桑树病虫害的综合防治

桑树病虫害的综合防治,是根据病虫害的发生规律、害虫的生活习性、桑树生长、养蚕季节等,将农业防治、化学防治、生物防治、物理防治、植物检疫等方法结合起来,制定出综合防治措施达到最大的防治效果.亦可在某一季节采用某项措施,同时防治多种病虫害,以节省劳力和药剂,还要考虑到药剂的残效期和对害虫天敌的影响.在生产实践中证明,用单一措施防治病虫害有一定的局限性,而综合防治是主要方向,以获得最大的经济效益和生态效益.     

杨树HSF家族基因生物信息学与胁迫应答表达分析

[目的]探究小黑杨热激转录因子HSF在应答高温和高盐胁迫时发挥的关键作用.保守结构域和顺式作用元件预测等对杨树HSF转录因子家族基因进行生物信息学分析.本研究以小黑杨为材料,经过37℃高温胁迫半个月后观察其形态变化;将小黑杨在37℃下分别处理0、12、24、48 h,采用RT-qPCR对小黑杨组织中的PsnHSFs基因...     

硬质合金刀片切削力控制器的设计及仿真

针对硬态切削条件下的切削力控制问题,建立了控制模型,使用MATLAB/SIMULINK设计了PID/PD控制器,对径向力的控制效果进行了仿真。结果表明:通过调节进给量能够有效地控制径向切削力变化,同时,能够较好地控制刀具的磨损速率。     

省沽油硬枝扦插生根特性

探讨了省沽油1年生硬枝扦插繁殖技术,对影响插穗生根的插穗类型、激素种类、激素质量分数、激素处理时间以及基质种类5个因素进行研究.运用正交试验筛选出扦插最佳组合为A4B4C2D3E4或A4B1C2D3E4,即选择带两对腋芽的下部插穗,用100 mg/kg的NAA或ABT1处理30 min,以蛭石∶草碳=1∶3为基质,进行扦插育苗效果最好,试验处理中最高生根率为73.8%.省沽油硬枝插穗属于综合性生根类型,易生根,根系发达,生根与愈伤组织没有必然联系.     

小兴安岭地区捕食线虫真菌研究初报

从206份带岭的森林土壤样品中,分离出捕食线虫真菌2属5种,分别为:叶状枝节丛孢(Arthrobotrycladodes)、泡环单顶孢(Monacrosporium aphrobrochum)、弯孢节丛孢(Arthrobotry musiformis)、环捕节丛孢(Arthrobotry brochopaga)、少孢节丛孢(Arthrobotry oligospora)。其中,叶状枝节丛孢、泡环单顶孢、弯孢节丛孢、环捕节丛孢为黑龙江省新纪录种。少孢节丛孢(A.oligospora)分布最广、数量最多,为该地区的优势种。大青山顶土壤中捕食线虫真菌的检出率最小,仅为该地区分布的10%。凉水地区18~29林班、14、16林班及9林班50%左右的土样中均有捕食线虫真菌出现,8林班的捕食线虫真菌物种比较丰富,但捕食线虫真菌出现的频率比较低,且产孢量最少。     

Uterine Expression of WNT7A and β-catenin After Induction of Oestrus in Sheep

WNT7A and β-catenin localisations and roles in regulating periimplantation ovine conceptus development under natural estrous conditions have been elaborated.However,their locations and expression patterns have not been reported under induction of oestrus.The localisation,expression and function of WNT7A and β-catenin in the uterine tissues of the early pregnant and non-pregnant sheep on days 10,12,14,16 and 18 following artificial induction of oestrus were investigated by means of in situ hybridisation,real-time RT-PCR,immuno-histochemistry and western blotting methods.WNT7A and β-catenin mRNA and protein were both restricted to the apical surfaces of the uterine luminal epithelium (LE) and glandular epithelium (GE).In pregnant sheep,protein localisation of WNT7A and β-catenin was observed both in the endometrial LE and GE.Their staining presented on day 10,increased between day 12 and day 16,and decreased on day 18.WNT7A and β-catenin mRNA and protein expression increased initially and then decreased from day 10 to day 18,peaking on day 16,and β-catenin reaching a peak on day 18 in the uterine tissues of pregnant sheep (p0.05).By contrast,no significant changes in WNT7A and β-catenin mRNA and protein expression levels were observed from day 10 to day 18 of the oestrus cycle in the uterine tissues of non-pregnant sheep (p0.05).Additionally,WNT7A and β-catenin mRNA and protein expression levels in the uterine tissues of the early pregnant sheep were significantly higher than those of non-pregnant sheep (p0.05).Treatment of endometrial epithelial cells with WNT7A increased the mRNA expressions of β-catenin,c-myc and Cyclin D1.These results provided an underlying mechanism of periimplantation ovine conceptus development under induction of oestrus.     

Multidimensional diversity of bird communities across spatial variation of land cover in Zoige on the eastern Qinghai-Tibetan Plateau

Background: Spatial variation of land cover can result in the changes of community similarities and biotic homog-enization, whereby the increasing similarity wo...