活体染色法观察液泡系

液泡系是细胞内一种重要的细胞器,普遍存在于动植物细胞中,利用活体染色的方法,用低浓度的中性红对大豆种子进行培养并取其根尖进行观察即可看到液泡系的全部演进过程。     

兴安升麻种子休眠和萌发的研究

兴安升麻的种子自然成熟后需要较长的时间才能完成后熟。本研究对兴安升麻的种子进行处理,而后显微观察处理后的胚切片,进而确定打破种子休眠的最佳条件。冷湿处理及外源添加不同浓度的GA3都能不同程度的破除休眠。GA30.5g/L结合低温处理90天,胚有90%以上都处于萌动状态。     

基于文本的本体学习方法研究

本文介绍了当前基于文本的本体学习主要方法,在种子概念的基础上,设计了一种基于文本的本体学习方法,同时分析了术语获取、概念分类、关系获取等基于文本的本体学习关键技术。实验表明,借助种子概念能够从纯文本中抽取概念,对概念进行分类,为本体开发提供基础。     

Educational research for development—Contributions and challenges

Abstract

The study was designed to assess changes in farmers' knowledge of farmer seed production through schools (FSPSs) in Vietnam. A set of 25 questions covering five technical areas of the seed production process was used for pre and post knowledge testing at 12 FSPSs in the provinces Binh Dinh, Nam Dinh, Nghe An and Dong Thap. The main findings show an overall increase in farmer's knowledge scores after attending the FSPS. FSPS-farmers with low scores on the pre-field school test (ex-ante) scored much better on the post field school test. Gender had no effect on the test scores. Binh Dinh province had significantly higher mean scores on the post field (ex-post) school test compared to farmers in Nam Dinh, Nghe An and Dong Thap provinces. The increase in knowledge score is linked to the application of good practices learned in the field school as farmers who applied good quality seeds, low seed rates and the transplanting method showed a large increase in scores. The results of this study indicate that the tests provide insight into the knowledge gaps.     

On the Parable of Weeds and Wheat

This paper probes on one of the famous parables of Jesus-the Wheat and Weeds, and demonstrates some implied meaning and morals connoted in it. Through an interesting contrast between the calm restraint...     

水杨酸浸种对玉米种子萌发及幼苗生长的影响

使用不同浓度的水杨酸溶液对玉米浸种处理,通过测定种子的发芽率、发芽势以及幼苗的一些形态指标和生理指标,研究水杨酸浸种对玉米种子萌发及幼苗生长的影响.结果表明:较低浓度(0.01~0.1mmol/L)的水杨酸处理,可促进玉米种子的萌发与幼苗生长,增加幼苗叶片可溶性蛋白质含量;较高浓度(0.5~1mmol/L)的水杨酸处理,玉米种子萌发与幼苗生长均受到显著的抑制,幼苗叶片中可溶性蛋白质含量显著降低;过高浓度(≥5mmol/L)水杨酸则完全抑制玉米种子萌发.说明0.01~0.1mmol/L水杨酸是处理玉米种子的适宜浓度.     

吡虫啉拌种对冀东地区小麦长管蚜的防效及天敌的影响

为确定药剂拌种对小麦长管蚜的防效及其天敌的影响,以吡虫啉和京东八号为材料进行了实验.结果表明,处理A（拌种药量为1.2g·kg-1,有效成份,以下同）、处理B（拌种药量为0.8 g·kg-1）和ck在小麦整个生育期,麦长管蚜总数分别为4 204,4 128,9 911头·百株-1,且处理A,处理B与ck达到差异显著性（P＜0.05）;处理A和处理B从4月24日到5月25日对小麦长管蚜均具有一定的防效且在5月17日防效达最佳,分别为82.13％,78.11％;经小麦产量分析表明,处理A,处理B,ck的产量分别为0.701 3,0.598 8,0.5644kg·m-2,且处理A与处理B,ck之间达到差异显著性（P＜0.05）;吡虫啉拌种对小麦长管蚜天敌的影响分析表明,处理A和处理B对小麦僵蚜、瓢虫田间数量影响与ck之间达到差异显著性（P＜0.05）.     

杜仲籽中油和杜仲胶的提取工艺研究

为获得长丝杜仲胶,直接以杜仲整籽为原料,对杜仲籽不经粉碎处理。用0.5%氢氧化钠于70℃除去存在于杜仲籽表面的阻挡纤维素酶作用的角质层,然后纤维素酶在pH为4、温度为45℃时破坏籽中的纤维素细胞壁,以提高细胞的通透性,然后先在常温下用石油醚提取杜仲籽油,剩余物质再用石油醚（60~90℃）于80~85℃水浴回流提取杜仲胶,得到了优质长丝杜仲胶。同时,与直接粉碎杜仲籽再用石油醚提取两物质相比,该法油脂得率提高了23%,杜仲胶得率提高了58%。     

Phylogenetic patterns suggest frequent multiple origins of secondary metabolites across the seed-plant ‘tree of life’

To evaluate the phylogenetic patterns of the distribution and evolution of plant secondary metabolites (PSMs), we selected 8 classes of PSMs and mapped them onto an updated phylogenetic tree including 437 families of seed plants. A significant phylogenetic signal was detected in 17 of the 18 tested seed-plant clades for at least 1 of the 8 PSM classes using the D statistic. The phylogenetic signal, nevertheless, indicated weak clustering of PSMs compared to a random distribution across all seed plants. The observed signal suggests strong diversifying selection during seed-plant evolution and/or relatively weak evolutionary constraints on the evolution of PSMs. In the survey of the current phylogenetic distributions of PSMs, we found that multiple origins of PSM biosynthesis due to external selective forces for diverse genetic pathways may have played important roles. In contrast, a single origin of PSMs seems rather uncommon. The distribution patterns for PSMs observed in this study may also be useful in the search for natural compounds for medicinal purposes.     

甘肃小陇山林区橡树籽壳碗叶开发利用前景探讨

通过典型抽样调查,查明甘肃林区主要建群树种橡树的籽壳碗叶的产量;借用已有成果,综合分析提出甘肃林区橡树籽壳碗叶开发利用前景。