Indole-3-acetic acid biosynthesis in <Emphasis Type="Italic">Aciculosporium take</Emphasis>, a causal agent of witches' broom of bamboo

 Aciculosporium take (Ascomycota; Clavicipitaceae) is a causal agent of witches' broom of bamboo plants. The symptoms of this disease are believed to be induced by plant hormones, particularly auxins. Indole-3-acetic acid (IAA) was identified in cultures of this fungus in an l-tryptophan-supplemented liquid medium. IAA production was confirmed on 30 isolates of A. take from various hosts and locations at levels up to 1 mg/l. The biosynthetic pathway of IAA in A. take culture was examined by analyzing intermediate products and by feeding experiments. The results showed that the indole-3-pyruvic acid pathway (l-tryptophan → indole-3-pyruvic acid → indole acetaldehyde → IAA) was the dominant pathway in A. take. Received: June 3, 2002 / Accepted: July 25, 2002     

Inconspicuous restraint of rice seedling growth by root-infecting fungi in soil of a rice paddy field

 Rice seedling growth, estimated by plant height and root development and discoloration, was better in pasteurized soil than in unpasteurized soil obtained from a flooded rice field. Rice seedlings also grew better in sterilized soil modified by adding roots harvested from the pasteurized soil than in soil modified by adding roots harvested from the unpasteurized soil. The results demonstrate that seedling growth in the rice field soil was inhibited by soil microorganisms, even though no typical symptoms such as seedling blight or damping-off appeared. Pythium aristosporum is suggested to be involved in the inhibition. Thus, it appears that inconspicuous restraint of rice seedling growth could occur in soils of rice paddy fields. Received: May 20, 2002 / Accepted: October 16, 2002 Acknowledgments The authors thank Dr. T. Ichitani, former professor at Osaka Prefectural University, for providing an isolate of Pythium aristosporum for comparison, and Mr. Mitsuaki Sato of Akita Prefectural College of Agriculture for technical assistance.     

贵阳地区小麦白粉菌毒性结构及变异的研究

 的大面积种植抗性很快丧失之后,白粉病的为害日趋严重,已成为我国小麦的主要病害。     

奶牛"两病"的监测与思考

奶牛“两病”是指奶牛的结核病和布鲁氏菌病，是世界动物卫生组织(OIE)规定强制报告的两种疫病，二病都属人畜共患病。人的牛型结核感染主要是通过饮用生奶引起，尤其是儿童常因喝生牛奶被感染而患肠结核杆菌病；饮用生奶或制品也易感染布鲁氏菌病。奶牛“两病”严重威胁着人民的身体健     

稀土元素铈对‘红地球’葡萄组培苗生长的影响

 以‘红地球’葡萄组培苗茎段为外植体，在培养基中添加1～100 mg·L^-1 Ce(NO₃)₃，，研究 不同浓度Ce(NO₃)₃对其生长的影响。结果表明适宜浓度的Ce(NO，)，(1～10 mg·L^-1 )对‘红地球’葡萄组培苗的生长具有促进作用，加快外植体生根，侧根数及侧根总长显著增加,根、茎、叶鲜样质量和干样质量也增加，根系活力提高而增加移栽成活率，增加叶绿素含量，有利于植株对矿质营养的吸收。而100 mg·L^-1。Ce(NO₃)₃对葡萄组培苗生长起明显抑制作用。     

起始肥料对一品红生长的影响

 研究了生长介质中起始肥料对一品红生长的影响和一品红不同部位矿质养分含量。结果表明： 速效肥比缓效肥更有利于一品红生长并提高品质，速效肥中供试的两种NO₃^--N与NH₄⁺-N比例对一品红生长影响不大。绿色叶片矿质养分含量，除Fe和Mn较高外，与国外推荐的养分诊断指标相一致，说明目前国外推荐的一品红养分诊断部位适合于绿色叶片。     

小麦叶锈菌生理小种MFR的分子鉴定研究

 用AFLP方法对来自中国和墨西哥的23个小麦叶锈菌生理小种进行分析,共筛选了64对引物,获得一对引物(M₀₅/E₀₃)可在MFR小种中扩增出一条特异性DNA片段,进行回收、克隆、测序,结果表明该片段具有325个碱基。根据特异性片段序列设计出SCAR标记引物,对60个叶锈菌生理小种分离物进行回检结果表明,研制的SCAR标记能够准确区分MFR生理小种。本实验结果为小麦锈菌生理小种分子检测体系的建立奠定了基础     

菜豆新品种将军油豆的选育

将军油豆是以农家品种大马掌为母本 ,家雀蛋为父本人工杂交后系统选育而成。中熟 ,蔓生 ,从播种到采收 6 5d(天 ) ,生长势强 ,嫩荚绿色 ,扁条形 ,荚尖部有红条纹 ,平均荚长 2 0cm ,荚宽 2 .4cm ,单荚质量 2 4g ,纤维少 ,肉质面 ,属典型的东北优质油豆角类型。抗炭疽病、锈病 ,适应性广 ,春秋皆可种植 ,露地、保护地兼用     

体验经济与内蒙古草原旅游开发

本文通过捕捉近年来消费情况的变化 ,认为应对体验经济引起重视。在介绍体验经济的提出 ,体验的概念和体验的组成部分的基础上 ,提出体验经济对旅游具有创造差异化竞争优势、准确把握市场、使旅游者更舒适愉悦等意义 ,并在体验经济理论下结合内蒙古草原旅游的实际情况 ,提出内蒙古草原的体验设计和营销策略