Abstract:

【Objective】 With solid matrix priming (SMP) technique, germination barriers of triploid watermelon seeds were overcome and germination percentage was enhanced by 40%. 【Method】 The investigation of priming mechanism indicated that the water absorbing capacity was slower and not reached saturation of moisture content all the time and rate and the concentration of RNA accumulation increased during SMP process. Using single-seed gel-diffusion assay and electrophoresis method to measure the endo-β-mannanase activity in endosperm envelope of watermelon seeds during imbibition. 【Result】 The result showed that average activity of the endo-β-mannanase and the ratio of seeds with higher enzyme activity in primed seeds were higher than that in control seeds. Investigation of DNA replication levels in primed seeds with flow cytometric determination showed that the 6C:3C ratio in embryonic root tip cells was higher than the unprimed seeds at all stages of seed imbibition. Seed structure inspection with soft-x ray showed that the endosperm envelope of root tip area become thinner in SMP treated seeds. 【Conclusion】 These results indicate that during and after SMP, the influence of seed physiology, DNA replication and seed structure in triploid watermelon seeds have a certain correlation with overcoming germination barriers and enhancement of germination capacity.

Key words: solid matrix priming, triploid watermelon seeds, endo-β-mannanase, flow cytometric determination, soft-X ray