Higher quality RNA could be extracted from the older leaves of simon poplar,the older roots of ehedra,the older leaves of Ammopiptanthus mongolicus and the older roots of Haloxylon ammondendron.

• 以小叶杨的老根、麻黄的老根、沙冬青的老叶、梭梭老根为材料提取出质量比较好的RNA。