减氮施肥对菠菜生长发育及品质的影响

以菠菜为试材,采用随机区组方法,研究尿素不同施肥处理对菠菜生长发育的影响,以期达到菠菜生产合理施肥的目的 .结果 表明:适量的减氮施肥对菠菜植株生长发育及生理指标影响不显著,但过量的减施会显著影响菠菜的株高和产量.随着施氮量的减少,菠菜的维生素C和可溶性糖含量均显著增加.可溶性蛋白质含量有所下降,品种间菠菜硝酸盐含量下降及草酸含量下降,分别达到显著水平.综合比较,以"夏丽"品种在减氮20％处理下效果最佳.     

Effect of Lysine Supplement on the Digestion and Metabolism of the Rumen in Small-tail Han Sheep

5 male Small-tail Han sheep with the body weight of 45 kg at 1.5 years old,fitted with permanent rumen fistula,to study of the effect of the supplement of the untreated commercial lysine on the rumen microbiocoenosis,rumen metabolism and whole body metabolism by 5×5 Latin square design (5 groups:control,control with low urea (equal nitrogen),low lysine,control with high urea (equal nitrogen),high lysine).The amounts of lysine-HCl supplement were 0,4.0 and 8.0 g/kg diet (as DM basis) in each group respectively,with two urea supplement control groups of equal amount of nitrogen.The results showed that by supplement of 4.0 and 8.0 g/kg of lysine-HCl diet (as DM basis) respectively,the voluntary intake of dry matter of sheep were increased by 5.5%(P>0.05) and 11.8%(P<0.05) respectively.The total amount of rumen bacteria were increased by 18.9%(P<0.01) and 23.9%(P<0.01) respectively,as the amount of rumen Coccus was increased by 21.2%(P<0.01) and 30.1%(P<0.01) respectively.The amount of rumen big Bacillus was decreased by 16.7%(P<0.05) and 33.3%(P<0.01) respectively.The total VFA of was increased by 9.6%(P<0.05) and 12.2%(P<0.01) respectively,as the butyric acid was increased by 12.8%(P>0.05) and 20.2%(P<0.01) respectively.The apparent digestibility of organic matter was increased by 6.4%(P>0.05) and 10.0%(P<0.05) respectively,the apparent digestibility of crude protein was increased by 7.0%(P>0.05) and 18.3%(P<0.01) respectively;And nitrogen retention was increased by 46.4%(P>0.05) and 110.7%(P<0.01) respectively.However,there was no effect of lysine supplement on the amounts of the rumen protozoa and fungi,and the concentration of rumen ammonia nitrogen.It was concluded that the supplement of untreated commercial lysine to adult sheep would increase the voluntary intake,digestibility,nitrogen retention the rumen microbiocoenosis and the total amount of rumen bacteria,especially the rumen Coccus of adult sheep.The effect of lysine supplement could not be replaced by urea supplement completely.     

支管射流三通结构优化与试验

为了提高支管射流三通水力性能,改善滴灌的灌水均匀性,基于CFX数值模拟技术,对进口宽度为15 mm的支管射流三通进行结构优化.选取位差、劈距、劈尖半径和侧壁倾角为影响因素,通过四因素三水平正交设计了9组模型,边界条件设定为进口压力100 kPa.选取支管射流三通出口设计流量为评价标准,支管射流三通最优结构尺寸为位差5.5 mm、劈距113 mm、劈尖半径13 mm、侧壁倾角10°.此结构尺寸参数下的支管射流三通水力性能试验结果表明:在进口水压为100 kPa时,支管射流三通脉冲频率为148次/min,水头压力振幅为37.9 kPa,水头压力损失为16.7 kPa,出口流量为0.698 L/s;支管射流三通所接滴灌带长度为60 m时,与普通支管三通相比,支管射流三通的灌水均匀系数提高了2.78%,流量偏差率降低了4.72%.该研究可为射流技术在脉冲滴灌系统的研究、开发与应用提供理论依据.     

