平鲉微杯虫的扫描电镜观察

扫描电镜观察平鲉微杯虫（Microcotyle sebastisci Yamaguti，1958）显示：该虫中型个体，具口吸盘1对，口吸盘之间可见口孔，具横隔。口孔正下方为一圆形生殖孔，卵纺锤形具双极丝。后吸器鸡冠状，上面对称排列着两行无柄微杯型吸铗，吸铗形状、大小相近。体表具横向皱褶，背面体表具乳头状乳突，腹面体表密披杆状纤毛。[中国水产科学，2006，13（4）：511—516]     

Blue sucker stock characteristics in the upper Yazoo River basin, Mississippi, USA

Blue sucker Cycleptus elongatus (L.) in the upper Yazoo River basin, Mississippi, USA was studied using overnight hoop net sets (n = 4093) during 1988 and 1990–1998 to determine the influence of channel dredging. There were 264 blue suckers captured, ranging from 3 to 11 years of age. Length ranged from 265 to 700 mm and weight from 120 to 4700 g. Concurrent studies with smaller mesh hoop nets failed to capture any juvenile blue suckers. Catch‐per‐unit‐effort (CPUE: fish net^?1) declined throughout the study in the Yalobusha River, a river subjected to channel dredging during 1988 and 1994. With the exception of limited hydraulic dredging in the Tallahatchie River, there was no dredging in the other Yazoo River tributaries, nor were there declines in blue sucker catch rates in these rivers. Throughout the upper Yazoo River basin, blue sucker stocks were dominated by adult fish, and there was little evidence of reproduction or recruitment. Conservation of the blue sucker in the upper Yazoo River basin should include actions that ensure the functional integrity of this floodplain river ecosystem and elimination of channel dredging throughout the basin.     

台湾脆桃不同类型果枝对产量、果实品质的影响

以台湾脆桃为材料,对不同结果枝类型与产量、果实品质的影响进行相关研究。结果表明,台湾脆桃长果枝数量大、负载能力强,产量上以其为主的特性明显;在适宜粗度范围内,各类果枝类型以分枝角度较小、发育充实、花芽饱满的粗壮结果枝结果性能好、单果重大、可溶性固形物含量高。在栽培上应加强水肥管理培养,修剪时注重选留分枝角度较小、发育充实的粗壮结果枝,以提高产量,增进品质。     

结构用集成材自动上下料装置真空吸附系统设计与试验

针对结构用集成材加工过程中上下料自动化程度低、劳动强度大、效率低等问题,设计了 一种真空海绵吸盘抓取结构用集成材自动上下料装置,实现结构用集成材的高效、自动化上下料作业.选用杉木结构用集成材在自动上下料装置上进行负压与供气压力关系试验和负压与海绵吸盘拉脱力试验.利用MATLAB软件,对试验数据进行最小二乘法函数曲线拟合...     

香蕉花序组织直接诱导芽丛的研究

以香蕉台湾８号的花序为材料，以吸芽为对照，研究了花序组织直接诱导芽丛的培养效果。结果表明：在同等条件下，两种外植体均能直接诱导出芽丛；不同外植体的诱导率，繁殖系数有差异，生根培养及移栽效果基本相同。     

康福多20%浓可溶剂控制大棚温室桃蚜试验

为寻求果品无公害农药 ,对康福多 2 0 %浓可溶剂控制大棚温室桃蚜进行了试验观察。结果表明 ,该药具有广谱、高效、低毒的特点 ,其 70 0 0倍在药后 14d时防效仍高达 94 3%以上 ,堪称目前国内首选的优秀药剂之一。     

电动烟草打顶抑芽机控制系统研究

对一种电动烟草打顶抑芽机的控制系统进行了设计研究。该控制系统的主控芯片为PIC18F13K22,输入信号主要包括剪刀位置信号、喷药量调节信号、电池电压信号和工作开关信号。其中,剪刀位置检测采用霍尔传感器,输出控制信号主要控制电机、电磁阀、蜂鸣器及指示灯,电机采用控制芯片MC33886进行控制。对该机械喷药量的准确性进行了试验测试,验证了机械的精准性,其平均偏差为2.26%。该设计实现了电动烟草打顶抑芽机的半自动化,有效提高了烟草打顶抑芽的工作效率及质量,进一步推动了烟草农业机械化进程。     

Effects of feeding levels on growth performance,feed utilization,body composition and apparent digestibility coefficients of nutrients for juvenile Chinese sucker,Myxocyprinus asiaticus

An experiment was conducted to determine effects of feeding levels on growth performance, feed utilization, nutrient deposition, body composition and apparent digestibility coefficients (ADCs) of nutrients for juvenile Chinese sucker (initial weight, 11.77±0.22 g). Chinese sucker were fed a practical diet from 0% (starvation) to 4.0% (at 0.5% increments) body weight (bw) day^?1 for 8 weeks. The results showed that growth performance, feed utilization, nutrient deposition, body composition and ADCs of dry matter, protein and energy were significantly (P<0.05) affected by feeding levels. Survival was the lowest for the starvation group. Final mean body weight, growth rate, thermal‐unit growth coefficient (TGC) increased with feeding rate from 0% to 3.0% bw day^?1 (P<0.05) and showed no significant differences above the level (P>0.05). Feed conversion rate was significantly lower at a feeding level of 2.5% bw day^?1 than above and below the level (P<0.05). Protein efficiency ratio was markedly highest at the 2.5% bw day^?1 ration level (P<0.05). Fish fed at the feeding level (1.0% bw day^?1), which represented a maintenance ration (energy gain was less than 2.27 kJ fish^?1 day^?1), showed positive protein deposition but negative lipid deposition. This indicates that fish fed a maintenance ration mobilize body lipid reserve to support protein deposition. Lipid contents of whole body, muscle and liver increased with increasing feeding rates from 0.5% to 3.0% bw day^?1 and showed no significant differences above the level (P>0.05). Protein contents of whole‐body composition increased with feeding rate from 0.5 to 3.0% bw day^?1 (P<0.05) and showed no significant differences above the level (P>0.05), whereas muscle and liver remained relatively stable with the different ration amount with the exception of fish fed a ration of 0.5% bw day^?1, at which Chinese sucker possessed significantly lower body protein concentration (P<0.05). The ADCs of dry matter, protein and energy decreased with increasing feeding levels from 0.5% to 3.0% bw day^?1 and then remained relatively constant over the level. Based on the broken‐line regression analysis using WG data, the optimum and maintenance feeding levels for Chinese sucker were 3.10% bw day^?1 and 0.45% bw day^?1 respectively.     

西非布基纳法索共和国道路网干扰对路边环境Pteleopsis suberosa更新的影响

沿铺面道路和未铺面道路,调查了4种路边环境（缓变区,附近区,中间区和非缓变区）的Pteleopsis suberosa苗木种群结构和其更新机制。沿道路平行线调查了2m&#215;5m的203块样方,记录每个样方内的种苗总数和每个种苗的活枝数。通过评价基部和水平枝芽和挖掘地下根系来确定更新机制。结果表明,在4种路边环境中,单一主干和多主干苗木的总密度及各自密度都有明显的变化（p〈0.05）。所有苗木都是无性繁殖而来,根出条占98%,眠芽蘖和萌生各占1%左右。研究表明,铺面道路和未铺面道路缓变区中等水平土壤的干扰可以刺激Pteleopsis suberosa根出条更新 道路类型（铺面和未铺面）对苗木密度没有影响,但对路边立地的P.suberosa种群的萌生能力来说,道路类型是一个重要变量。P.suberosa是一个耐干扰的物种,受道路网干扰后可以通过根出条繁殖。