普通野生稻和药用野生稻种子休眠性的研究

对普通野生稻和药用野生稻种子休眠的原因进行了探讨,表明野生稻种的遗传特性、形态性状、颖壳的透性和种子的生理特性与种子休眠有关。研究结果为打破野生稻种子休眠、提高其发茅力提供了依据和适宜的方法。     

强苯赛对水稻幼苗根系生长的影响

强苯赛浸种对水稻幼苗的根长、根重和根系体积都有促进作用,能提高根尖细胞分裂指数,能使胚根尖切段伸长和发根力增强,并能提高胚乳中淀粉酶活性和根系的呼吸强度。     

民国时期陕西棉麦良种改进的成就与经验

民国时期,陕西大规模引进、培育和推广棉麦良种,成效显著;到1945年,改良棉种植面积已占当年陕西植棉总面积的91%,良种小麦推广面积7年之内扩大100余倍,这不仅使陕西经济获益匪浅,也泽及全国,为抗战胜利做出了贡献。究其原因,一是引进和培育相结合,使良种推广保持在一个较高的水平;二是农事机关具有一定的权威性,能够协调各种组织、机构和农民一道促进良种推广;三是引入市场机制,刺激农民主动按科学方法推广良种。     

基于产业融合的新农村景观生态规划——以重庆种苗科技城为例

在“农业与旅游业”相互融合的前提下对重庆种苗科技城进行调研和论证,提炼出了种苗科技城的“三级形象”规划理念,以生态学理论为基础对种苗科技城进行景观规划,旨在创造新型的基于产业融合的新农村景观,为今后农业园区的建设提供参考.     

棉籽壳价格变动轨迹及其对食用菌生产的影响——基于2010-2012年我国棉籽壳价格分析

分析了2010年1月至2012年2月间我国棉籽壳的价格变动轨迹以及近10年来的棉籽壳供求特征,运用灰色关联法分析棉籽壳价格变动对食用菌市场价格的影响.结果表明：我国棉籽壳价格变动幅度较大;棉籽壳处于供不应求的状态,且这种供求关系在不同地区表现出较大差异;食用菌生产对棉籽壳具有较强的依赖;棉籽壳价格波动对食用菌市场价格具有重要影响.提出了促进我国食用菌产业发展的对策建议：加大科研力度,寻找食用菌基料新配方,降低食用菌生产对棉籽壳依赖程度;建立棉籽壳交易中心,完善棉籽壳交易机制,平抑棉籽壳价格波动,保证棉籽壳供应,提高菇农收入;增加棉籽壳进口,从海外市场寻求棉籽壳供给.     

中国种业开放十余年：回顾与反思

种业对外开放应从两个层面来考察:规则层面的对外开放承诺水平与结果层面的对外开放实现水平。基于以上两方面对种业开放十余年进程的分析表明,我国种业没有开放过度。虽然外资进入的影响更多是冲击和挑战,特别是对我国种业安全甚至粮食安全构成潜在威胁,但是种业对外开放是一个不可逆转的趋势,不能因此而阻止外资的进入。未来种业对外开放政策可在保持总体稳定的前提下,着眼于种业科技发展趋势,同时考虑种业开放带来的双重影响,进行小幅微调。除此之外,种业应对外资冲击与挑战的唯一途径就是做大做强民族种业,加快推进现代农作物种业的发展。     

文化传播与文化增殖——以《泰西新史揽要》在晚清社会的传播为例

在近代"西学东渐"的过程中,<泰西新史揽要>经由西方传教士李提摩太的翻译和广学会的刊印传入晚清社会,一时间举国争诵,"洛阳纸贵".由于其内容上对"变通观"和"进化论"的侧重以及与西方先进的自然科学相结合的特点,这本在西方并不为人看重的历史作品得以在较广范围和较深层次冲击了当时社会的各个方面和各个阶层,特别是对维新派人士产生了不可低估的影响.这一文化传播中的"郢书燕说"现象也揭示了文化增殖的本质.     

田阳敢壮山种子植物区系科的分析

敢壮山位于广西田阳县境内,面积133.3hm2,有野生种子植物254种,隶属于207属、75科,其中世界分布科16个,占总科数的21.3%,热带分布科50个,占66.7%,温带分布科9个,占12.0%,且区域单种科、单属科丰富。生活型以木本为主。区系优势科为蝶形花科、禾本科、菊科、大戟科、桑科等,而表征科是葡萄科、防己科、漆树科、桑科、荨麻科等,它们大多为热带分布科,表明该区系具有热带性质。该区系起源具有古老性,但区系的特有程度较低。     

中小企业核心竞争力的培育和提升

中小企业存在问题的原因是多方面的,有企业外部的原因,比如政府扶持力度不够、融资环境有待改善、市场经济体制的完善尚需时日等,但主要还是由中小企业自身存在的劣势所决定的。以中小企业为目标,从并购、一体多元化、加盟集聚三个方面论述培育和提升其核心竞争力的措施。     

Restoring complex vegetation in urban settings: The case of tidal freshwater marshes

Tidal freshwater marshes have diverse plant communities that vary spatially and temporally due to hydrology, animal activity, and other factors. Development of urban centers along rivers of the U.S. Atlantic coast has reduced the historic extent and quality of these and other coastal wetlands. Because the vegetation of these wetlands is more complex than that of salt and brackish marshes (where restoration of vegetation typical of natural systems has sometimes been successful), restoration of tidal freshwater marsh vegetation is likely to be more difficult, particularly in urban areas. Watershed urbanization alters hydrology, sediment load, propagule availability and composition, nutrient status, and other variables that together create an environment different from that of wetlands in less developed areas, possibly precluding restoration of typical marsh vegetation. Tidal freshwater wetlands were historically extensive along the Anacostia River in Washington, DC, but most of these were lost due to filling, dredging, or hydrologic alteration. Over the last decade, the U.S. Army Corps of Engineers has implemented projects designed to restore tidal freshwater wetlands along the Anacostia, which involved increasing elevation with dredged river sediment and planting native vegetation. To illustrate some of the mechanisms affecting vegetation development in restored tidal freshwater marshes in urban areas, I present a case study on one of these wetlands, Kingman Marsh, that also includes research at another restored wetland and two natural reference sites. Studies by my research groups indicate that the restored wetlands undergo essentially a planting-modified process of primary succession. Low densities of seeds are initially present in the substrate, and prolific seed dispersal into the restored sites results in high initial plant diversity comprised of plantings and ruderal (i.e. weedy) natives and exotics. Seed banks develop rapidly at the restored sites, probably due to colonization and early reproduction by ruderal species. Hydrology and disturbance by non-native animals (including resident Canada goose) are important variables controlling establishment of vegetation in these systems. Recent literature and the case study indicate that the environmental conditions of urban settings impose constraints in restored wetlands that result in plant communities more like those of urban natural wetlands than those of wetlands in less urbanized watersheds. This suggests that rather than design wetland restoration projects with the goal of creating pristine wetland vegetation, restorationists must identify, accept, and if possible capitalize on the ecological constraints of the urban environment in setting achievable and desirable restoration goals.