Effect of seed cold PEG–priming concentration and period followed by re–drying on germination, growth and flowering of Eustoma grandiflorum （Raf.） Shinn ʻExe Lavenderʼ

This study aimed to investigate whether seed cold priming by PEG‒6000, followed by re‒drying would affect the germination, growth, and flowering of Eustoma ‘Exe Lavender’ raised seedling under high temperatures. Seeds of control treatment were not treated with cold‒priming or re‒drying. In experiment 1, seeds were cold‒primed with water and PEG‒6000 at ‒0.75 and ‒1.5 MPa for 5 weeks at 10°C in the dark and then subjected to re‒dried and storage for 30 days at 10°C. The results showed that cold‒primed seeds germinated earlier than those of the control. Compared to water treatment, plants grown from PEG‒6000 treatments and re‒drying showed similar germination rate, bolting rate, days to bolting, bolting node and flowering rate. In experiment 2, cold priming periods by water and ‒1.5 MPa PEG‒6000 were investigated for 4, 5, 6, 7, and 8 weeks. ‘Exe Lavender’ seeds treated with cold water and in the dark for longer than 5 weeks increased their percentage of radicle emergence and decreased germination rate after 30 days of re‒drying and storage. Meanwhile, those treated with cold-PEG did not protrude the radicle even for 8 weeks of priming and maintained the germination rate after re‒drying and storage. Days to bolting and days to flowering tended to decrease when the priming period decreased. The results suggest that the seed cold priming treatment by ‒1.5 MPa PEG‒6000 and subsequent re‒drying improved germination rate and maintained bolting rate and flowering rate in Eustoma compared to cold priming treatment by water raised seedling under high temperature conditions.

原著論文 (Original paper)