Abstract:

The recent studies of Fokienia hodginsii (Dunn) Henry et Thomas, which is a rare and endangered tree species, show that it can play an important role in the sustainable development of the forest land.So it has been listed as one of the most important tree species in afforestation by the Forestry Ministry of China.A fast, simple and convenient method is established to isolate and characterize the total DNA in fresh leaves, dry leaves and seeds of Fokienia hodginsii.The production rate of these isolated DNA are 150 ~ 250 μg DNA per gram of fresh leaves, 100 ~ 150 μg DNA per gram of dry leaves, 140 ~ 160 μg DNA per gram of seeds respectively, and the rough total DNA OD₂₆₀/OD₂₈₀ =1.80 ±0.02.The total DNA from fresh leaves, seeds and one seed's endosperm is 48 kb respectively, but that fromdry leaves is 50 kb.Therefore, these DNA are all suitable for digesting with restriction enzyme and RAPD analysis, generally the experiment either time is only 4h. It is not necessary to carry on cesium chloride gradient contrifugation and column chromatography or abstraction with chloroform.The rough total DNA can be used in RAPD analysis without RNase digestion, and in digesting with restriction enzyme after being digested by RNase as well. Consequently, it is easy to obtain high yields, high purity and high quality of total DNA in 4h.Especially, the total DNA in dry leaves obtained by this method has a higher level in digesting with restriction enzyme and PCR analysis, thus it solves the inconvenience of drawing materials. During experiment, some useful results have also been found: (1) It has no obvious influence on the isolation of to tal DNA from Fokienia hodginsii whether eliminating chlorophyll before isolation or not. (2) The total DNA can be digested completely only its RNA is eliminated. (3) The RAPD template that has RNA and a certain amount of protein shows no effect on the result of RAPD. (4) DNA templates extracted from fresh leaves, dry leaves or seeds of an individual produce the same RAPD result.

Key words: Fokieniahodginsii, Isolation of total DNA, Extraction medium, Digestion with restriction enzyme, RAPD