The quality, purity and quantity of the extracted DNA were assessed by PGENERAL T6 Spectrophotometer (Beijing Purkinje General Instrument Co., Ltd., China). The A260/280 and A260/230 absor- Huang et al. 2729 bance ratios were used to determine the contamination of protein and polyphenolic/polysaccharide compounds, respectively. DNA extracted from all samples were dissolved in 50 μl TE buffer respectively. To evaluate the integrity and compare the productivity of the DNA, gel electrophoresis was carried out by loading 10 μl DNA solution on 1% agarose gel (Invitrogen, California, USA), stained with GoldView (Beijing SBS Genetech Co., Ltd., China), and visualized under UV light with UVP BioImaging system (EC3 system, USA).