农业科技期刊栏目学术影响力的评价—以《热带作物学报》为例

根据中国知网中检索《热带作物学报》2010~2014年发表论文的关键词词频、被引频次、下载频次、论文作者等数据统计栏目篇被引频次、下载频次和影响因子情况，分析农业科技期刊栏目的学术影响力。结果表明：2010~2014年《热带作物学报》文章涉及的主要热带作物为橡胶树、木薯、甘蔗、香蕉、水稻、荔枝、龙眼、芒果和番木瓜等；论文内容涵盖作物营养、栽培与遗传育种，植物生理生化，生物技术与组织培养，作物病虫害及其防治、环境保护，农产品加工与分析检测、综述等6个栏目，其中综述栏目的影响因子最高，发表论文较多的作者文章均属于生物技术栏目。综合上述分析结果，提出了策划精品栏目、加强编辑栏目组稿、针对综述栏目约稿、开辟学术探讨窗口、借助新媒体打造栏目特色等建议，以体现本刊的专业特色和刊物宗旨，将成为读者阅读的向导和作者撰稿的指南。     

核桃枝枯病病原菌鉴定及其生物学特性

In May 2018,a new shoot dieback disease was found in several walnut orchards in Rizhao,Shandong Province.The fungal pathogen was obtained on PDA plate from diseased walnut shoots using a tissue isolation method.The purified fungal isolates formed white to grey colonies on PDA plate and three single spore isolates SDWa1-SDWa3 were obtained.Based on morphological characteristics and analysis of rDNA internal transcribed spacer (ITS),calmodulin (CAL),translation elongation factor 1-α (TEF1) and β-tubulin (TUB) sequences,the fungal isolates were identified as Diaporthe nobilis,a new pathogen on walnut.The test of Koch's rule confirmed that D.nobilis was the pathogen of walnut shoot dieback.To determine optimal growing conditions for the pathogen,its biological characteristics test was conducted.The results showed that the optimal growth temperature and pH value were at 25℃ and pH 5-9,respectively.The optimum carbon source was glucose,and favourable nitrogen source was peptone.     

文心兰HSP70基因的克隆及表达分析

为研究文心兰热激蛋白70基因（命名为OnHSP70）的分子特性及表达特点,以文心兰‘柠檬绿’（Oncidium hybridum ‘Honey Angel’）为材料,采用RT-PCR技术克隆OnHSP70,利用生物信息学方法分析其分子特性,通过qRT-PCR技术分析其在不同组织及不同非生物胁迫处理下的表达特点。生物信息学分析表明：该基因开放阅读框为1944 bp,编码647个氨基酸,翻译的蛋白为稳定蛋白,属于HSP70超家族,其蛋白二级结构由41.11%的α-螺旋、17.77%的延伸链、7.73%的β-转角和33.38%的无规卷曲组成,具有2个高度保守的功能域。聚类分析表明：该蛋白与铁皮石斛和深圳拟兰的HSP70亲缘关系较近。qRT-PCR分析表明：文心兰HSP70在4种不同组织器官中具有表达差异性,在花中的表达量最高;高温处理后基因的表达量明显上升;40 ℃高温胁迫4 h时表达量达峰值;茉莉酸甲酯及水杨酸处理时表达量呈现下调响应。本研究为后期该基因功能研究及提高文心兰对高温的适应性提供理论基础。     

半干旱区农田杂草的生活史对策研究

2008-2009年通过利用当地常见的10种杂草种植于不同处理的农田,研究半干早区农田杂草群落结构以及10种杂草群落组分种对环境因子的响应,结果表明,1)同一物种在不同的气候环境下,可以表现出不同的生活史策略.蝇虫实、田旋花和金荞麦2008年生活史策略分别具有竟争型(C)对策属性、胁迫忍耐型(S)对策属性和中间型(C-...