湖北发生的水稻矮缩病是南方水稻黑条矮缩病毒引起的

 近年来由水稻黑条矮缩病毒和南方水稻黑条矮缩病毒引起的水稻黑条矮缩病在华南、华东等地区暴发流行,给水稻生产带来严重损失,而湖北一直未有水稻黑条矮缩病流行的报道。然而,2009年和2010年在湖北省长江沿线的荆州、孝感、咸宁、黄石、鄂州、黄冈等水稻种植区普遍发生水稻矮缩减产的现象。经过症状观察、dsRNA电泳图谱分析、RT-PCR等方法,诊断该病是由南方水稻黑条矮缩病毒引起,说明该病毒已经随介体昆虫白背飞虱从我国南方传播至中部水稻种植区。     

Degradation of chlorophenoxyacid herbicides in aqueous media,using a novel electrochemical method†

The degradation of five chlorophenoxyacid herbicides has been studied using an electrochemical method based on the Fenton reaction (simultaneous reduction of dioxygen and ferric ions). The method consists of electrosynthesizing OH^· radicals, which react rapidly with chlorophenoxyacids in aqueous media. HPLC and GC-MS analysis show the formation of polyhydroxyphenols and quinones in a first step, and the complete destruction of the aromatic nucleus upon exhaustive electrolysis. This offers a possible way for the depollution of natural waters containing chlorophenoxyacid pesticide residues. © 1999 Society of Chemical Industry.     

外源果胶酶对绿茶液微滤过程的效应研究

以膜孔径为0．2μm,膜表面积为0．1m2的SiO2的陶瓷膜对浓度为2％的绿茶液加入外源果胶酶,在温度为35℃,压力为0．3mPa的条件下微滤,研究了外源酶对绿茶液微滤工效、料液品质及微滤过程对外源酶酶促反应的影响。结果表明：加酶微滤的平均膜通量提高30ml／min,终点膜通量提高30ml／min。同时,微滤中的水浸出物、茶多酚、氨基酸、咖啡碱、糖、儿茶素的得率分别提高5．4％、2．2％、1．7％、1．0％、6．2％、10．1％;微滤过程有利于提高外源酶作用效果,微滤后水浸出物、茶多酚、氨基酸、咖啡碱、儿茶素的得率比酶促平衡原料液分别提高9．6％、14．2％、1．1％、6．0％、11．2％。     

修剪时期对核桃伤流及树体生长的影响

核桃树休眠期间修剪伤流严重,为了减少伤流,促进核桃树体生长,在秦岭山区以休眠期修剪为对照,在核桃落叶前、萌芽前及萌芽后进行修剪,监测不同修剪时期对枝条伤流量、剪口枯枝长度、萌芽率、成枝率、枝条生长状况及结果状况等的影响.结果表明:休眠期(对照)修剪的伤流量最大且持续时期最长,且极显著高于萌芽前修剪;与休眠期(对照)相比,3个修剪时期的剪口枯枝长度均显著或极显著减小;落叶前和休眠期(对照)修剪的萌芽率均较高,萌芽前修剪居中,萌芽后修剪的较低;萌芽前修剪的成枝率最高,极显著高于其他3个修剪时期;萌芽前修剪的雌花序数、雌花数、结果数、翌年结果母枝数均高于其他修剪时期,且1年生枝长势最好.综上,推荐秦岭山区核桃在萌芽前15d左右进行修剪,可减少伤流,提高核桃产量,促进枝条生长.     

植物凝集素MNB1基因启动子表达载体的构建及鉴定分析

近年来植物受逆境胁迫的影响日益严峻,而逆境胁迫是造成现代农作物减产的重要因素之一。MNB1基因是拟南芥中与甘露糖高度特异性结合的植物凝集素,具有多种生物学功能,对植物的生长发育及逆境胁迫的应答有着至关重要的调控作用。以拟南芥为试验材料,利用聚合酶链式反应（polymerase chain reaction, PCR）技术成功构建了ProMNB1:GUS植物表达载体,结合浸花法,成功将ProMNB1:GUS载体转化到拟南芥中,最终通过PCR鉴定分析获得ProMNB1:GUS阳性植株,为研究逆境胁迫下MNB1基因的功能及其转录水平的变化提供了重要的依据。     

