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21.
纵条纹炭角菌具有镇静、催眠等药用价值,已实现工厂化、规模化栽培。为探究纵条纹炭角菌的研究进展,对其分类学地位、生物学特性、人工培养、化学成分和生理活性等方面的文献进行综述,并提出未来研究的方向和应用前景。  相似文献   
22.
为研究施肥对青稞干物质积累、分配及产量的调节作用,以‘藏青27’、‘QTB13’和‘QTB25’为试验材料,比较分析不同施肥处理下干物质积累、分配及产量的变化规律。结果表明:增加施肥量促进青稞分蘖期—成熟期的干物质积累及开花期和成熟期干物质向营养器官和籽粒的分配,提高了花前营养器官贮藏同化物转运量及对籽粒贡献率,降低了花后同化物输入籽粒量对籽粒贡献率。‘QTB13’和‘QTB25’在F2条件下,更有利于干物质积累及向营养器官和穗部的分配,花后同化物输入籽粒量最大,产量也最大。‘藏青27’在F3条件下,更有利于干物质积累及向营养器官和穗部的分配,花后同化物输入籽粒量和对籽粒贡献率最大,产量也最大。说明合理施肥有利于青稞干物质积累分配及产量提高。  相似文献   
23.
Phytophthora pluvialis and Phytophthora kernoviae are the causal agents of important needle diseases on Pinus radiata in New Zealand. Little is known about the epidemiology of the diseases, making the development of control strategies challenging. To investigate the seasonality and climatic drivers of sporulation, inoculum traps, consisting of pine fascicles floating on water in plastic containers, were exchanged fortnightly at five sites in P. radiata plantations between February 2012 and December 2014. Sections of needle baits were plated onto selective media and growth of Phytophthora pluvialis and P. kernoviae recorded. To explore the generalizability of these data, they were compared to detection data for both pathogens from the New Zealand Forest Health Database (NZFHDB). Further, equivalent analyses on infection of Rhododendron ponticum by P. kernoviae in Cornwall, UK allowed the comparison of the epidemiology of P. kernoviae across different host systems and environments. In New Zealand, inoculum of P. pluvialis and P. kernoviae was detected between January–December and March–November, respectively. Inoculum of both species peaked in abundance in late winter. The probability of detecting P. pluvialis and P. kernoviae was greater at lower temperatures, while the probability of detecting P. pluvialis also increased during periods of wet weather. Similar patterns were observed in NZFHDB data. However, the seasonal pattern of infection by P. kernoviae in the UK was the opposite of that seen for sporulation in New Zealand. Phytophthora kernoviae was likely limited by warmer and drier summers in New Zealand, but by colder winter weather in the UK. These results emphasize the importance of considering both environmental drivers and thresholds in improving our understanding of pathogen epidemiology.  相似文献   
24.
张成林  刘晃  张宇雷 《农业工程》2019,9(10):128-132
在渔业方面,贯彻落实“一带一路”倡议,实施渔业“走出去,引进来”战略,促进我国水产养殖业和周边国家地区的交流合作,共同推动区域传统渔业向现代渔业转型升级,是现代渔业发展的必然方向。泰国作为“一带一路”之东盟国家,从泰国的渔业资源现状、渔业产业发展、渔业现阶段存在的优势和不足以及中泰渔业协作发展探索等多个方面进行阐述,通过研究泰国渔业现状及探索中泰渔业协作发展之路,提出技术支撑、资源引进、取长补短、共同进步等相对应的策略与建议,为中国-东盟国家在基于“一带一路”倡议的渔业层面战略发展提供样本。   相似文献   
25.
Not all economically disadvantaged—“less developed” or “lagging”—regions are the same. They are, however, often bundled together for the purposes of innovation policy design and implementation. This paper attempts to determine whether such bundling is warranted by conducting a regional level investigation for Canada, the United States, on the one hand, and Europe, on the other, to (a) identify the structural and socioeconomic factors that drive patenting in the less developed regions of North America and Europe, respectively; and (b) explore how these factors differ between the two contexts. The empirical analysis, estimated using a mixed‐model approach, reveals that, while there are similarities between the drivers of innovation in North America's and Europe's lagging regions, a number of important differences between the two continents prevail. The analysis also indicates that the territorial processes of innovation in North America's and Europe's less developed regions are more similar to those of their more developed counterparts than to one another.  相似文献   
26.
Increasingly, economies that have traditionally benefited from offshoring are losing some of their strategical advantages, with a consequent increase in backshoring by developed economies. This paper describes the phenomenon and tries to shed light on the current challenges, trends, and debates in the area, and on the main determinants of backshoring. A new phenomenon known as nearshoring is also analysed—this consists of relocating some previously offshored manufacturing activities so that they are now close to previous core locations, but not so close as to suffer from disagglomeration effects. This combines the advantages of offshoring and backshoring.  相似文献   
27.
