The relationship between the reduction of nonstructural carbohydrate induced by defoliator and the growth and mortality of trees

Large scale herbivorous insect outbreaks can cause death of regional forests, and the events are expected to be exacerbated with climate change. Mortality of forest and woodland plants would cause a series of serious consequences, such as decrease in vegetation production, shifts in ecosystem structure and function, and transformation of forest function from a net carbon sink into a net carbon source. There is thus a need to better understand the impact of insects on trees. Defoliation by insect pests mainly reduces photosynthesis (source decrease) and increases carbon consumption (sink increase), and hence causes reduction of nonstructural carbohydrate (NSC). When the reduction in NSC reaches to a certain level, trees would die of carbon starvation. External environment and internal compensatory mechanisms can also positively or negatively influence the process of tree death. At present, the research of carbon starvation is a hotspot because the increase of tree mortality globally with climate change, and carbon starvation is considered as one of the dominating physiological mechanisms for explaining tree death. In this study, we reviewed the definition of carbon starvation, and the relationships between the reduction of NSC induced by defoliation and the growth and death of trees, and the relationships among insect outbreaks, leaf loss and climate change. We also presented the potential directions of future studies on insect-caused defoliation and tree mortality.     

蛋白激酶C与细胞增殖调控

介绍了蛋白激酶Ｃ家族的分子结构和基本酶学特征，以及在细胞信号传导、细胞增殖、转化和分化、程序死亡过程中的重要作用，探讨ＰＫＣ研究在临床肿瘤治疗中的意义。     

氟中毒抑制大鼠泌鼠的实验研究

The effect of fluorosis on lactation, lactotroph function and ultrastructure were studied in lactating rats. The results were as follows: 1) Inhibition of lactation in lactating rats with chronic fluorosis was assessed by stunting growth of pups and decrease in the amount of milk suckled by pups in 30 min. Metoclopramide, a blocker of dopamine receptor, could improve lactation in these rats. 2) During chronic fluorosis serum PRL level was decreased, however, PRL content in pituitary was increased. Electronmicroscopic examination showed accumulation of large mature secretory granules and appearance of extremely large abnormal secretory granules in lactotroph cytoplasma. These findings indicate that hormone release of pituitary lactotrophs is obstructed in lactating rats with fluorosis, and the toxic effect of fluoride is mediated by an enhanced function of dopaminergic system in hypothalamus.     

青龙蛇药对眼镜蛇毒中毒动物的保护试验及临床前药理

青龙蛇药是江西省鹰潭市蛇伤防治研究所舒普荣根据多年的临床经验研制的一个复方中草药浸膏剂,经四省一市几家医院的几年临床治疗,对眼镜蛇、五步蛇,蝮蛇、竹叶青蛇、银环蛇、烙铁头蛇等蛇伤中毒病人治疗有显效,治疗效率达99.8％,且毒性低,本文就青龙蛇药对眼镜蛇毒中毒动物机体的保护作用及临床前药理实验的研究结果加以报道,为推广使用和生产本药提供实验数据。材料一、蛇毒:眼镜蛇Najn,naja(Linnaeus)毒由江西省鹰潭市蛇伤防治研究所提供,眼镜蛇毒溶液用生理盐水配制成0.1％母液,贮存于冰箱内保存备用,临用前取母液用生理盐水稀释成所需的浓度。二.动物:小白鼠,体重18—25g,家兔体重2kg左右。二种动物雌雄兼用,实验前禁食12小时但不禁水。     

氟化物对桑蚕幼虫中肠ATP酶活性影响的电镜细胞化学定位

氟化物对桑蚕幼虫中肠ＡＴＰ酶活性影响的电镜细胞化学定位陈玉银,包焕盛,吴玉澄（浙江农业大学杭州３１００Ｎ）桑蚕Ｂｏｍｂｙｘｍｏｒｉ（Ｌ．）氟中毒导致蚕茧严重减产是目前蚕业界最为关切的问题,有关桑蚕幼虫氟中毒的机理研究也从各方面展开［１１］。已知桑蚕氟...     

缺磷或缺铁引起白羽扇豆锰中毒的机理

白羽扇豆在缺磷或缺铁条件下均有排根形成,并且根系还原力显著增加。缺磷、缺铁根系还原力在高峰期分别高于对照。缺磷与缺铁根系还原力高峰不仅出现的时期不同,而且还原力增加部位也不一样。缺磷处理的排根区具有很高的还原力,缺铁处理还原力较高的部位是在主根和侧根的根尖以及排根区。由于Ｍｎ４＋比Ｆｅ３＋更易被还原,致使根系还原力提高促使根际大量锰被还原,这是缺磷和缺铁造成白羽扇豆锰中毒的主要原因之一。     

浅谈生物中毒

浅谈生物中毒徐新荣（江苏省吴江师范学校２１５２００）生物教材中多处提及生物中毒现象。为便于教师在教学中对该类现象作出比较,使学生更好地理解有关中毒机理,懂得一些预防常见生物中毒的知识,本文对此类现象作一介绍。１黄曲霉毒素中毒因贮存不当,花生、米、面等...     

鱼池中一种裸藻水华的研究

鱼池中一种裸藻水华的研究赵玉珩,杨红生,乔志刚,李学军（河南师范大学生物系,新乡４５３００２）ＳＴＵＤＩＥＳＯＮＴＨＥ“ＷＡＴＥＲＢＬＯＯＭ”ＯＦＥＵＧＬＥＮＡＳＰ．ＩＮＦＩＳＨＰＯＮＤＳ￥ＺｈａｏＹｕｈａｎｇ,ＹａｎｇＨｏｎｇｓｈｅｎｇ,ＱｉａｏＺ...