Variation in needle longevity of Pinus tabulaeformis forests at different geographic scales

Needle longevity of conifer species is known to increase with latitude, but little is known about intraspecific variation and associated factors within a location. Chinese pine (Pinus tabulaeformis Carr.) forests were investigated to identify patterns of needle longevity at seven sites with distinctive climatic conditions along a latitudinal gradient (33-38 degrees N) in Shaanxi province, northwest China. A demographic approach was used to quantify needle longevity as an index of entire foliage population adjusted to needle-age-specific mortality rates. There were significant differences in needle longevity of Chinese pine stands across sites and across sample plots within a site. Individual tree needle longevity ranged from 0.62 to 3.75 years for 276 samples across sites. Needle longevity increased with latitude (R2 = 0.40, P < 0.0001), but decreased with mean January temperature (R2 = 0.63, P < 0.0001). Foliage retention of Chinese pine stands at the regional level was generally associated with climatic variability, indicating that variation in needle longevity was primarily an environmental acclimation to low temperature in winter. Stand characteristics were closely associated with needle longevity at three sites located within the same climatic zone. Needle longevity was positively correlated with tree age (R2 = 0.48, P < 0.0001) and stand density (R2 = 0.26, P = 0.0015) at Huanglong and Huangling, respectively, whereas it was negatively associated with total tree height at Zhidan (R2 = 0.50, P < 0.0001). It is concluded that, at the stand and individual tree level, intraspecific variation in needle longevity is most likely a result of adaptation to patchy microsite environments.     

高性能耐磨纸的研究

探索了不同的涂布量、胶粘剂的种类和用量对耐磨纸的耐磨转数、吸水高度和湿强度的影响，通过优化涂布工艺配方使耐磨纸的耐磨转数提高到7000转以上。     

闽东柳杉人工林林分密度控制图的研究

利用闽东地区的柳杉人工林标准地材料研制林分密度控制图 ,经检验精度满足要求。文中还提出一个新的密度效应模型及估计最大密度线参数的方法 ,在生产上有实际应用价值     

油桐根腐病病原菌的研究

油桐根腐病是油桐林的一种毁灭性病害。形态学和培养性状研究表明,致病菌为腐皮镰孢(Fusarium solani(Mart.)Sacc.)。将该菌与国内供试8个腐皮镰孢专化型菌株比较可看出,菌落生长较快,大型分生孢子短而粗,是一种短粗类型。其次,人工接种试验得知,此菌不侵染6科7属7种供试的专化型寄主植物;又经8个专化型菌株接种油桐试验,也不发生侵染关系。此菌仅侵害大戟科油桐属的油桐,是一种专化性病菌。再次,采用聚丙烯酰胺凝胶电泳分析表明,此菌与供试菌株的脂酶同工酶的谱带特征和相对迁移率均有明显的差异。由此,将油桐根腐病鉴定为腐皮镰孢一新的专化型,命名为油桐腐皮镰抱(Fusarium solani (Mart.) Sacc. f.sp.aleuritidis Chen et Xiao f.sp.nov.)     

美国白蛾性信息素在园林上的应用

利用美国白蛾性信息素诱捕美国白蛾可有效监测成虫发生期 ,调查成虫虫口密度 ,为防治下一代白蛾提供准确的防治时间。文章介绍了该诱捕器的使用方法     

浑善达克沙地复合式固沙造林技术分析

复合式造林技术 ,实施后形成带、网、片 ,乔、灌 ,针、阔混交复合式格局 ,变一般固沙型式所形成的单一脆弱植物结构 ,为多样性生物群落 ,使防沙治沙效益向更高层次发展。     

灰花纹鹅膏菌及其生态习性

灰花纹鹅膏菌Amanita fuliginea Hongo的分类地位和生态习性国内一直没有详细报道.用形态解剖、HPLC和种群生态学研究方法对其研究表明日本学者Hongo对该菌的分类是正确的；它的毒素含量与欧洲的主要种毒鹅膏菌Amanita phalloides(Fr.∶Fr.)Link毒素含量相当，甚至更高.湘东湘南丘陵针栎混交林非常适宜该菌生长发育与演化.     

沾益县天然林保护管理地理信息系统建设构想

论述了沾益县天然林保护管理地理信息系统建设的必要性及重要作用，并对该系统建设的软、硬件环境及系统架构、数据传递及更新等方案作了探讨。     

小陇山林区灌丛特点及保护利用初探

以甘肃省小陇山林区为对象，分析论述了该林区灌丛的特点、类型及分布。同时提出了3种保护培育措施和5种利用途径。     

棉籽油及油脚合成汽车涂料固化剂原理的研究

以棉籽油及油脚为原料，经由甲酯化、异构化、聚合及酰胺化等反应，合成了汽车涂料固化剂，探讨了聚合反应的机理，并进行了应用性研究。试验表明，由棉籽油合成的聚酰胺，可以作为汽车电泳涂料固化剂，具有较为广阔的应用前景。