Search

Pelatantheria scolopendrifolia (Makino) Aver. is a critically endangered orchid species. In this study, an asymbiotic seed germination and development protocol to facilitate in situ and ex situ conservation of P. scolopendrifolia was determined. Seedlings were cultured in vitro on 1/2-strength Murashige & Skoog medium (1/2 MS), Phytamax Orchid Maintenance Medium (POM), Orchid BM1 Terrestrial Seed Germination & Stem Propagation Medium (OBTSG), or Orchid BM2 Terrestrial Stem propagation and Callus Medium (OBTSCM). Seeds started to germinate on all media except POM, with optimal growth on 1/2 MS medium, wherein 70% of seed germinated and produced roots and shoots within 12 weeks. Thus, we recommend culturing P. scolopendrifolia Seeds on 1/2 MS to facilitate germination and seed development, and in turn, in situ and ex situ conservation of this endangered species.

The genus Cypripedium, known as lady's slipper orchid, has been considered to have a considerable marketability as a potted and garden plant with beautiful flowers; however, this species is becoming endangered and, in some places extinct, due to habitat destruction and illegal collections. As such, an optimized artificial propagation system is necessary for its conservation and horticultural cultivation. For the establishment of the in vitro proliferation of the endangered Cypripedium macranthos Sw., native to Korea, the effects of medium strength and sucrose concentrations on germination, protocorm formation and seedling growth were investigated through asymbiotic seed culture. The highest germination rate and protocorm formation rate were obtained with a 1/4 MS medium; higher MS medium strengths did not generate the favorable conditions required for germination and protocorm growth. The overall growth characteristics of roots and buds developed from protocorms were best in cultures of 1/4 MS medium. On this medium containing 10 g·L -1 sucrose, both the germination rate and protocorm formation rate increased significantly. The general growth properties of seedlings developed on the medium with 10 g·L -1 sucrose were best, showing the highest bud formation rate and root number. Our results demonstrate that the 1/4 MS medium, supplemented with 10 g·L -1 sucrose, could improve in vitro germination, and facilitate the growth of seedlings developed from the protocorms of C. macranthos Sw.

The seed morphology and anatomy of 12 species, representing five sections of Thalictrum, were investigated by scanning electron microscopy (SEM) and light microscopy (LM) to evaluate seed features for use in systematic analysis. Considerable differences were observed in seed surface micromorphology and seed coat characteristics both among and within sections of the genus. MANOVA, MDA, and cluster analysis were used to unravel the morphology of seeds among the species. The characteristic seed features for species were found to be seed shape, size, testa thickness, exotestal cells and seed surface sculpture. The results indicated that the most prevalent seed coat sculpture among the studied species was reticulate and some species were reticulate at the margin and rugose in the center. Seed surface was without ornamentation and epidermal cells were mostly polygonal, rectangular or irregularly shaped. The testa thickness varied from two to six cell layers, and the exotesta was well characterized and rectangular to tangentially elongate in most of the species, except T. simplex and T. uchiyamae in which exotesta was poorly represented. It has been observed that species with a non-reticulate or poorly developed reticulate surface sculpture have a less protected seed coat and vice versa. The results of this study indicated that seed morphological features do not, in general, provide strong support to the sectional division of the genus, but that species within sections shared some comparable seed features.