黑龙江省缬草主要分布区种子植物区系分析

黑龙江省有缬草属(Valeriana)4种1变种1变型分布,其主要分布在草甸、沼泽化草甸、次生阔叶林和次生阔叶林林缘内,其主要分布区常见植物有354种,其中种子植物为338种;分析了缬草分布区种子植物组成科、属、种的多样性,以期为缬草种质资源的采集、保护、引种驯化提供依据。     

缬草开发前景广阔

缬草Valeriana属败酱科植物，其药用历史悠久，作为天然镇静解痛剂，毒副作用小，疗效确切；根粉药用，根和根茎提炼的精油可做高级烟草香料、化妆品、食品、保健品和日用品等，国际市场广阔；国内尚无缬草产品问世；黑龙江省产缬草，不仅质量优良而且种质资源潜力大，亟待合理开发。     

东北产缬草属(Valeriana L.)药用植物资源

缬草是败酱科的药用植物。全世界缬草属植物约有200种,我国约有24种。本属植物的根茎及根具有特异香气。其代表种:欧缬草(Valeriana officinalis L.)的根茎及根中含有0.5～2％的挥发油。油中主要成分是异戊酸龙脑酯(bornyl isovalerate),另     

缬草研究进展

介绍了有关缬草的化学成分、生物活性研究及应用研究方面的进展;缬草是很具有开发前途的中草药,值得进一步研究。     

缬草繁殖生物学研究

介绍缬草的两种繁殖方式及其开花、结实、采种等物候学特性,并针对缬草种子休眠,做了种子萌发试验,结果表明:采用变温处理,可使黑水缬草缬草种子萌发率达到86.6%。     

野生黑水缬草和北缬草根精油的分析

阐述了提取野生黑水缬草和北缬草根精油的方法,同时对其精油中所含的化合物进行了分析。     

黑龙江珍宝岛自然保护区春季迁徙水鸟多样性研究

2012年4月10日-5月15日,在黑龙江珍宝岛国家级自然保护区对春迁徙水类多样性进行了调查,共记录到鸟类7目13科45种99567只次。共记录到国家级重点保护鸟类13种26899只。应用鸟类多样性公式对春季水鸟多样性进行了分析,其多样性指数、均匀性指数和物种丰富度指数分别为1.849641、0.336797、和0.00042。并对水域、沼泽、草甸和农田水鸟多样性进行了比较;结果表明其多样性为水域(1.791485)>沼泽(1.789785)>草甸(1.629579)>农田(0.098193);均匀性指数为草甸(0.701821)>沼泽(0.368422)>水域(0.330151)>农田(0.098193);物种丰富度指数为草甸(0.037313)>农田(0.003175)>沼泽(0.000951)>水域(0.00063。本研究为今后水鸟资源管理和濒危物种的保护提供了科学依据。     

中国中部地区发展现代农业的SWOT分析

运用SWOT分析方法,对中国中部地区现代农业发展的优势(strengths)、劣势((weakness)、机会(opportunities)、威胁(threats)进行了分析,构建了一个SWOT矩阵框架,得到了四个策略组合,提出了具体的发展策略,为制定促进中部地区现代农业发展的政策提供了依据。     

不同加工方法对雪峰山天麻主要成分含量的影响研究

本文研究了不同加工方法对天麻主要成分含量的影响.分别采用直接杀青干燥法(A组)、蒸制法(B组)、煮制法(C组)以及糯米合蒸法(D组)4种方法对新鲜天麻进行处理.结果表明,从天麻素和对羟基苯甲醇总值含量来看,A组最高,为(1.606±0.029)％,B组最低,为(0.812±0.225)％,因此直接杀青干燥法最优;从多糖...     

编读往来

告读者为了进一步提升本刊的权威性,我们约请了一些知名学者与权威人士,对“《中国土地》专家指导委员会”成员进行了扩充。这些专家是:陆学艺(中国社会学会会长)、林毅夫(北京大学中国经济研究中心主任)、胡鞍钢(清华大学国情研究中心主任)、樊纲(中国经济体制改革研究基金会秘书长)、李铁(国家发改委小城镇发展研究中心主任)、刘福垣(国家发改委宏观经济研究院副院长)、孙宪忠(中国社会科学院法学所所长)、孙佑海(全国人大环资委法案室主任)、蔡运龙(北京大学土地科学中心主任)、柴强(中国房地产估价师协会秘书长)、叶剑平(中国人民大学土…     

