海岛棉愈伤组织诱导及分化的影响因素初探

本研究以新疆自育海岛棉品种新海16无菌苗下胚轴为外植体材料,进行愈伤组织诱导、分化及再生植株的初步研究,筛选出适合于海岛棉体细胞胚胎再生的培养体系。结果表明,最佳诱导愈伤组织及分化配方为MSB附加0.1mg/L2,4-D及0.05mg/LKT,分化率达到88%;于MSB1附加0.01mg/LKT及0.3mg/LNAA中对胚性愈伤组织进行增值培养;由MSB2附加0.1mg/LIBA中可分化出成熟体细胞胚胎及再生植株,分化率达73%。本研究通过体细胞胚胎发生途径获得了海岛棉再生植株,为海岛棉遗传转化体系的建立及分子育种奠定了基础。     

优质中熟杂交早稻汕优45的选育与应用

汕优４５是湖北省咸宁市农科所用珍汕９７Ａ与早籼恢复系４５－１０配组选育而成的籼型杂交早稻新组合。该组合具有产量高、米质优,熟期短,抗病性强等特点,１９９９年３月通过湖北省品种审定。     

复合微生态制剂对蛋种鸡小肠黏膜双糖酶活性的影响

为研究日粮中添加复合微生态制剂对蛋种鸡小肠黏膜双糖酶活性的影响,试验选用1日龄海兰褐蛋种鸡320只,随机分为4个组,试验1、2、3组分别在空白对照组日粮基础上添加50 g/t、100 g/t、200 g/t的复合微生态制剂,分别测定21、42和112日龄蛋种鸡十二指肠、空肠和回肠黏膜中蔗糖酶、乳糖酶和麦芽糖酶的活性。结果显示:①在21和42日龄时,试验2组蛋种鸡十二指肠和空肠黏膜的蔗糖酶活性显著高于对照组(P<0.05);②21和42日龄时,试验组蛋种鸡十二指肠、空肠和回肠黏膜的乳糖酶活性显著高于对照组(P<0.05);③21日龄时,与对照组相比,试验2、3组蛋种鸡空肠黏膜的麦芽糖酶活性显著提高(P<0.05);④42和112日龄时,试验2组空肠黏膜的麦芽糖酶活性都高于对照组(P<0.05)。结果提示日粮中添加复合微生态制剂可提高蛋种鸡小肠黏膜双糖酶活性,在本试验条件下,100 g/t为最适的添加剂量。     

Sulfated beta-glucan derived from oat bran with potent anti-HIV activity

China is a major producer of oats; the annual harvested area of 350,000 ha yields approximately 465,000 tons, giving an average yield of 1.33 tons/ha. The bran is not used for animal feed as it is of poor digestibility and low nutritive content and is considered a waste byproduct. Therefore, it is advantageous to produce a value-added product from the bran. We extracted the native polysaccharide, a linear (1-3)-, (1-4)-linked beta-glucan (OBG) from the oat bran and synthesized a sulfated derivative OBGS containing 36.5% sulfate. OBGS had potent activity against a primary isolate of human immunodeficiency virus (HIV-1) in peripheral blood mononuclear cells at a concentration (EC(50)=5.98 x 10(-4) microM) approximately 15,000 times below its cytotoxic concentration. OBGS was also active postinfection (EC(50)=5.3 x 10(-4) microM) and protected pretreated peripheral mononuclear cells (EC(50)=5.2 x 10(-2) microM) washed free of the compounds prior to infection. Thus, OBGS has potential as a vaginal microbicide and is the first such report for oat bran derived sulfated beta-glucan.     

