Effects of temperature and light on germination and early seedling development of the pine pink orchid (Bletia purpurea)

Abstract

Orchid seed physiology is a poorly understood phenomenon owing to an emphasis on production and the challenges associated with propagating orchids from minute seed. We investigated the role of simulated south Florida temperatures and illumination (dark and 12 h photoperiod) in regulating germination and seedling development using asymbiotic seed germination assays of Bletia purpurea. Our objectives were to determine whether in situ germination is limited by seasonal temperatures and to determine whether temperature alters responses to illumination. Bletia purpurea seeds were able to germinate to > 90% under all treatments. The greatest germination after 3 weeks was observed at 29/19°C under continual darkness and at 25°C under dark and illuminated conditions. The slowest germination was observed at simulated winter temperatures (22/11°C). Illumination initially inhibited germination and development, but resulted in equal or greater development by week six. Germination under 22/11°C was strongly inhibited by illumination, indicating an interaction between temperature and light sensing systems.

Orchid Reintroduction Based on Seed Germination-Promoting Mycorrhizal Fungi Derived From Protocorms or Seedlings

“…Orchid conservationists have long been trying to develop ways to reintroduce endangered orchids (Swarts and Dixon, 2009 ; Johnson, 2011 ). The current strategies of orchid reintroduction primarily focus on restoration-friendly cultivation, translocation of individual plants, or transplantation of in vitro cultured seedlings (Zeng et al, 2012 ; Wu et al, 2014 ).…”

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

“…Asymbiotic seed germination has also been used for the multiplication of commercially important orchids, and it has shown to be an effective tool for the orchids mass production for conservation and reintroduction purposes (Stewart and Kane, 2006;Johnson and Kane, 2012;Wu et al, 2014). However, a few researchers have reported the appearance of albino seedling during the germination process, but in different plant species, as Arabidopsis thaliana (Tada et al, 2014) and Delonix regia (Silva et al, 2020).…”

Less is more: low-cost in vitro propagation of an Endangered Italian orchid

“…The importance of temperature in promoting and inhibiting seed germination is well documented and responses are highly variable among species (Johnson & Kane, 2012). Cold stratification (Baskin & Baskin, 2001;Han & Long, 2010) and fluctuating temperatures (Baskin & Baskin, 2001 have also been shown to break dormancy and/or promote germination.…”