<正>为了培育速生、抗病的桉树杂种，通过苗期病原菌接种和大田试验，对以尾叶桉作母本、细叶桉等8个种作父本的81个桉树种间杂种进行了生长和抗青枯病的联合选择研究。结果表明：尾叶桉与不同父本树种间杂种的存活率介于44.4％尾叶桉×柳桉～74.3％尾叶桉×赤桉；树高、胸径和材积3个生长性状在父本树种间差异不显著，父本树种内杂种间差异达0.05或0.01显著水平；抗病指数在父本树种间和父本树种内杂种间差异均达0.01显著水平；经选择，评选出13个速生、抗病的桉树种间杂种，平均材积为对照母本尾叶桉的自由授粉家系的101.58％～212.65％，平均抗病指数为对照的123.08％～184.60％。

Orthogonal test of supercritical carbon dioxide extraction was carried out to obtain optimum condition as follows: pressure 25MPa, temperature 45℃, time 100 minutes, flow rate of CO2 30kg/h. The yield of volatile oil 1.3163%. GC-MS was used to analyze the components and determine their content. It showed that the main components of volatile oil from Schizonepeta tenuifolia Briq. are pulegone and menthone. However, dihydrojasmone and terrein which had never been reported in surveyed literature have been identified. It was the first time to use two-step separation method to purify the volatile oil from Schizonepeta tenuifolia Briq.. The result showed that by using two-step method, the content of the unsaturated fat acid and its ester from Schizonepeta tenuifolia Briq. decreased effectively. It was also seen that the content of pulegone and menthone increased dramatically compared to one-step method. Therefore, two-step method is a good method for purifying volatile oil from Schizonepeta tenuifolia Briq.. It can be used in industries.