Conservation, cryopreservation and behavior of reserve material throughout storage of bamboo seeds [Dendrocalamus asper (Schult. & Schult.f.) Backer ex K.Heyne]

Dendrocalamus asper is a woody bamboo species that has monocarpic flowering with long flowering cycles and irregular seed production, which lose viability quickly when stored under inadequate conditions. In this context, we have characterized the behavior of D. asper seeds stored under varying temperatures in the medium to long term and evaluated the behavior of reserve material throughout storage. Moreover, a simplified protocol for the cryopreservation of seeds was developed. Seeds with 11% moisture content were stored at 25 (control), 6, − 20 and – 196 °C for 0, 30, 90, 180, 360, and 600 days. After each storage period, the seeds were inoculated in vitro for germination and then the obtained plants were acclimatized. During the storage periods of 0, 360, and 600 days, seed samples were collected for biochemical analyses. In a second step, seeds were desiccated, and a portion of the seeds was placed to germinate in vitro, while a second portion was immersed in liquid nitrogen (− 196 °C) for 48 h. After this period, the cryopreserved seeds were thawed and inoculated in culture medium for germination. D. asper seeds were found to maintain viability for up to 600 days when stored at − 20 °C and – 196 °C, producing normal, whole plants. At 6 °C, the seeds can only be kept for up to 360 days. At 25 °C, there is a decrease in viability at 360 days and a marked reduction in germination at 600 days, in addition to abnormal plant development. The analysis of the biochemical composition of the seeds revealed starch as the main reserve material, followed by proteins and, in smaller amounts, lipids. Desiccation of seeds for up to 144 h resulted in a moisture content of about 5%. At this humidity, the seeds showed no differences in germinability for either the control treatment or cryopreserved seeds. The results of this study indicate, in a pioneering way, orthodox behavior of D. asper seeds, which tolerated desiccation up to 5% humidity, besides supporting storage at – 20 °C and in liquid nitrogen, with maintenance of viability for up to 600 days.