Abstract The conservation of plant genetic resources is fundamental for the development of agriculture. The development of efficient cryopreservation protocols has become an effective tool to preserve cells, tissues and organs of different plant species. We sought here to develop an efficient method of cryopreservation of Eucalyptus grandis employing the V cryo-plate technique. This experiment examined the exposure of shoot tips to three different cryoprotectants (PVS2, PVS3, and PVS4). The cryoprotectants PVS2 and PVS4 proved to be more efficient among the cryoprotectants tested, as 44.4% of the shoot tips immersed in those solutions survived, and 31.1% generated new shoots. Ethylene glycol was found to be a key compound for the successful cryopreservation of shoot tips, in light of its low toxicity as compared to other cryoprotective compounds. Thus, the methodology developed here represents an effective method for the conservation of E. grandis germplasm through cryopreservation and the use of the V cryo-plate technique.

RESUMO Mudas de Peltophorum dubium (Sprengel) Taubert foram submetidas a 60 dias de alagamento, com e sem a aplicação de cálcio. Durante esse período, foram avaliados: crescimento, anatomia radicular e teor de clorofila. As taxas de crescimento relativo (TCR) de raiz e parte aérea foram maiores nas plantas não alagadas. O alagamento, com e sem aplicação do cálcio, afetou negativamente o comprimento das raízes, mas isso não afetou a parte aérea e o diâmetro do caule. As análises anatômicas mostraram aumento na espessura do esclerênquima nos tratamentos alagado e alagado + Ca+ aos 15 e 60 dias, e o diâmetro dos vasos foi menor aos 45 dias. Nos teores de clorofila foram registradas diferenças entre os tratamentos, porém não foram diferenças estatisticamente significativas. Os resultados indicam que a Peltophorum dubium é espécie candidata para reflorestamento em áreas sujeitas a alagamento contínuo por até 60 dias, uma vez que não foi observada mortalidade.

ABSTRACT Peltophorum dubium (Sprengel) Taubert seedlings were submitted to 60 days of flooding, with and without Ca+. During this period, growth, root anatomy and chlorophyll content were analyzed. The relative growth rates (RGR) of roots and shoots were higher in non-flooded plants. The flooded treatments, with and without Ca+, have affected the roots growth but did not affect the shoot and the stem diameter. The anatomy analysis showed thickening of the sclerenchyma in 15 and 60 days in the flooded treatments with and without Ca+, and the vessel diameter was smaller at 45 days. The chlorophyll content differed, however it was not statistically significant. The results indicate that Peltophorum dubium as candidate specie for reforestation in areas subjected to continuous flooding for up to 60 days, since no mortality was observed.