢和信号传导等多种多样的生物学进程。进一步分析这些互作蛋白的生物学功能及与Mopos5的互作机制,对于了解Mopos5可能参与的信号网络及其调控稻瘟病菌在寄主组织内定殖和扩展的分子机制具有重要的意义。 相似文献
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银翘天甘中药制剂抗鸡体内大肠杆菌试验研究 总被引：1，自引：1，他引：0
为观察银翘天甘中药制剂抗鸡体内大肠杆菌的效果,将15日龄雏鸡用O2型大肠杆菌攻毒并开展预防和治疗实验。预防试验是用15日龄雏鸡O2型大肠杆菌攻毒同时口服银翘天甘中药制剂0.5 mL、1.0 mL、2.0 mL,1次/天,连用10天,测定发病率、死亡率和保护率;治疗试验是先用O2型大肠杆菌攻毒并建立疾病模型后口服上述药物,2次/天,连用10天,以头孢噻肟钠作为阳性对照,测定治愈率、有效率和死亡率。预防试验结果表明,银翘天甘中药制剂组实验动物死亡率均极显著低于感染对照组（P<0.01）;中、高剂量组对实验动物的保护率超过85%;在18日龄时,给药组实验动物发病率均极显著低于感染对照组（P<0.01）。治疗试验结果表明：银翘天甘中药制剂实验组感染雏鸡死亡率显著低于头孢噻肟钠阳性对照组（P<0.05）;中、高剂量组治愈率显著高于阳性对照组（P<0.05或P<0.01）,高剂量组有效率显著高于阳性对照组（P<0.05）。由此表明,口服银翘天甘中药制剂能够有效预防和治疗鸡大肠杆菌病。 相似文献
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The origin,evolution, cultivation,dissemination, and diversification of Asian and African rices 总被引：28，自引：0，他引：28
Te-Tzu Chang 《Euphytica》1976,25(1):425-441
Summary Available evidences drawn from biosystematics, evolutionary biology, biogeography, archaeology, history, anthropology, paleo-geology and paleo-meteorology are pooled to reconstruct the series of events that led to the cosmopolitan cultivation of the Asian cultivated rice (O. sativa) and the regionalized planting of the African cultigen (O. glaberrima) in West Africa. The genus Oryza originated in the Gondwanaland continents and, following the fracture of the supercontinent, became widely distributed in the humid tropics of Africa, South America, South and Southeast Asia, and Oceania. The two cultivated species have had a common progenitor in the distant past. Parallel and independent evolutionary processes occurred in Africa and in Asia, following the sequence of: wild perennialwild annualcultivated annual. The weed races also contributed to the differentiation of the cultivated annuals. The corresponding members of the above series are O. longistaminata
Chev. et Roehr., O. barthii
A. Chev., O. glaberrima
Steud., and the stapfii forms of O. glaberrima in Africa; O. rufipogon
Griff., O. nivara
Sharma et Shastry, O. sativa L., and the spontanea forms of O. sativa in Asia.The differentiation and diversification of the annuals in South Asia were accelerated by marked climatic changes following the last glacial age, dispersal of plants over latitude or altitude, human selection, and manipulation of the cultural environment.Cultivation of rice began in many parts of South and Southeast Asia, probably first in Ancient India. Cultural techniques such as puddling and transplanting were first developed in north and central China and later transmitted to Southeast Asia. Wetland culture preceded dryland culture in China, but in hilly areas of Southeast Asia, dryland cultivation is older than lowland culture. The planting method progressed from shifting cultivation to direct sowing in permanent fields, then to transplanting in bunded fields.Widespread dispersal of the Asian cultigen led to the formation of three eco-geographic races (Indica. Sinica or Japonica, and Javanica) and distinct cultural types in monsoon Asia (upland, lowland, and deep water). Varietal types changed readily within the span of a millenium, largely due to cultivators' preferences, socio-religious traditions, and population pressure. Genetic differentiation developed parallel to the ecologic diversification process.The African cultigen developed later than the Asian cultigen and has undergone less diversification. The wild races in South America and Oceania retain their primitive features mainly due to lack of cultivation pressure or dispersal.Both the African and Asian rices are still undergoing evolutionary changes at habitats where the wild, weed, and cultivated races co-exist. 相似文献
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CHRISTOPHER H. WHEELER 《Growth and change》2005,36(3):329-353
ABSTRACT The surge in U.S. wage inequality over the past several decades is now commonly attributed to an increase in the returns paid to skill. Although theories differ with respect to why, specifically, this increase has come about, many agree that it is strongly tied to the increase in the relative supply of skilled (i.e., highly educated) workers in the U.S. labor market. A greater supply of skilled labor, for example, may have induced skill‐biased technological change or generated greater stratification of workers by skill across firms or jobs. Given that metropolitan areas in the U.S. have long possessed more educated populations than non‐metropolitan areas, these theories suggest that the rise in both the returns to skill and wage inequality should have been particularly pronounced in cities. Evidence from the U.S. Census over the period of 1950 to 1990 supports both implications. 相似文献
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David Stuligross 《Asia Pacific viewpoint》2008,49(1):83-97
