The direct gene transfer systems involved the chemical method (PEG), electroporation, microinjection, particle bombardment, pollen-mediated gene transfer and other systems using various vectors.

In this paper, method of PEG-20M and OV-101 Stainless Capilliary Column on GC-MS is adopted to analyse and study the chemical components of essential oil of Litsea cubeba Pers. in Jiangxi province.

Combining practice engineering, author discusses the construction method and the technique measure of peg to drill hole and to press mortar.