优质高产晚籼新组合博优258的选育与应用

博优258是广西大学支农开发中心利用自选恢复系测258与不育系博A配组,于1998年晚造育成的感光型晚籼杂交水稻新组合。该组合株高110 cm左右,生长势强,茎杆粗壮,熟期转色好,抗逆性强,全生育期123 d。2000年和2001年参加广西晚造区域试验,结果显示:博优258比对照博优桂99增产3.0%和3.2%,增产效果显著,2003年2月通过广西区农作物品种委员会审定。经多年多点生产试验,博优258表现高产、优质、多抗,产量一般7 500 kg/hm2,高产的达9 750 kg/hm2,至今累计推广面积29.26万hm2,已成为广西晚造主导品种。     

夹指链式残膜回收机脱膜装置设计与试验

针对现有残膜回收机脱膜困难的问题,该研究设计了一种夹指链式残膜回收机脱膜装置,主要由刮板总成、曲柄摇杆机构和膜杂分离机构等组成,可一次性完成脱膜、膜杂分离和输膜作业。为增加夹指随夹指链转过上收膜轮的过程中与刮板接触的次数,将刮板总成中的刮板设为双层,并通过作业过程分析对其结构参数进行设计;使用ADAMS软件对刮板末端运动轨迹进行仿真分析,并根据仿真结果对曲柄摇杆机构的杆件长度及安装角进行设计;通过对残膜受力情况的分析,确定了曲柄摇杆机构的安装位置;通过运动学分析获得了夹指不被漏刮时上收膜轮角速度与曲柄角速度比的最大值;为实现输膜与膜杂分离,设计了往复摆动式膜杂分离机构,并通过作业机理分析及性能试验对相关部件的结构参数进行设计。田间试验结果表明,当机具作业速度为4.5 km/h、刮板宽度为100 mm、曲柄回转中心与上收膜轮中心间的水平安装距离为290 mm、竖直安装距离为200 mm、上收膜轮角速度与曲柄角速度比为0.5、输膜筛相邻棒条间的安装距离为50 mm时,残膜回收率为93.12%,脱膜率为98.2%,含杂率为16.08%,能够满足残膜回收机田间作业要求。研究成果可为相关装置的设计提供参考。     

最小二乘法与SVM组合的林果行间自主导航方法

为了提高作业装备在果园与树林行间的自主导航性能,该研究提出一种基于最小二乘法与支持向量机(SupportVector Machine,SVM)融合的树行识别与导航方法.研究采用履带式小型喷雾机为作业平台,通过低成本的单线激光雷达获取果园或树林环境点云数据,融合姿态传感器进行数据校正,利用最小二乘法拟合识别树行,结合SV...     

How different reforestation approaches affect red soil properties in southern China

Significant differences were found in soil physicochemical and biological effects between various forest restoration approaches of a hilly red‐soil region, southern China. Soil quality was the highest in natural secondary forest (0·95), while in sites revegetated with tea‐oil camellia (Camellia oleifera), Chinese fir (Cunninghamia lanceolata) and slash pine (Pinus elliottii) and control sites, integrated soil quality indices were 0·68, 0·55, 0·36 and 0·04 respectively. The lower soil quality of plantations and controls resulted from increased disruption of soil physical structure, lower quality litter fall, lower litter fall production, reduction in microbial biomass, decline of microbial function and loss of soil nutrients due to periodically artificial tending and accelerated soil erosion. Improvement in soil physicochemical properties and enhanced soil microbial function at a natural secondary forest site demonstrated the inherent restoration of these soils. Hence, natural restoration, as well as reducing human disturbance, is a better approach to improving soil properties than returning farmland to planted woodlands. Copyright © 2005 John Wiley & Sons, Ltd.     

聚光蒸发式太阳能苦咸水淡化系统水体光热性能分析

针对太阳能苦咸水淡化系统中太阳能集热系统在高温段时效率低,而苦咸水淡化系统在低温段时效率低的结构性不匹配问题,提出了聚光蒸发式太阳能苦咸水淡化系统。为了提高苦咸水对入射太阳光的吸收作用,对太阳能集热系统中的苦咸水进行功能化处理,并对功能化苦咸水的透射率进行了光学性能分析,在实际天气条件下,对功能化苦咸水的热能利用效率进行了试验研究。结果表明,功能化苦咸水的透射率随粒子丰度增加而减小,随粒径减小而降低;粒子丰度由6.25增加为50.0 mg/L时,含有粒径为0.72 mm粒子的功能化水体的热能利用效率增加了41.3%;功能化苦咸水热利用效率计算结果与光学性能测试结果变化趋势一致。该研究为提高太阳能苦咸水淡化系统热利用效率提供了参考。