种子产业竞争力分析及发展对策 ———以甘肃酒泉为例

酒泉种子产业发展具有制种自然资源条件优越、普遍掌握制种技术的人才群体、完善的种子产业管理体系、种子质量好以及杂交和常规育种技术等竞争优势,同时存在种子企业数量多但集中度底、基地分散、生物工程新技术弱、营销能力不强等劣势。优质的制种基地、过硬的制种技术等是酒泉种子产业的核心竞争力。只有充分发挥现有优势,以政府为主导,以企业为主体,采取一定措施敦促企业兼并重组;政府、企业互相协作,进一步深化基地建设,建成标准化、规模化制种基地;种子企业、协会、高校及科研单位合作,使种子科研技术高新化;并且企业种子营销创新化,各方保障措施常态化,才能提升产业发展竞争力,提高整个种子产业化水平。     

Farm demand for quality potato seed in Indonesia

Seed is the one of the most costly components of potato production in developing countries. Since potato is a vegetatively reproduced crop, diseases such as viruses build up and yield declines as tubers are saved from one harvest for use as seed the next season. Replacing farm‐saved seed with clean seed is one means to increase yield, but information asymmetry between buyers and sellers on seed quality may restrict market supply of this input. In this article we develop a model of the seed market in which clean seed is treated as a capital good providing benefits over several seasons. To determine farm demand for clean seed, we conducted a survey of 182 potato farmers in the major potato growing areas of Indonesia to elicit their perceptions of seed quality from different sources, and derive farmers' “willingness‐to‐pay” for quality potato seed. Results indicate that the effects of information asymmetry on seed supply may be partially offset by the “reputation” of specialized seed producers. Nevertheless, marginal returns to disease‐free seed appear to significantly exceed marginal costs, indicating that improving supply of quality seed will contribute strongly to productivity growth in potato. We discuss several policy options to encourage supply and utilization of quality potato seed.     

A Case of Mistaken Identity? Measuring Rates of Improved Seed Adoption in Tanzania Using DNA Fingerprinting

Studies of improved seed adoption in developing countries are almost always based on household surveys and are premised on the assumption that farmers can accurately self-report their use of improved seed varieties. However, recent studies suggest that farmers’ reports of seed varieties planted, or even whether the seed is local or improved, are sometimes inconsistent with the DNA fingerprinting results of those crops. We use household survey data from Tanzania to test the alignment between farmer-reported and DNA-identified maize seed types planted. In the sample, 70% of maize seed observations are correctly reported as local or improved, while 16% are type I errors (falsely reported as improved) and 14% are type II errors (falsely reported as local). Type I errors are more likely to have been sourced from other farmers, rather than formal channels. An analysis of input use, including seed, fertiliser, and labour allocations, reveals that farmers tend to treat improved maize differently, depending on whether they correctly perceive it as improved. This suggests that errors in farmers’ seed type awareness may translate into suboptimal management practices. The average yield of seed that is correctly identified as improved is almost 700 kg per hectare greater than that of type I errors. This indicates that investments in farmers’ access to information, seed labelling, and seed system oversight are needed to complement investments in seed variety development.     

Demand for maize hybrids and hybrid change on smallholder farms in Kenya

Kenya is a globally recognized maize “success story.” As the overall percentage of maize farmers growing hybrids tops 80% and the seed industry matures, the slow pace of hybrid replacement on farms, and the continued dominance of the seed industry by Kenya Seed Company, may dampen productivity. Our econometric analysis identifies the factors that explain farmer demand for hybrid seed, and the age of hybrids they grow, considering hybrid seed ownership. Male‐headed households with more education, more assets, and more land plant more hybrid seed. Scale of seed demand per farm is differentiated by agroecology. We find a strong farmer response to the seed‐to‐grain price ratio, which we interpret as evidence of a commercial orientation even on household farms. However, despite the dramatic increase in the number of hybrids sold and the breadth of seed suppliers as seed markets liberalize, an older hybrid still dominates national demand.     

北五味子种子休眠原因初探

为寻找北五味子种子休眠的主要原因,本文通过对种皮透气性、透水性和种内抑制物的测定,并对种胚进行了解剖观察,其结果表明,北五味子种子休眠的主要原因是种胚未完成形态生理后熟和种内存在抑制和脱落酸(ABA)。