Abstract
The morphological and morphometric characters of seeds belonging to 11 species of the subtribe Pleurothallidinae using light and scanning electron microscopy were studied to understand the in vitro germination process. Qualitative data (color, shape, ornamentation) and quantitative ones were also evaluated in seeds and embryos (length, width, volume and air space percentage between the integument and the embryo). The viability of the seeds was evaluated by in vitro germination in woody plant medium (WPM), and by analysis of the developmental stages of protocorms until seedling formation (two to 24 weeks). Morphometric data showed variations within the genus Acianthera and between species of different genera. The best germination and protocorm formation responses occurred with Acianthera prolifera (92%) and Acianthera ochreata (86%), with the formation of seedlings after 12 and 16 weeks of sowing, respectively. The seeds and embryos of A. prolifera and A. ochreata were larger (length, width, and volume) with a structural polarity that may have facilitated their germination comparing to others studied species. Other characteristics of A. prolifera seeds that may have contributed to these results include the presence of a thin testa without ornamentation and a suspensor. The protocorms of Anathalis obovata, Dryadella liliputiana, and Octomeria gracillis developed slowly in the WPM, not reaching the seedling stage in 24 weeks of cultivation. This morphological and morphometric study contributes to the understanding of asymbiotic germination of some micro-orchid species.
Highlights
Orchids are suffering from an uncertain future through overexploitation, habitat loss due to human activities and the impact of climate change, and their survival is contingent on a variety of abiotic and biotic factors and their effect on orchid growth, development, and reproduction [1]
Pale yellow seeds were observed in A. prolifera, D. liliputianauana, and S. grandiflora, while the seeds of the other species studied were brown (Table 2)
The ornamentation pattern of the testa cells of some species included papillae or verrucosities (Fig 3N), though these were absent from A. prolifera, A. obovata, S. grandiflora and A. hatschbachii
Summary
Orchids are suffering from an uncertain future through overexploitation, habitat loss due to human activities and the impact of climate change, and their survival is contingent on a variety of abiotic and biotic factors and their effect on orchid growth, development, and reproduction [1]. Their unusual physiology, seed structure, and germination pattern set them apart from other flowering plants.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
