Cryopreservation of Brazilian green dwarf coconut plumules by droplet-vitrification/ Criopreservacao de coqueiro anao verde do Brasil de Jiqui por vitrificacao em gotas

• Published in: Ciência rural Vol. 50; no. 1
• Main Authors: Ledo, Ana da Silva, Santana, Fernanda Vieira, de Oliveira, Annie Carolina Araujo, de Oliviera, Leila Albuquerque Resende, da Silva, Ana Veruska Cruz
• Format: Journal Article
• Language: Spanish
• Published: Universidade Federal de Santa Maria 01.01.2020
• Subjects: Banks (Finance); Time
• ISSN: 0103-8478; 1678-4596
• DOI: 10.1590/0103-8478cr20190020

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.sup.-1] Gelrite [R] culture medium. Plumules were exposed to PVS2 and PVS3 solutions for 15 and 30 minutes and rapidly immersed in liquid nitrogen (-196 [degrees]C). After cryopreservation, they were thawed in culture medium solution (Y3 + 1.2 Msucrose) 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 noncryopreserved 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. Key words: Cocos nucifera L., cryoprotection, PVS2, PVS3. O objetivo desse estudo foi avaliar o efeito das solucoes de vitrificacao e do tempo de exposicao na criopreservacao de plumulas de coqueiro anao verde do Brasil de Jiqui (BGD), pela tecnica de vitrificacao em gotas. Os explantes foram excisados de frutos maduros oriundos do Banco de Germoplasma Ativo de Embrapa Tabuleiros Costeiros, Sergipe, Brasil. Os embrioes foram desinfestados e as plumulas, apos a excisao, pre-cultivadas durante 72 horas em meio de cultura Y3 suplementado com sacarose 0,6 e 2,2 g [L.sup.-1] Gelrite[R]. As plumulas foram expostas em solucoes de PVS2 e PVS3 durante 15 e 30 minutos, e rapidamente imersas em nitrogenio liquido (-196 [degrees]C). Apos a criopreservacao, foram descongeladas na solucao de meio de cultura Y3 com 1,2 M de sacarose, e cultivadas em meio de regeneracao. O delineamento experimental foi inteiramente casualizado em esquema fatorial 2x2 (solucoes de vitrificacao x tempos de exposicao), com cinco repeticoes por tratamento. Os dados foram comparados pelo teste de Tukey a probabilidade de 5%. Observaram-se diferencas significativas na porcentagem de calogenese para a interacao entre solucoes e tempo de exposicao para as culturas nao criopreservadas (-NL), e para o tempo de exposicao apos a criopreservacao (+NL). O PVS2 e o PVS3 combinados com 15 minutos promoveram a maior formacao de calo (70 e 100%, respectivamente) nas culturas de controle. O tempo de exposicao de 30 min, independente da solucao de vitrificacao, promoveu 30% da formacao de calos embriogenicos apos a criopreservacao. Estes resultados contribuem para a conservacao em longo prazo do coqueiro. Palavras-chave: Cocos nucifera L., crioprotecao, PVS2, PVS3.