In Vitro Propagation and Germplasm Conservation of Wild Orchids from South America

Abstract

Orchids are an important part of plant biodiversity on the planet due to their high variability among species and their habitats. South America presents more than thirty percent of all known orchid species, being Colombia, Ecuador, Brazil, Peru, and Bolivia between the richest countries in the world in terms of orchid biodiversity. Nevertheless, concerning to the orchid conservation status, in Colombia precisely orchids occupy the unlucky first place as the plant family with the highest number of threatened species. Similar situation is happening in the rest of the South American countries. The two main threats to orchid survival are both anthropogenic: the first one is deforestation, and the second largest threat to orchids is collection from the wild. One desirable action to safeguard these endangered species is to develop procedures that make possible their massive propagation, which should provide material for the eco-rehabilitation of specimens into their natural habitats, the exchange with other entities, the supply to orchid merchants for avoid extractions of nature, and the availability of material for future research. Likewise, the development of systems that allow the ex situ conservation of orchid germplasm is imperative. This chapter reviews the progresses of different in vitro approaches for orchid propagation and germplasm conservation, safeguarding the genetic biodiversity of these species. Several study cases are presented and described to exemplify the protocols developed in the Botanical Institute of Northeast (UNNE-CONICET) for propagating and long-term storing the germplasm of wild orchids from Argentina (Cattleya lundii, Cohniella cepula, Cohniella jonesiana, Gomesa bifolia, Aa achalensis, Cyrtopodium brandonianum, Cyrtopodium hatschbachii, Habenaria bractescens). Moreover, it has been attempted to put together most of the available literature on in vitro propagation and germplasm conservation for South American orchids using different explants and procedures. There are researches of good scientific quality that even cover critical insights into the physiology and factors affecting growth and development as well as storage of several orchid materials. Anyway, studies are still necessary to cover a mayor number of South American species as well as the use of selected material (clonal) for both propagation and conservation approaches.

Morpho-anatomy of in vitro germination and cryopreservation of the orchid Cattleya crispa (Orchidaceae)

“…This event occurred seven days after sowing. However, in some species of orchids the onset of germination occurs two months after seed sowing (Dolce et al, 2020). Subsequently, the C. crispa seeds form the protocorms, which are observed in different stages of development throughout the evaluated time.…”

In vitro growth of Cattleya nobilior Rchb. f.: culture media, sealing systems and irradiance

“…Some adjustments are still necessary in the culture medium formulation for each orchid species, especially native ones. Some authors report that banana acts as a vitamin supplement and potassium source, and stimulates growth and rooting in in vitro propagation (George et al 2008, Ferreira et al 2010, Su et al 2012, Dolce et al 2020). However, this supplement is still little studied in the in vitro culture of orchid species from the Brazilian Savanna.…”

“…In the present study, the supplementation with banana pulp improved the root system quality. This fruit can stimulate rooting, due to its amount of potassium and mineral salts, its pulp being also a rich source of cytokinins, auxins and gibberellins (Khalifah 1966, Lahav & Gottreich 1984, Arditti and Ernst 1993, Dolce et al 2020.…”