Abstract: Jharkhand is at the centre of India's struggles to define ‘the environment’ and ‘economically relevant natural resources’. Although cultural labels are applied by leaders who seek influence in these struggles as well as by many of those people who listen, an ethnonational analytic frame does not help answer the questions: How, why and when has the political idea of environment changed in India? When and why has the Jharkhand movement chosen violent tactics? When and why has the Jharkhand statehood movement realised electoral success? Or, why was Jharkhand state formed? To address such questions, a long range historical‐institutional approach is much more fruitful. 相似文献
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Timothy W. Kelsey 《Growth and change》1998,29(3):281-294
This paper explores land use conflicts between non-farm neighbors and farmers to illustrate the usefulness of the concepts of interdependence, rules, and property rights when doing rural development. Recognizing interdependence and its implications helps economic analysis focus on and understand the types of rules and institutions having the most influence on economic behavior, and thus identify policy alternatives. The resolution of land uses conflicts, for example, unavoidably changes the bundle of rights associated with land, andinfluences who can impose costs of whom; it makes a difference if a large farm has the right to produce odors, flies, or noise that reduces their neighbors' abilities to enjoy theneighbors' own land, or if instead, neighbors have the right to use their property without experiencing farm-produced odors, flies or noise the farm may be unable to use its own land for agriculture without being inconvenienced. 相似文献
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Henri L. F. De Groot 《Growth and change》2001,32(1):69-91
This paper develops a two‐sector endogenous growth model with a dual labor market caused by the operation of trade unions. Trade unions strive for the extraction of rents from the growth generating imperfectly competitive primary sector. This union behavior results in a non‐competitive wage differential between the primary and secondary (perfectly competitive) sector. How the relationship between growth and unemployment depends on the institutional details of the labor market is analyzed. In general, growth and unemployment are intimately related for two reasons. Unemployment affects the scale of operation of the economy and thereby the growth rate. Growth affects inter‐temporal decisions of workers about where to allocate on the labor market once they are laid off, and thereby it affects equilibrium unemployment. 相似文献
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Kazuo Watanabe 《Breeding Science》2015,65(1):53-68
Potato has a variety of reproductive uniquenesses besides its clonal propagation by tubers. These traits are controlled by a different kind of genetic control. The reproductive information has been applied to enable interspecific hybridization to enhance valuable traits, such as disease and pest resistances, from the tuber-bearing Solanum gene pool. While progress has been made in potato breeding, many resources have been invested due to the requirements of large populations and long time frame. This is not only due to the general pitfalls in plant breeding, but also due to the complexity of polyploid genetics. Tetraploid genetics is the most prominent aspect associated with potato breeding. Genetic maps and markers have contributed to potato breeding, and genome information further elucidates questions in potato evolution and supports comprehensive potato breeding. Challenges yet remain on recognizing intellectual property rights to breeding and germplasm, and also on regulatory aspects to incorporate modern biotechnology for increasing genetic variation in potato breeding. 相似文献
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不同花生品种氮磷钾钙硫吸收、分配和利用的差异 总被引：1，自引：0，他引：1
通过大田随机区组试验,研究优化施肥条件下,不同花生品种氮磷钾钙硫吸收、分配和利用的差异,旨在为豫南花生产区不同品种花生合理施用氮磷钾钙硫肥提供技术支撑。结果表明,花生仁中氮(N)、磷(P)、硫(S)含量最高,其中,‘驻花1号’的N、‘开农71’的P、‘冀花13’的S含量最高,分别为5.150%、0.558%、0.277%;花生茎叶中钾(K)、钙(Ca)含量最高,其中‘中花16’茎叶中K、‘中花24’茎叶中Ca含量最高,分别为1.637%、0.940%。花生仁中N、P、S积累量最高,其中,‘豫花40’花生仁中N、P、S积累量最高,分别为288.436、25.505、15.263 kg/hm2;花生茎叶中K、Ca积累量最高,其中‘豫花37’、‘中花24’茎叶中K、Ca积累量最高,分别为80.760、54.084 kg/hm2。每形成100 kg荚果需求的N、P2O5、K2O、CaO、S养分量分别3.920~5.042、0.905~1.293、1.626~2.721、0.777~1.150、0.270~0.343 kg。本试验条件下,每形成100 kg荚果,‘豫花22’需求的氮最低,‘中花24’需求的磷最低,‘商花5号’需求的钾、钙、硫最低;‘驻花1号’需求的氮最高,‘开农71’需求的磷、钾、硫最高,‘中花24’需求的钙最高。 相似文献
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旨在为薏苡科学施肥及高产潜力挖掘提供理论依据。以4个薏苡品系为试验材料,于2018—2019年进行大田试验,分析其在不同生育时期氮磷钾(NPK)元素的吸收、分配及利用规律。结果表明,4个薏苡品系的全株总生物量干重在20.5~24.7 t/hm2,地上部分生物产量干重在18.4~22.6 t/hm2之间,但是籽粒产量相对偏低,产量为1969.2~3109.1 kg/hm2。从薏苡抽穗至籽粒成熟,整个植株对NPK元素的吸收和积累量均有增加;N元素在抽穗至扬花期主要分布在茎鞘和叶片,至完全成熟籽粒中N素积累及分配均高于其他部位,而PK元素则主要分配在茎鞘部位。薏苡植株总NPK的吸收量平均为183.93 kg/hm2、62.57 kg/hm2和320.56 kg/hm2,平均吸收比例为N: P: K=2.94: 1: 5.12。薏苡NPK元素的籽粒生产效率和收获指数相对偏低,每100 kg籽粒对NPK养分需求量分别为5.6~7.3 kg,1.7~2.4 kg,8.0~15.0 kg。4个薏苡品系整体物质累积能力强、生物量大,但籽粒对NPK吸收分配和利用效率相对较低,高产潜力的挖掘仍有很大的提升空间。 相似文献