Effects of solid matrix priming (SMP) and salt stress on broccoli and cauliflower seed germination and early seedling growth

Abstract

Salt stress affects seed germination and seedling growth. In this study, the effects of solid matrix priming (SMP) and salt stress on broccoli and cauliflower seed germination and early seedling growth were investigated. Physiological and biochemical changes in broccoli and cauliflower seeds and seedlings after the SMP and/or salt stress treatment were determined. Broccoli seeds were primed by mixing the seeds with vermiculite and H2O at a ratio of 1:1.5:2 (w/w/v) followed by two days incubation at 15 °C in the dark. Cauliflower seeds were primed by mixing the seeds with vermiculite and H2O at a ratio of 1:1.5:1 (w/w/v) followed by two days incubation at 20 °C in the dark. The primed and non-primed seeds were air-dried and then germinated on filter papers pre-wetted with H2O containing 0, 50, 100, 150 or 200 mM NaCl. The results showed that, without SMP treatment, the seed germination vigor (GV), germination index (GI) and vitality index (VI) were all inhibited and the mean germination time (MGT) was increased after the treatment with 100, 150 or 200 mM NaCl. The results also showed that the negative effects caused by the salt stress could be alleviated by the SMP treatment. The primed broccoli and cauliflower seeds showed an increase of GV, GI and VI compared with the non-primed seeds under the non-stressed or salt-stressed conditions. In addition, our result showed that the SMP treatment increased the activities of peroxidase and catalase, and the contents of proline, soluble sugar and soluble protein in both broccoli and cauliflower seedlings. We consider that the SMP treatment is useful approach for the improvement of broccoli and cauliflower seed germination and seedling establishment.