Abstract: To study the varieties and seasonal characters of pollution microflora in plant tissue culture， the pollutant in Hangzhou and Ningbo plant tissue production workshops in Zhejiang province were monitored. The microbes were separated and purified through culturing on the NA and PDA media. The results showed that bacteria and fungi were the major pollutants. Bacteria accounted for 52.13% covering 9 species， and were mainly from the genus Bacillus spp. and Pseudomonas spp. Fungi accounted for 43.87% covering 18 species， and were mainly from Aspergillus niger， Cladosporium spp.， Penicillium spp. and yeast. The total pollutants showed a seasonal change， so did fungal and bacterial contamination ratio in plant tissue production. The peak period of pollutant occurrence was in summer and autumn， while in winter and spring pollution occurred rarely.

Key words: plant tissue culture, pollutant, fungi, bacteria