河西走廊五种禾本科牧草早期耐盐性研究

在实验室对多年生黑麦草、野大麦、无芒雀麦、长穗偃麦草、碱茅种子在0、21、66、110、150、200、267、334、445mmol/LNaCl进行萌发试验。结果表明,除长穗偃麦草以外,种子发芽率随着盐度的增加而降低,胚根、胚芽长及鲜于重则随着盐浓度的增加而减少。种子发芽期耐盐性为长穗偃麦草>无芒雀麦、碱茅>多年生黑麦草>野大麦。在温室条件下,对多年生黑麦草、野大麦、无芒雀麦和长穗偃麦草在0、200、334、445mmol/LNaCl(对应的渗透势分别为0、-0.90、-1.95、-2.603MPa)中的幼苗生长进行研究。结果表明,五周龄时,盐胁迫使地上生物量呈线性降低,而根系生长对盐胁迫没有地上部敏感。以长穗偃麦草最耐盐,野大麦根系耐盐性较强。盐胁迫降低了溶液渗透势造成植物相对水分亏缺,地上部分含水量随着盐胁迫的增加而降低。     

Random Amplification of Polymorphic DNA Fingerprinting of Trypanosoma evansi

The total genomic DNAs from Trypanosoma evansi isolates of bubaline, equine and cameline origin were amplified by polymerase chain reaction using eight arbitrarily selected 10-base primers. Informative band patterns were obtained for all isolates analysed. Depending upon the T. evansi isolate–primer combination, between 1 and 11 reproducible DNA fingerprints of 205 to 3016 bp were amplified, suggesting minor and major differences in their RAPD (random amplified polymorphic DNA) profiles.     

聚合酶链式反应扩增甘蔗钙调蛋白基因及其序列分析

从甘蔗茎顶端分生组织提取点ＲＮＡ,反转录合成ｃＤＮＡ第一条链,以此为模板,参考大麦钙调蛋白基因序列设计并合成５端和３端引物,ＰＣＲ扩增甘蔗钙调蛋白基因,与克隆载体ｐＧＥＭ－３Ｚｆ（＋）重组,转化Ｅ．ｃｏｌｉＨＢ１０１得到得组克隆。ＤＮＡ序列分析结果表明：甘蔗钙调蛋白基因同４５０个核甘酸组成,编码１４８个氨基酸;在核甘酸序列上与迄今知道的几种植物的钙调蛋白基因有很高的同源性,同源率在８０％以上,编码     

大豆短叶柄弱枕性状光温反应及遗传的初步研究

大豆短叶柄突变体ＮＪ９０Ｌ－ １ＳＰ 短叶弱枕性状的表达受光温反应影响较大,当月平均温度达到２４ ．５ ℃,光照长度为１４ ～１５ｈ／ｄ 时,ＮＪ９０Ｌ－ １ＳＰ 植株叶柄表现为短叶柄（ ≤１０ ．０ｃｍ） 弱枕性状（ 叶枕凹状） 。该突变体的短叶柄与弱枕性状之间为完全连锁或一因多效,其受一对隐性或两对隐性重叠基因控制     

Evaluation of the extent of the oxidation reaction during chlorine bleaching of pulp

A modified method was developed to evaluate how much chlorine is consumed by the oxidation reaction during the chlorine bleaching process. This evaluation is, in principle, based on the sum of chloride produced during the chlorination stage (C-stage) and produced during alkali treatment of both the C-stage effluent and the chlorinated pulp. Results obtained by this method proved that about 50%–75% of chlorine was consumed by the oxidation reaction during chlorine bleaching, depending on the reaction condition of chlorination. Even under a reaction condition that is not favorable to an oxidation reaction (low pH), approximately three electrons were abstracted from one lignin structural unit by chlorine bleaching. This result provides additional evidence for our recent observation that lignin is extensively oxidized during chlorine bleaching even when pure chlorine without any chlorine dioxide substitution was used.Part of this paper was presented at the 40th Lignin Symposium. Tsukuba, Japan, October 12, 1995