小麦品种慢叶锈抗病性的研究

1982—1984年在温室和田间对3个慢叶锈品种:中引305、中引515、中引709,2个快叶锈品种:无沙八号、纳罗的研究表明,小麦慢叶锈抗病品种具有8个抗病特性:(1)田间发病迟、普遍率增长缓慢,严重率低且发展速度慢;(2)潜伏期较长;(3)侵染频率较低;(4)夏孢子堆较小;(5)菌丝和夏孢子堆面积扩展速度慢;(6)产孢能力较弱;(7)对叶锈菌生理小种特异性不明显;(8)对产量影响不显著。慢叶锈抗病性随植株生长而增强,应用病害发展曲线下面积(AUDPC)的A值比侵染速率r值和冈珀茨方程的k值能更好地表达小麦品种的慢叶锈抗病性。利用温室测定苗期潜伏期、侵染频率和田间发病盛期旗叶的严重率指数可以作为小麦慢叶锈抗病品种的选育指标。     

Conducting carbon wires in ordered, nanometer-sized channels

The encapsulation of graphite-type carbon wires in the regular, 3-nanometer-wide hexagonal channels of the mesoporous host MCM-41 is reported. Acrylonitrile monomers are introduced through vapor or solution transfer and polymerized in the channels with external radical initiators. Pyrolysis of the intrachannel polyacrylonitrile results in filaments whose microwave conductivity is about 10 times that of bulk carbonized polyacrylonitrile. The MCM host plays a key role in ordering the carbon structure, most likely through the parallel alignment of the precursor polymer chains in the channels. The fabrication of stable carbon filaments in ordered, nanometer-sized channels represents an important step toward the development of nanometer electronics.     

Scale of heterogeneity of forage production and winter foraging by elk and bison

The relationship between fine-scale spatial patterns of forage abundance and the feeding patterns of large ungulates is not well known. We compared these patterns for areas grazed in winter by elk and bison in a sagebrush-grassland landscape in northern Yellowstone National Park. At a fine scale, the spatial distribution of mapped feeding stations in 30 m × 30 m sites was found to be random where there were no large patches devoid of vegetation. In areas similar to the mapped sites, the underlying spatial distribution pattern of biomass was also determined to be random. At a broad scale, forage biomass differed among communities across the northern range but forage quality did not. These results suggest that ungulates are feeding randomly within forage patches (fine scale) but may select feeding sites based upon forage abundance at broader, landscape scales. Contrary to what has been suggested in other systems, ungulates were not overmatching at finer scales.     

小麦对条锈病的水平抗病性研究初报

将小麦品种采用随机区组的田间设计种于小种病圃中,以鉴定和测定其水平抗性。根据各个“品种——小种”组合的相对病情指数的方差分析的结果,有些品种,如农大311、西农6028和丰产3号,其品种——小种互作高度显著,被鉴定为具有垂直抗性,另外一些品种,对试验所用的小种并无专化性,并且在大田生产中已显出20多年的持久的中度抗性,初步推测为属水平抗性。在后一类中,有些品种,如平原50,表现为中等反应型,其余则属于呈典型感病的迟锈慢锈类型。在迟锈慢锈品种的病指的对数矫正值(logits)和病圃的锈病强度(以感病对照品种的病指表之)的对数矫正值之间发现了直线回归。     

履带板用高锰钢强韧化研究

本文根据履带板的失效特征和机理,提出了高锰钢的铬、钼再合金化,稀土、钛变质处理和重结晶热处理工艺综合强韧化方案.经实验证实,综合机械性能显著改善.     

早生桑品种育151、育237的育成

采用杂交方法育成早生桑品种育151、育237,具有发芽早、产叶量高,叶质较优、抗黄化型萎缩病较强等特性,发芽期比早青桑捉早2-3天.比湖桑32号早8天左右.产叶量提高6-41%.     

水稻品种对稻褐飞虱抗性的研究

水稻品种对褐飞虱的不同生物型反应是不相同的。试验结果证实:(1)褐飞虱若虫在敏感性品种上的生存率显著地高于抗性品种。在TN_1上,无论那种生物型的生存率均很高;而栖息在Mudgo的褐飞虱若虫,其生存率以生物型2的最高,而生物型1与生物型3的均很低,栖息在ASD_7的若虫,以生物型3的生存率最高。(2)褐飞虱在敏感品种上的后代群体密度显著地比抗性品种的大。生活在敏感品种的若虫,发育进度较抗性品种的快,并且身体较重。(3)在敏感品种取食的飞虱,其分泌的蜜露量较抗性品种的多,生物型2取食Mudgo的和生物型3取食ASD_7的均分泌较多的蜜露。上述结果说明了水稻品种抗褐飞虱的机制属抗生性范畴。     

‘丰香’草莓叶片高效再生体系的建立

 以草莓主栽品种丰香( Fragaria ×ananassa Duch ‘Toyonoka’) 叶片为外植体, 研究了影响组织培养的多个因素, 建立了高效再生体系。结果表明: MS + TDZ 1.5 mg·L ^{- 1} + IBA 0.4 mg·L ^{- 1}培养基最适于不定芽分化。不同滤光膜(绿膜、红膜、蓝膜、黄膜) 对草莓不定芽的分化具显著效应, 绿膜和红膜对芽的分化有明显促进作用, 不定芽再生率达95%以上, 平均每个外植体再生芽数在25个以上; 而蓝膜和黄膜则不利于芽的分化。不同滤光膜光谱差异主要集中在300～700 nm, 红、绿膜在该波段光强较弱,而黄、蓝膜和荧光灯较强。暗处理4周比1、2、3周更有利于提高叶片的不定芽再生率, 此后转到光下培养, 获得的不定芽再生率可达100%。