Antibiotic of tetracycline can delay water absorption and germination of Brassica seeds even at low concentrations and it is dependent on seed inherent characteristics.

Processes of seed water absorption and germination are critical for seedling establishment. To investigate the effect of tetracycline (TC), a major-use antibiotic, at low levels (1-5 nM) on the two processes, we selected two sensitive species of Brassica seeds, including Chinese cabbage (Brassica rapa L.) and edible rape (Brassica napus L.), to establish the models of seed water absorption and germination. And every species of the seeds has two cultivars with different initial germination time used for studying. In the experiment at seed water absorption process, results showed that TC retarded the process at ≥ 1 nM, but it depended on seed cultivars for all species. However, the surface structure of seed coat was not related to seed water absorption. In the experiment at seed germination process, results showed that TC delayed the process at ≥ 1 nM, and it depended on seed cultivars for Chinese cabbage but edible rape. Because the longer the duration of the seeds being exposed to TC, the more susceptible the seeds were to TC. Moreover, the results of correlation analysis indicated that the effect of TC on seed water absorption at the early stage would influence that on seed germination at the later stage. It should be paid attention on the negative effects of TC at environmental levels on plants during early development stages which were revealed in our study.