珍稀药用植物云南萝芙木种子休眠与萌发特性

Study on the Characteristics of Seed Dormancy and Germination of Rauvolfia yunnanensis(Apocynaceae)

研究了云南萝芙木（Rauvolfia yunnanensis）种子吸水及内源萌发抑制物特性，探讨了赤霉素浓度、温度和光照对种子萌发的影响。结果表明：云南萝芙木新鲜饱满种子28℃和31℃／22℃光照或黑暗下1个月内不萌发，种子胚已分化发育完全，种皮透水，种仁含有萌发抑制物，GA可促进种子萌发，说明云南萝芙木种子具有浅度生理休眠。400-1800mg·L-1是打破云南萝芙木种子休眠的适宜GA处理浓度范围。云南萝芙木种子的适宜萌发温度范围为22～2822和31℃／22℃变温，28％发芽指数最高，1023种子不萌发。云南萝芙木种子在周期性光照和全黑暗下均可萌发，但31℃和31℃／22℃下周期性光照促进种子萌发。

Rauvolfia yunnanensis （Apocynaceae） is known for its medical properties. Its large-scale cultivation is limited due to the limited availability of seedlings. This study investigated the factors that cause seed dormancy by testing the effects of exogenous gibberellin, temperature and illumination upon the germination of R. yunnanensis seeds. The results indicate that fresh mature seeds of R. yunnanensis did not germinate at either 28℃ or 31℃/22℃ （alternating temperature）, whether in light or darkness. The seed coat was water-permeable, but endogenous germination inhibitors were found in the seed kernel. Gibberellic acid （GA） improved germination of R. yunnanensis seeds, indicating that R. yunnanensis seeds have non-deep physiological dormancy. Dormancy breaking of R. yunnanensis seeds can be achieved by applying GA at a concentration of 400-1 800 mg＂ L-1. The suitable temperature range for germination was 22℃-28℃ and 31℃/22℃, while the highest germination success was obtained at 28℃. R. yunnanensis seeds germinated both under continuous dark conditions and alternating light/dark conditions, however, at 31℃ and 31℃/22℃, alternating light/dark conditions improved germination.