Morphogenesis Changes in Protocorm Development during Symbiotic Seed Germination of Dendrobium chrysotoxum (Orchidaceae) with Its Mycobiont, Tulasnella sp.

The endangered epiphytic orchid, Dendrobium chrysotoxum, is known for its ornamental and medicinal uses. However, knowledge of this orchid’s symbiotic seed germination, protocorm anatomy, developmental morphology completely unknown. In study, we investigated the process development D. chrysotoxum during germination using anatomical technologies scanning electron microscopy. There are six stages that were morphologically anatomically defined germination. embryo transformed into a at stage two, protrusion developed from top three elongated to form cotyledon four. stem apical meristem (SAM) was initiated well first leaf root appeared five six, respectively. hyphae entered through micropylar end one then invaded rhizoids when formed. Invading fungal colonized inner cortex base protocorms, formed pelotons, digested by host cells later. We conclude programmed embryo, which determines structure function protocorm. two zones in polarized include smaller zone, forms shoot end, larger mycorrhiza house symbiont basal end. These results will provide important insights further research on mechanisms underlying orchid-fungi symbiosis enhance understanding orchid evolution.