Orchid cryopreservation

Abstract

Orchids are lush and highly valuable plants due to their diversity and the beauty of their flowers, which increases their commercialization. The family Orchidaceae comprises approximately 35,000 species, distributed among more than 1,000 distinct genera and 100,000 hybrids, totaling approximately 8% to 10% of all flowering plants. With the advance of agriculture and the constant destruction of their natural habitat, orchid species are collected in an indiscriminate manner by collectors and vendors, and this extractive activity threatens many species with extinction, drastically reducing their genetic variability in nature. Therefore, it is essential to seek alternatives that make the preservation of such species feasible using techniques with low maintenance costs that provide greater storage time and that enable good phytosanitary conditions for the plant material for commercial use. Cryopreservation involves the conservation of biological materials at ultra-low temperatures, generally in liquid nitrogen at -196 ºC or in its vapor phase at -150 ºC. This is the only technique currently available for the long-term preservation of the germplasm of plant species that are vegetatively propagated or that have unviable, recalcitrant or intermediate seeds. The objective of this bibliographic review is to report on the importance, methods and application of cryopreservation for orchids. According to the studies reviewed, this is an incipient, developing and relevant field that generates a lot of discussion and requires further research relative to the type of treatment to use for cryopreservation and the methodology to be applied according to the species. The types of methods that are used for cryopreservation and the large variation in the responses of orchids to the cryopreservation methods observed in this study emphasize the need for the development of more appropriate protocols for the preservation of orchids.Index terms: Preservation, Orchidaceae, ex situ conservation, freezing tolerance, extinction. RESUMOAs orquídeas são plantas exuberantes e apresentam alto valor agregado devido à diversidade e à beleza de suas flores, o que incrementa a sua comercialização. A família Orchidaceae compreende cerca de 35.000 espécies, distribuídas em mais de 1000 gêneros distintos e 100.000 híbridos, totalizando cerca de 8% a 10% de todas as plantas com flores. Com o avanço da agricultura e a constante degradação do seu habitat natural, as espécies de orquídeas são coletadas de maneira indiscriminada por colecionadores e comerciantes. Este extrativismo ameaça muitas espécies de extinção reduzindo drasticamente a sua variabilidade genética na natureza. Portanto, torna-se fundamental a busca de alternativas que viabilizem a preservação destas espécies, com a utilização de técnicas que apresentem baixo custo de manutenção, que proporcionem maior tempo de armazenamento, e que possibilite ao material vegetal boas condições fitossanitárias para utilização comercial. A criopreservação compreende a conservação de material biológi...

Cryopreservation of papaya seeds cv. Sukma, Callina, and Caliso: Effect of loading treatment and immersion time in plant vitrification solution-2

“…The seeds cell wall after cryopreservation were more stretch and some were damaged. Vendrame et al (2014) stated the similar report that cryoprotectant exchange the intracellular water of orchid seeds (orthodox seeds), so the membrane content is more solid and make amorphous or vitreous forming when storage in the liquid nitrogen. There was some membrane content that did not make amorphous form so the ice crystal forming and cell damage.…”

“…Immersion more than 15 min (overexposure) to PSV2 may cause damage to the cells owing to the toxic nature of the PVS2 or excessive dehydration (Kaczmarczyk et al 2012). Vendrame et al (2014) stated that cryoprotectant (PVS2) was toxic that caused osmotic stress, cell death, and cell morphogenetic. Some of papaya seeds cv.…”

“…Caliso needs loading treatment in order to the cells could adapt well while stored in the liquid nitrogen. Loading solution could increase the dehydration tolerance on sensitive cryoprotectant plants (intolerance to dehydration and osmosis stress) (Vendrame et al 2014). Loading treatment increased the membrane cell permeability in order to cryoprotectant could enter the membrane cell (Vendrame et al 2014).…”

“…The main process in vitrification was done by cryoprotectant. Cryoprotectant is solution that protects cell from freezing and thawing (Vendrame et al 2014). Plant Vitrification Solution 2 (PVS2) is cryoprotectant that has composition 30% glycerol, 15% ethylene glycol, and 15% DMSO on MS media with 0.4 M sucrose (Sakai et al 1991).…”

Estudos Interdisciplinares em Ciências Biológicas, Saúde, Engenharias e Gestão

“…Possuem cerca de 850 gêneros e 20.000 espécies no mundo, sendo que no Brasil, podem ser encontrados cerca de 236 gêneros e 2.430 espécies (APG III, 2009). Embora a diversidade de orquídeas seja alta no Brasil e em diversas partes do mundo, muitas espécies são vítimas de extrativismo, levando muita das vezes à sua extinção (VENDRAME et al, 2014).…”