人工同龄纯林树冠面积比例系数计算及林分标准密度(立木株数)确定的研究

人工同龄纯林树冠面积比例系数计算及林分标准密度（立木株数）确定的研究熊奎山（甘肃省林业勘察设计研究院兰州７３００２０）关键词人工同龄纯林,树冠面积比例系数,林分标准密度确定Ｒｅｉｎｅｋｅ（１９８３）指出：具有完满立木度的同龄纯林,具有相同的单位面积株...     

兔颈动脉窦和颈动脉体的神经支配

用ＨＲＰ法对兔颈动脉窦和颈动脉体的神经支配进行了分析,表明,支配颈动脉窦和颈动脉体的标记细胞均出现于舌咽神经远节和颈上节。颈动脉体感觉传入中枢突终未见于延髓闩部邻近极后区的腹外侧,颈上节的标记细胞分布于尾侧半部。提示颈动脉窦和颈动脉体对心血在管活动的调节存在着经舌咽神经将感觉传入中枢的通路和经颈上节进行交感神经活动支配的传出通路。为研究心和管生理提供了形态学资料。     

甜菜夜蛾人工饲料研究

在室温26±1℃,相对湿度75％～80％的条件下,分别以3种人工饲料和天然饲料(空心菜叶)对甜菜夜蛾幼虫不同龄期进行饲养比较。结果表明,除1龄幼虫成活率偏低外,3种人工饲料对甜菜夜蛾的发育历期和发育状况与天然饲料基本相似。以黄豆粉为主成分配制的人工饲料饲喂甜菜夜蛾,其化蛹率、蛹重、产卵量和雌雄性比等均优于天然饲料,而且具有配制简便、成本低、不易霉变的特点。通过3代的继代繁殖表明,无论是人工饲料,还是天然饲料,其继代的幼虫成活率和产卵量等均明显下降。     

西方盲走螨保护越冬的研究

引自加利福尼亚的西方盲走螨释放于兰州地区苹果园,由于不能抵御当地1月份低温,未能自然越冬。针对该螨越冬场所:对苹果大树用旧棉絮、麦颖等材料,外围以塑料薄膜包扎枝干;对幼树,采取树冠下地表盖草压土等保护措施,使该螨存活越冬,翌年继续发挥控制李始叶螨的作用。     

果树基因工程研究的现状与展望

利用植物基因工程进行果树遗传改良是一个新的研究领域．研究进展较大，并在10多种果树上获得了转基因植株。本文综述了近年来果树基因工程所取得的进展。但要通过基园工程使果树品种改良走向实用化，还应在提高转化率和植株再生率、果树主要农艺性状遗传分析及转基因的表达和调控等方面作进一步深入研究。     

The disturbance of calcium metabolism of vascular smooth muscle in the late phase of septic shock and the underlying mechanism

AIM: To evaluate the alterations in calcium metabolism of the vascular smooth muscle in the late phase of septic shock and test the hypothesis that nitric oxide might be involved in sepsis-induced vascular hyporeactivity. METHODS: Male Sprague-Dawley rats were subjected to sepsis by cecal ligation and puncture (CLP). 18 hours post CLP, rat aortic rings were employed for measurement of contractile responses by using organ bath technique. RESULTS: In endothelium-denuded aortic rings from CLP rats, concentration-contraction curves to phenylephrine (PE) and KCl were significantly decreased when compared to that from sham control rats. The transient contraction induced by PE in calcium-free Krebs solution and the concentration-dependent contraction to CaCl₂ in KCl-depolarized medium were also markedly reduced. The hyporeactivity was partially reversed by treatment with aminoguanidine, a selective inducible nitric oxide synthase inhibitor. CONCLUSION: An impairment in calcium handling in vascular smooth muscle is involved in the vascular hyporeactivity during the late phase of septic shock, in which an excessive nitric oxide production might be the major mechanism.     

硫酸铜防治绿藻试验

立柱式盆钵水培蔬菜极易滋生绿藻，本试验采用不同浓度的CuSo4溶液控制绿藻的生成和减少绿藻的发生取得了初步成效。试验结果表明，可在大棚生产空闲时期用0.5%CuSO4溶液杀死绿藻，但CuSo4溶液不能作为生产用水以免对蔬菜产生药害。     

PI3-kinase and mitogen-activated protein kinase in cumulus cells mediate EGF-induced meiotic resumption of porcine oocyte

Previous studies have shown that epidermal growth factor (EGF) has the ability to promote in vitro cultured porcine oocyte maturation. However, little is known about the detailed downstream events in EGF-induced meiotic resumption. We designed this study to determine the relationship of EGF, EGFR, phosphatidylinositol 3-kinase (PI3-kinase), MAPK, and germinal vesicle breakdown (GVBD) during oocyte maturation. Our results showed that GVBD in cumulus-enclosed oocytes (CEOs) but not in denuded oocytes (DOs) was induced by EGF in a dose-dependent manner, which indicated that cumulus cells but not oocyte itself were the main target for EGF-induced meiotic resumption. Furthermore, we found that MAPK in cumulus cells rather than in oocyte was activated immediately after EGF administration. To explore whether EGF exerts its functions through MAPK pathway, the activities of EGF receptor (EGFR) and MAPK were inhibited by employing AG1478 and U0126, respectively. Inhibition of MAPK blocked EGF-induced GVBD, whereas inhibition of EGFR prevented MAPK activation. Both AG1478 and U0126 could lead to the failure of EGF-induced GVBD singly. Notably, we found that LY294002, a specific inhibitor of PI3-kinase, effectively inhibited EGF-induced MAPK activation as well as subsequent oocyte meiotic resumption and this inhibition could not be reversed by adding additional EGF. Thus, PI3-kinase-induced MAPK activation in cumulus cells mediated EGF-induced meiotic resumption in porcine CEOs. Together, this study provides evidences demonstrating a linear relationship of EGF/EGFR, PI3-kinase, MAPK and GVBD and presents a relatively definitive mechanism of EGF-induced meiotic resumption of porcine oocyte.