Self-pollination of the orchid Cycnoches haagii from Brazilian Cerrado results in albino phenotype seedlings

Vespasiano Borges De Paiva Neto,Jerônimo Constantino Borel,Mateus De Aguiar Torrezan,Monica Cristina Rezende Zuffo-Borges,Daly Roxana Castro Padilha,Manoela Aparecida Vieira Da Silva

doi:10.1590/2447-536x.v28i1.2411

Abstract

Abstract Cycnoches haagii Barb. Rodr. is an epiphytic orchid very targeted by collectors, but no reference was found in the literature about its reproductive biology. Thus, the purpose of this study was to obtain initial information regarding pollination types and its influence on seed viability of this native orchid of the Brazilian Cerrado, in order to enable future propagation and preservation programs. Pollination among flowers of the same plant (geitonogamy) or different plants (xenogamy) were carried out. Seeds extracted from the capsules were sown in B&G medium, with full and half strength. Seeds from geitonogamic resulted in 25% of albino protocorms and consequently in albino seedlings. This phenomenon did not occur in seedlings derived from xenogamic pollination. Pigment analysis showed that even the albino seedlings presented chlorophylls and carotenoids, however, in significantly minor concentrations, 16% and 37% respectively, in relation to green seedlings. Geitonogamic and xenogamic pollinations resulted in C. haagii viable seeds with high germination percentage (90%) under in vitro conditions. The germination of seeds from xenogamic pollination resulted in chlorophyll or normal seedlings only, and can be recommended at conservation programs. On the other hand, although geitonogamic pollination should be avoided at conservation programs of this orchid species as it leads to albino seedlings, it showed a very interesting system to obtain seedlings with this phenotype, an interesting plant material to future investigation.

Highlights

Orchidaceae is one of the largest plant families, containing more than 25,000 species in the entire world (Chase et al, 2015), but it is among the most threatened of all flowering plants (Huang et al, 2018).Cycnoches haagii Barb
No statistical difference was found in the germination percentage of seeds originated from both pollination processes, independent of the medium strength, resulting in mean values around 90.0%
This germination rate was higher than the 78.4% obtained by Torrezan et al (2018), under asymbiotic conditions in B&G medium, but using seeds resulted from natural pollination, resulting in protocorms and seedlings with normal phenotype or green phenotype

Summary

Introduction

Orchidaceae is one of the largest plant families, containing more than 25,000 species in the entire world (Chase et al, 2015), but it is among the most threatened of all flowering plants (Huang et al, 2018).Cycnoches haagii Barb. Is an epiphytic and not endemic orchid native to the Cerrado Domain, being found in different vegetation formations in the Brazilian states of Amazonas, Pará, Rondônia, Goiás and Mato Grosso (Barros et al, 2015). Rica (Barros et al, 2018) As it is a species with high ornamental potential (Torrezan et al, 2018), and given the beauty and delightful smell of the flowers, as well as the magnitude of the vegetative structures, these authors affirm that studies on the propagation process of this orchid are essential, to improve the production process making it economically viable, and to preserve, promoting the perpetuation of the species, reducing the risk of extinction. According to Rasmussen et al (2015), in any conservation or restoration program for native orchid populations, a definition of factors that limit seed germination and seedling establishment must be investigated

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