现代热带立体农业发展模式的思考

概述了立体农业概念及特点,分析了我国现代热带立体农业发展模式,在此基础上提出了我国现代热带立体农业发展功能及发展对策,为今后热带立体农业的发展提供借鉴。     

我国北方旱作农田保护性耕作发展与展望

保护性耕作是旱地耕作制度的重要组成部分,我国自2002年开始在全国范围内大规模推广保护性耕作。通过少耕、免耕及秸秆还田等综合配套措施,减少农田土壤侵蚀,保护农田生态环境,达到生态、经济效益协调发展的目的。对我国北方旱作农田土壤耕作发展历程、保护性耕作主要成就进行了梳理,并对未来我国北方旱作农田保护性耕作面临的新任务进行了展望,为气候变化条件下旱作农田持续高效发展提供借鉴。     

喹诺酮类药物在渔业的使用现状与发展趋势

喹诺酮是一类合成抗生素类药物,都含有氟原子。其抗菌机理为杀菌型,能穿透细胞壁,深入细胞内部,抑制并阻断细菌的DNA螺旋酶,使DNA复制受阻,细胞不再分裂,导致细菌死亡,从而起到杀菌效果。介绍了喹诺酮类的理化特性及其药物的种类、分子结构和作用机理,检测喹诺酮类药物的常用方法,在渔业的使用现状与发展趋势以及风险评估。     

特色农业发展模式综述

从产业化、区域化和生产要素3个方面探讨了特色农业发展模式,以期为各地选择与其资源禀赋和自身特色相适应的特色农业发展模式提供理论依据。     

Expression of gap junctional connexin proteins in ovine fetal ovaries: effects of maternal diet

Gap junctions have been implicated in the regulation of cellular metabolism and the coordination of cellular functions during growth and differentiation of organs and tissues, and gap junctions play a major role in direct cell-cell communication. Gap junctional channels and connexin (Cx) proteins have been detected in adult ovaries in several species. Furthermore, it has been shown that several environmental factors, including maternal diet, may affect fetal organ growth and function. To determine whether maternal diet affects expression of Cx26, Cx32, Cx37, and Cx43 in fetal ovaries, sheep were fed a maintenance (M) diet with adequate (A) selenium (Se) or high (H) Se levels from 21 d before breeding to day 132 of pregnancy. From day 50 to 132 of pregnancy (tissue collection day), a portion of the ewes from the ASe and HSe groups was fed a restricted (R; 60% of M) diet. Sections of fetal ovaries were immunostained for the presence of Cxs followed by image analysis. All four Cxs were detected, but the distribution pattern differed. Cx26 was immunolocalized in the oocytes from primordial, primary, secondary, and antral follicles; in granulosa and theca layers of secondary and antral follicles; stroma; and blood vessels. Cx32 was in oocytes, granulosa, and theca cells in a portion of antral follicles; Cx37 was on the borders between oocyte and granulosa/cumulus cells of primordial to antral follicles and in endothelium; and Cx43 was on cellular borders in granulosa and theca layers and between oocyte and granulosa/cumulus cells of primordial to antral follicles. Maternal diet affected Cx26 and Cx43 expression, Cx26 in granulosa layer of antral follicles was decreased (P < 0.01) by HSe in the M and R diets, and Cx43 in granulosa layer of primary and granulosa and theca of antral follicles was increased (P < 0.05) by the M diet with HSe. Thus, Cxs may be differentially involved in regulation of fetal ovarian function in sheep. These data emphasize the importance of maternal diet in fetal growth and development.     

陆地棉F2单株结铃数的发育遗传研究

根据数量性状遗传分析的加性-显性发育遗传模型,以6个陆地棉亲本及其按完全双列杂交法配制的15个正交组合F2不同发育阶段的单株结铃数的两年观察值为研究素材,采用MINQUE(1)方法分析了F2单株结铃数在不同发育阶段的遗传动态及其对最终结铃数的影响。试验结果表明,陆地棉F2单株结铃数在结铃早中期具有较大的显性遗传效应,具有较大的杂种优势利用潜力,而在中后期加性遗传效应较强,进行遗传选择效果较好。     

茶尺蠖发育历期的温度效应

观察研究结果表明,茶尺蠖(Ectropis Obliqua Prout)各虫态发育历期随着温度的上升而缩短,发育速率则随着温度的升高而加快,并探明了各虫态历期与期内均温之间的曲线关系模型。同时,用加权法和回归直线法分别计算了各虫态的发育起点温度和有效积温常数,结果表明两种方法计算的数据间差异不显著,表明两方法均可采用。验证结果表明,利用各虫态的发育起点和有效积温,推算茶尺蠖的发生代数及各虫态的发生期,与实际发生情况基本吻合。