Cryopreservation of Brazilian green dwarf coconut plumules by droplet-vitrification

Ana Da Silva Lédo,Ana Veruska Cruz Da Silva,Annie Carolina Araújo De Oliveira,Fernanda Vieira Santana,Leila Albuquerque Resende De Oliveira

doi:10.1590/0103-8478cr20190020

Ana Da Silva Lédo, Ana Veruska Cruz Da Silva + Show 3 more

Open Access

https://doi.org/10.1590/0103-8478cr20190020

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Abstract

ABSTRACT: This study evaluated the effect of vitrification solutions and exposure time on the cryopreservation of Brazilian green dwarf coconut plumules (BGD) using the droplet vitrification technique. Explants were excised from BGD mature fruits from the Active Germplasm Bank of Embrapa Tabuleiros Costeiros, Sergipe, Brazil. Firstly, embryos were disinfected, and after excision, plumules were pre-cultivated for 72 hours in Y3 + 0.6 M sucrose + 2.2 g L-1 Gelrite® culture medium. Plumules were exposed to PVS2 and PVS3 solutions for 15 and 30 minutes and rapidly immersed in liquid nitrogen (-196 ºC). After cryopreservation, they were thawed in culture medium solution (Y3 + 1.2 M sucrose) and cultured in regeneration medium. The experimental design was completely randomized in a 2x2 factorial scheme (vitrification solutions per exposure times), with five replicates per treatment. Data were compared by the Tukey’s test at 5% probability. Significant differences were observed in the callogenesis percentage for the solutions x exposure time interaction for non-cryopreserved cultures (-NL) and for exposure time after cryopreservation (+NL). PVS2 and PVS3 combined with 15 minutes of exposure promoted the highest callus formation (70 and 100%, respectively) in control cultures. The exposure time of 30 min, regardless of vitrification solution, resulted in 30% embryogenic callus formation after cryopreservation. These results contributed to the long-term conservation of coconut palm.

Highlights

Coconut (Cocos nucifera L.) is known as the “tree of life”, because each component of the palm tree can be used for fresh consumption or transformed by industrialization
There is scarce literature about the cryopreservation of plumules and zygotic embryos from accessions collected in Brazil such as Brazilian green dwarf (BGD accession) and Brazilian tall genotypes
This study evaluated the effect of vitrification solutions and exposure time on the cryopreservation of Brazilian green dwarf coconut plumules (BGD) accession plumules using the droplet vitrification technique

Summary

INTRODUCTION

Coconut (Cocos nucifera L.) is known as the “tree of life”, because each component of the palm tree can be used for fresh consumption or transformed by industrialization. There is scarce literature about the cryopreservation of plumules and zygotic embryos from accessions collected in Brazil such as Brazilian green dwarf (BGD accession) and Brazilian tall genotypes. Recent studies have shown the feasibility of the vitrification technique for the cryopreservation of BGD zygotic embryos (LEDO et al, 2018). Regeneration techniques by somatic embryogenesis from plumules are more interesting from the point of view of breeding and conservation of genetic resources because they allow obtaining higher number of plants (NGUYEN et al, 2015). Studies with cryopreserved of Malayan yellow dwarf coconut plumules by encapsulationdehydration reached only 20% survival (N’NAN et al, 2008). This study evaluated the effect of vitrification solutions and exposure time on the cryopreservation of BGD accession plumules using the droplet vitrification technique

MATERIALS AND METHODS

RESULTS AND DISCUSSION

CONCLUSION