Most scientific attention on port studies centers on deep sea ports, especially container ports. In this paper, in contrast, attention is focused on the spatial–temporal development of inland waterway ports on the Midstream Yangtze River from 2001 to 2013. The aim of this study is to assess two relevant and complementary questions of the hinterland evolution: its geographical extent and the coordination relationship with the inland port. To conduct the study, it was necessary to first identify the boundaries of the ports' hinterlands within the given timeframe. Then, the coupling coordination degree model was introduced to explore the underlying relationship between the port service and hinterland economy. Furthermore, to better depict the intricate economic characteristics of the hinterland, the development stage theory was applied in the models. The results highlight the emergence of a discontinuous hinterland at Wuhan Port and its reinforcement of primacy with respect to fierce hinterland rivalry. It also demonstrates that an interplay between major ports and their corresponding hinterlands evolves from the transitional stage, characterized by lagging port service, to the multi‐stage, wherein the supply of ports partly outstrips hinterland demand.  相似文献   
28.
A kernel screening assay (KSA) was used to assess the genetic and environmental effects on the vulnerability of maize to aflatoxin accumulation. Kernels of 26 inbred lines that had been grown in seven environments, and 190 lines of the Intermated B73xMo17 (IBM) population grown in one location in the United States, were inoculated with a toxigenic strain of A. flavus and incubated in the dark at 30°C for 6 days. Percent kernel colonization (PKC), sporulation and aflatoxin were influenced by the maize genotypes (G), the location (“ear environment” or E) and the GxE interactions. Overall, low broad‐sense heritabilities were observed for PKC, sporulation and aflatoxin. PKC was significantly correlated with sporulation in all environments. Aflatoxin was positively correlated with colonization for two and with sporulation for all ear environments. Higher grain sulphur or magnesium in IBM was associated with less colonization or aflatoxin. Postharvest susceptibility of maize to aflatoxin is thus influenced by factors that are modulated by the ear environment. In a KSA, sporulation could be a proxy test for aflatoxin accumulation.  相似文献   
29.
St. Augustinegrass is well suited for lawns and commercial landscapes. While many genotypes are cross‐fertile, all cultivars are propagated vegetatively in sod production. To ensure varietal purity, development of sterile triploid hybrids by crossing tetraploid and diploid genotypes has been successfully used in other warm‐season turfgrasses. Applying this model in St. Augustinegrass would be beneficial to sod producers and turf managers who require purity for certification and uniformity for performance, respectively. This study was conducted to develop colchicine‐induced tetraploid lines of St. Augustinegrass. Seeds of cultivar ‘Raleigh’ were treated with four colchicine concentrations at four exposure times. A non‐treated control was included among the treatments. Seedlings that germinated were screened for genome size changes using flow cytometry. Line DSA 13005 and two progeny lines derived through selfing, DSA 16001 and DSA 16016, were corroborated as tetraploids (2n = 4x = 36) through chromosome counts. These lines will be used in future breeding efforts to attempt development of sterile triploid cultivars of St. Augustinegrass.  相似文献   
30.
  目的  探讨五大连池火山山杨叶功能性状特征,揭示植物对火山生境的适应,以及对不同坡向的生存策略,为特殊生境和微地形生境下植物的适应机制提供参考依据。  方法  以5座火山共有植物山杨为对象,测定叶面积(LS)、叶厚度(LT)、比叶面积(SLA)、叶干物质量(LDMC)、叶碳含量(LCC)、叶氮含量(LNC)、叶磷含量(LPC)和叶氮磷比(LNP)等8种功能性状在坡向间、火山间的变化规律和变异特征,分析叶功能性状间相互关系和主成分。  结果  (1)除LCC外,其他7种功能性状在南北坡向间均具有显著差异,LT、LDMC、LNC、LNP表现为南坡大于北坡,而LS、LCC、LPC表现为南坡小于北坡。(2)山杨SLA、LCC、LPC在新、老期火山间差异显著,但在老期火山间差异不显著。(3)火山南坡、北坡山杨LT与LDMC呈显著负相关,南、北坡向及火山间山杨LNP与LNC均呈极显著正相关、与LPC呈极显著的负相关关系。(4)火山环境中山杨LNP、LPC、LNC和LS在叶功能性状分化中起到主要贡献作用。  结论  五大连池火山山杨叶功能性状的变异与火山喷发的特殊性有关,山杨通过调节自身功能性状形成不同的生存策略来适应南、北坡向和不同火山环境,在生长过程中更容易受到氮元素缺乏的限制。火山森林生态系统是一个特殊环境,研究火山植被演替和植物功能性状等问题需要结合火山喷发的特殊情况深入讨论。   相似文献   
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