中文摘要：

基于RACE技术，以铁皮石斛叶片总RNA为起始材料，通过逆转录和末端转移构建出两端含有特定序列的cDNA。然后以连接有特定序列的引物进行cDNA的PCR扩增，从而构建出mRNA的cDNA PCR文库。结果表明：cDNAPCR文库的PCR效果明显高于逆转录产物的PCR效果，该方法构建的cDNA PCR文库能使cDNA放大100倍以上；以5pg的总RNA为起始材料构建cDNA PCR文库仍可得到良好的PCR扩增效果；该研究的cDNAPCR文库构建方法费用较低，操作简单，为克隆微量表达的基因提供了技术基础。

英文摘要：

Based on RACE technique,total RNA from Dendrobium candidum leaves was subjected to reverse transcription and terminal deoxynucleotidyl transfer resulting the cDNA which contained the specific sequences in two ends. The obtained cDNA with the specific sequences was amplified using PCR with primers which matched the specific sequencesto establish eDNA PCR library. The results showed that PCR amplification of the cDNA PCR library was more efficient significantly than that of eDNA. The quantity of cDNA was magnified more than one hundred times by the constructed eDNA PCR library. By the eDNA PCR library constructed using 5 pg total RNA as material, the satisfactory PCR amplification results can be obtained. This construction method of the eDNA PCR library was time and labor saving. This method would provided the technical basis for cloning genes of low expression.