Abstract

In this study, we focus on the zygote and embryo development process and the seed germination system in vitro of Dendrobium officinale. Two-celled embryo to early globular embryo could be found in seeds collected at 60 days after pollination (DAP). Seeds at 120 DAP were considered to be at the optimal maturity for asymbiotic germination when their embryos reached the late globular stage. Based on the results on embryo development and optimal seed maturity, culture media and organic supplements were tested to improve the seed germination percentage. Modified B5 medium showed the highest germination percentage, followed by culturing in MS and 1/2 MS media. The organic supplements included 200 mL L^–1 potato juice or 100 mL L^–1 coconut juice effectively increased the germination rate and improved the quality of the protocorms. The relationship between the defined process of embryo development and the seed germination in vitro showed that the seeds at 120 DAP in darkness culture condition in the modified B5 medium supplemented with 200 mL L^–1 potato juice was the optimal combination to maximize germination. This study provides knowledge for large-scale industrial seedling production and for the further study of extraction medicinal ingredients from the protocorm of D. officinale.

中文翻译：

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铁皮石斛胚胎发育与种子体外萌发的关系

摘要

本研究重点研究铁皮石斛的受精卵和胚胎发育过程以及种子萌发系统。在授粉后 60 天 (DAP) 收集的种子中可以发现两细胞胚到早期球状胚。当胚胎达到晚期球形阶段时，120 DAP 的种子被认为处于非共生萌发的最佳成熟度。根据胚胎发育和最佳种子成熟度的结果，对培养基和有机补充剂进行了测试，以提高种子发芽率。改良的 B5 培养基显示出最高的发芽率，其次是在 MS 和 1/2 MS 培养基中培养。有机补充剂包括200 mL·L ^-1马铃薯汁或100 mL·L ^-1椰子汁，有效提高了发芽率并改善了原球茎的质量。确定的胚胎发育过程与种子体外萌发之间的关系表明，在改良B5培养基中添加200 mL L ^–1马铃薯汁的种子在120 DAP黑暗培养条件下是最大化萌发的最佳组合。本研究为大规模工业化种苗生产以及进一步研究铁皮石斛原球茎药用成分的提取提供了知识。