<正>采用固相微萃取顶空进样技术和Gc—Ms（气相色谱一质谱）联用技术对金桂、银桂鲜花中的挥发性化学成分进行了对比分析，优选了金桂、银桂香味的采样方法和分析条件（萃取头极性、萃取温度、时间等）。结果表明：利用65斗mPDMs/DVB萃取头萃取后得到的色谱峰较多，两种花中各检出34种化合物。比较发现金桂、银桂鲜花的挥发性物质不但化学组成不同，金桂中特有如β-环柠檬醛，而银桂中特有α，β-二氢-α-紫罗兰酮。而且其相同成分的含量亦有明显的差异，两者含量相差5倍以上，如α-紫罗兰酮和反-β-紫罗兰酮在金桂中的含量为1.74%和1.44%，而在银桂中的含量为0.20%和0.26%；而芳樟醇氧化物等在银桂中的含量明显高于它们在金桂中的含量，两者含量相差5倍以上。

Two hundreds and thirty bacteria were isolated from the leaf of the Pinus massoniana in the Zijinshan and were tested for their nematicidal activity. Eight strains which had nematicidal activity to Bursaphelenchus xylophilus were found. The bacterium JK-JS3 showed the highest nematicidal activity to B. xylophilus. The bacterium cuhure which was diluted 2 times,4 times and 10 times still showed high nematicidal activity to B. xylophilus. After the nematodes were treated with the cultures for 72 h, the lethal rate of the nematodes actained 100%. The nematicidal spectrum of the bacterium JK-JS3 was tested,too. The results showed that the bacterium JK-JS3 had nematicidal activity to all tested nematode strains which included B. xylophilus,B, mucronatus, Panagrellus redivivus,Radopholus similis, Rhabditis sp. and Aphelenchoides besseyi. It was also seen that the nematicidal activity of the bacterium JK-JS3 to different nematode strains was different. The nematicidal activity of the bacterium JK-JS3 to B. xylophilus and Rhabditis sp. was the highest, and the following were B. mucronatus, P. redivivus, R. similis and A. besseyi. The bacteria were classfied by the morphological character and Biolog automated bacterial identification system. It was the Gram-positive bacteria which had peritrichous flagellum and could produce endospore. The bacteria belonged to Bacillus amyloliquefaciens.