Regulation of early flowering in Pinus banksiana

Seedlings of three families of jack pine (Pinus banksiana Lamb.) were subjected to 16 combinations of photoperiod, growth environment (outdoors, greenhouse and biotron) and gibberellin (GA(4/7)) treatment. After 14 months, which included two dormancy induction periods, ovulate flowering was observed. There was a strong positive correlation between flowering and seedling height; female flower production was stimulated by both a declining photoperiod during bud development and GA(4/7) treatment; and there was an interaction between GA(4/7) treatment and family, such that the difference in flowering intensity between a late-flowering and an early-flowering family was eliminated by GA(4/7) treatment. The results suggest that the genetic control over the time of onset of flowering, and GA(4/7)-induction of flowering depend on a common mechanism.     

NUTRIENT CYCLING IN THE DAHURIAN LARCH PLANTATION ECOSYSTEM

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Plantlet regeneration from leaf protoplasts ofPopulus euphratica

Protoplasts were isolated from the leaves of sterile plants ofPopulus euphratica Oliv. by using 1% Cellulase “Onozuka” RS and 0.25% Pectolyase Y-23 in 0.6m of mannitol solution. Protoplasts were cultured in modified Murashige and Skoog's (MS) medium which contained no ammonium ions but was supplemented with BAP (6-benzylaminopurine), 2,4-D (2,4- dichlorophenoxy-acetic acid), and 1% sucrose at the cell density of 9×10⁴/ml. Cell divisions occurred in every culture medium, especially in the medium containing 0.5 mg/l of BAP and 0.1 mg/l of 2,4-D, in which callus was successfully induced by successive culture through cell cluster formation. Shoots were regenerated from the callus, and their growth was enhanced on 1/2 MS medium containing 0.8 mg/l of BAP. Finally, shoots were rooted and plantlets were regenerated on 1/2 MS medium without a hormone. A part of this paper was presented at the 106th Annual Meeting of the Jpn. For. Soc. (1995).     

活性炭载Au-Ru合金作为直接甲酸燃料电池阴极催化剂的研究

研究了活性炭载Au-Ru合金催化剂对氧气还原的电催化性能和抗甲酸性能。通过X射线衍射(XRD)发现原子比为1∶1的Au-Ru/C催化剂中Au与Ru形成合金。通过电化学线性扫描(LSV)测试表明该Au-Ru/C催化剂对氧气还原的电催化性能优于Au/C,Ru/C催化剂,并且发现Au-Ru/C催化剂有很好的抗甲酸性能,可以作为直接甲酸燃料电池(DFAFC)的阴极催化剂。     

不同生境香果树种群的径级结构与分布格局

应用"相邻格子法"对不同生境下的香果树种群进行每木调查,获得野外资料.采用空间代替时间的方法,研究香果树的径级结构和分布格局,以及应用泊松方差/均值比、负二项式分布、Lloyd平均拥挤度指数和聚块指数4个指标分析其种群格局状况.结果表明:不同生境下的香果树径级结构具有较大的相似性--均缺乏幼苗和幼树,种群呈衰退趋势;不同生境下的香果树种群聚块规模为8～32 m2;种群的空间分布格局主要为集群分布;格局动态明显呈现由集群分布到随机分布的扩散趋势.建议采取相应的措施保护母树,尤其是20年生以上的母树;还应加强对种子及幼苗生长动态变化的研究.     

杉木人工林间伐后林下植被生物量的研究

对杉木人工林间伐后林下植被生物量的变化进行测算分析,结果表明,间伐以后,由于林下空间环境因子的变化,植被生物量大量增加,为对照区的3.25倍其中灌木生物量增加273.5％,由对照区占林下植被总生物量的79.78％,提高到91.75％.且灌木种类增多,并尤以层外植物较多.其生物量占灌木生物量的50.25％;草本生物量增加32.49％;林下死地被物生物量达9100kg／hm2,比对照区增加92.80％。     

基于季冻区SMA改性沥青路面早期破损的研究

通过对寒冷地区（如哈同、哈双、哈绥和哈尔滨环城）高速公路SMA改性沥青路面表面状况调查,发现省内该调查路段的SMA路面破损状况的PCI指数超标路段较多,而且裂缝和坑槽也不同程度出现,裂缝开裂间距大小不一,挖方到填方路段间距由小到大,绝大多数路段的车辙和平整度等技术指标衰减较快。通过室外车辙、平整度检测与室内马歇尔试验及抽提试验研究,结果表明：车辙、平整度和坑槽是改性沥青路面早期破坏的主要形式,据此分析研究得出SMA路面早期破损的治理对策。     

活性炭比表面积、孔径对TiO_2/AC光催化活性的影响

以不同孔径和比表面积的系列活性炭(AC)为载体,通过溶胶-凝胶法制备得到TiO2/AC负载型光催化剂。利用氮气吸附、X射线衍射(XRD)、扫描电镜(SEM)对复合催化剂进行表征,并对其进行动态甲苯光降解研究。结果表明:比表面积大、大中孔道丰富的活性炭更适合于负载TiO2制备TiO2/AC复合光催化剂,并且具有更好的光催化活性和延长催化剂的失活时间,对甲苯最大降解率可达97%,失活时间可达11 h,适宜的填充量有利于提高光降解效果。     

厦门市松材线虫病的持续控制技术

为了保住厦门市绿化和美化生态环境的主体树种马尾松,对厦门岛内松材线虫病疫点未采用皆伐寄主松树的方法,而是采取疫情监测、清除枯死松树(枝)、山场套袋化学熏蒸、悬挂松墨天牛诱捕器(捕捉器)、设置立式诱木和释放哈氏肿腿蜂、白僵菌生物防治等持续控制技术,取得了良好的防治效果.发病松林面积由2001年11月首次发现疫情时的1973 hm2减少到2007年的42.8 hm2,病死松树数量由2002年的136968株降低到2007年的6株,病枯死株率呈极显著下降;林间松墨天牛种群数量也大幅度下降,平均每个诱捕器每年诱集到的松墨天牛成虫数量由72.7头下降到1.8头.目前厦门市大面积松林常绿,说明松材线虫病是可防可治的,也为松材线虫病持续控制技术提供了一套行之有效的模式.     

减缓热岛效应的城市规划措施探讨

城市化进程的加剧带来很多城市问题,城市热岛效应就是其中之一.北京作为一个国家性的大都市,城市热岛效应显著.在利用高分辨率遥感影像结合GIS分析技术研究城市道路、水体、绿地对城市热岛效应影响结果的基础上,从城市布局、道路系统规划、能源规划和生态系统规划等方面探讨了减缓城市热岛效应的可能措施.并从北京市的实际情况出发,分析了采用屋顶绿化和开发森林公园等措施来优化城市热环境的可行性.