A promoter capable of activating expression specifically in both of the vigorously divisible young tissues and separate-related aging tissues in plants, characterized in that the promoter is a promoter of Oncidium ethylene receptor gene OgERS1, and has a sequence as shown in SEQ ID No: 3. A gene expression cassette is composed of a promoter having a DNA sequence as shown in SEQ ID No: 3, and a polynucleotide that is linked to the 3' terminal of the promoter and has an open reading frame, wherein the promoter can activate the transcription of the polynucleotide in a organism having the gene expression cassette therein. A gene expression vector is composed of a promoter having a DNA sequence as shown in SEQ ID No: 3. A plant or parts of organ, tissue or cell of the plant has been transformed to contain the gene expression cassette described above.