北部高寒区大豆化学除草药害产生原因分析

北部高寒区常用除草剂产生药害的原因,一是受天气环境、土壤有机质、土壤残留、飘移、沾染等自然环境的影响;二是使用技术即人为的作业不标准、施用时期、混配技术、浓度过量、误导与误用;三是除草剂本身成份决定的如选择性不强、质量问题。     

硒对不同类型杂交水稻品种发芽特性的影响

通过种子萌发试验,研究不同浓度硒对海南省50个杂交水稻品种种子萌发和幼苗生长的影响,并对所有参试品种进行分类。结果表明:不同浓度硒处理对水稻种子发芽率、发芽势、幼苗最长苗长和幼苗鲜重值均具有一定的影响。即低浓度硒(0.2mg/kg)对种子萌发具有一定的促进作用,随着浓度的增大,促进作用逐渐变弱,且当浓度为12mg/kg时,外源硒在一定程度上抑制了上述四项指标。最长根长随着外界硒处理浓度的增加,而不断下降。根据在浓度为5mg/kg硒作用下发芽率,发芽势,最长根长,最长苗长和幼苗鲜重的胁迫指数,将50个杂交水稻品种分为三大类:耐受型(3个品种)、中间型(24个品种)和敏感型(23个品种)。与中间型和抑制型品种相比,耐受型水稻品种的种子萌发在5mg/kg外界硒作用下,具有较强的促进作用,且幼苗最长苗长、根长和苗重所受该浓度硒抑制作用较小;抑制型品种的种子萌发在5mg/kg的外源硒作用下开始受到轻微的抑制作用,且与耐受型和中间型品种相比,幼苗最长苗长、苗鲜重、最长根长也受到最大强度的抑制作用;中间型品种五项发芽指标指数居于耐受型和抑制型品种之间。耐受型中的品种捷丰优629在浓度为5mg/kg硒处理下,与其它参试品种相比,呈现出最强的耐硒性,且在外界硒胁迫作用下,仍然具有较好的发芽率、发芽势等发芽特性。     

海藻酮糖液的制备

以异麦芽酮糖母液为原料,利用模拟移动床分离母液中的海藻酮糖和异麦芽酮糖,制备海藻酮糖液。选用漂莱特钙型色谱分离型树脂作为分离剂,去离子水为洗脱剂,在合适的中试条件下实现了海藻酮糖和异麦芽酮糖的有效分离。模拟移动床海藻酮糖和异麦芽酮糖出口产品纯度分别为70.96%和53.08%。     

香蕉的价值

香蕉全身都是宝。本文从香蕉的经济价值、遗传学研究价值、营养价值及应用价值等方面对香蕉的价值进行了综述。     

The importance of APC

Readers in immunology are familiar with the importance of antigen presenting cells in mounting immune responses. For the purpose of this particular editorial article, however, the abbreviation APC will stand for article processing charges. The publisher will introduce APCs for this Journal in May, 2005. Here we explain why article-processing charges are important to maintain our Open Access journal.     

The utilization of rainfall

American Journal of Potato Research -     

The Relevance of Rice

Research into rice—the world’s most important food crop—is crucial for the development of technologies that will increase productivity for farmers who rely on rice for their livelihood. This is particularly the case throughout the developing countries of Asia and is also true for much of Latin America and, increasingly, Africa. The benefits of such increased productivity will flow through to rice-growing countries’ landless rural and urban poor, all of whom (1) are net consumers of rice and (2) spend a large proportion of their income on rice. Recent steep rises in the price of rice have amplified the need for investment in high-quality research targeted toward both the intensive irrigated rice-based systems (in which 75% of the world’s rice is grown and that must provide the rice for rapidly increasing urban populations) and the rainfed rice-based systems (many of which are characterized by unfavorable environments and extreme poverty).     

稻米的脂肪

本文综述了稻米中脂肪的种类及与品质和陈化的关系,讨论了利用分子标记辅助选择技术和转基因技术手段改良稻米中脂肪含量的前景.     

温度对暴马丁香中齐墩果酸提取的影响

为了保护和有效利用暴马丁香资源,本实验探究温度对超声波提取暴马丁香中齐墩果酸的影响。结果表明:在提取条件为液料比20:1、70%的乙醇,超声功率为300W、超声30min时,超声温度为50℃时提取效果最佳,含量达2.9993%。可供暴马丁香中齐墩果酸的提取工艺提供参考。     

The study of shea butter. VI: The extraction of shea butter

Shea butter has been extracted from the seeds of the shea tree,B. parkii, with various organic solvents. Petroleum ether (40°–60°C),n-hexane, chloroform, and benzene extracted 32%–38% of fat and 8–9 mg% of vitamin E. These solvents, particularly petroleum ether andn-hexane, can be used for the production of shea butter that is free from any oxidized fat and coloring impurities.