Study on asymbiotic germination and acclimatization of Paphiopedilum purpureum

Paphiopedilum purpuratum is a nationally class I protected plant species in China, and its seed germination is extremely challenging. To establish an efficient asymbiotic germination system for P. purpureum, capsules were used to investigate the impact of various ages on seed germination, as well as the influence of different organic additives and light intensities on seedling vigor and root development. Additionally, optimal cultivation substrates were screened. The results revealed that seeds with a capsule age of 230 days after pollination (DAP) exhibited the highest germination rate of 80.58% on 1/4 MS medium supplemented with 100 mL of coconut water. In seedling cultivation, the addition of banana was found to effectively enhance crown breadth and root growth, coconut water could effectively facilitate the enlargement of root diameter, whereas the addition of potato significantly promoted the accumulation of soluble sugars and chlorophyll in leaves. High photosynthetic photon flux density (PPFD) of 66.13 µM·M−2·S−1 facilitated crown enlargement, while low PPFD of 4.67 µM·M−2·S−1 was beneficial for root elongation. The optimal cultivation substrate was a 1:1(v/v) mixture of in-situ substrate and limestone, achieving a transplanting survival rate of 75.93%. These findings provide critical insights into establishing an efficient asymbiotic germination system for P. purpuratum, offering technical support for its artificial propagation, and the restoration of the wild population. This study lays a foundation for the conservation and sustainable utilization of this endangered species.