Abstract: The experiment used white and blue Saintpqulia ionantha cultivars′ linguoid petal as test materials to determine their pH values of cellular sap and clone F3′5′H gene fragment which was compared with the F3′5′H genes of Solanum tuberosum, Petunia hybrida, gentiana scabra bge, Snapdragon, Pericallis cruentia that were registered in NCBI by using the RT-PCR technique for the study of coloration mechanism. The results indicate that the pH value in blue Saintpqulia ionantha cultivar′ cellular sap was obviously higher than that in white Saintpqulia ionantha cultivar′ cellular sap, and the pH values of two Saintpqulia ionantha cultivars petal cell showed increasing trend, the changes of pH value were greater in white Saintpqulia ionantha cultivar′ cellular sap than those in blue Saintpqulia ionantha cultivar′ cellular sap. And the range of their pH values was between 3.0 and 7.0, which was faintly acid. In two Saintpqulia ionantha cultivars, the cDNA sequence of F3′5′H gene fragment were both 392 bp. Compared with the F3′5′H genes, conservative area of Solanum tuberosum, Petunia hybrida, gentiana scabra bge, Snapdragon, Pericallis cruentia, the homology of nucleotide sequence separately reached 63.0%, 55.4%, 52.8%, 49.0% and 47.7%.

Key words: Saintpaulia ionantha, RT-PCR technology, F3′5′H gene, pH value, flower color