Effect of water content and biochemical cell state on the germination rate of cryopreserved Butia eriospatha embryos (Arecaceae)

Authors: GOETEN, DANIELA - Universidade Federal De Santa Catarina (UFSC); ELIAS, ROSA - Universidade Federal De Santa Catarina (UFSC); GIACOMOLLI POLESI, LUIZA - Universidade Federal De Santa Catarina (UFSC); Walters, Christina; GUERRA, MIGUEL - Universidade Federal De Santa Catarina (UFSC); STEINER, NEUSA - Universidade Federal De Santa Catarina (UFSC)

Submitted to: Plant Cell Tissue and Organ Culture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/28/2022
Publication Date: 11/30/2022
Citation: Goeten, D., Elias, R.A., Giacomolli Polesi, L., Walters, C.T., Guerra, M.P., Steiner, N. 2022. Effect of water content and biochemical cell state on the germination rate of cryopreserved Butia eriospatha embryos (Arecaceae). Plant Cell Tissue and Organ Culture. 152:339–356. https://doi.org/10.1007/s11240-022-02411-4.
DOI: https://doi.org/10.1007/s11240-022-02411-4

Interpretive Summary: Palms (Arecaceae) are distributed worldwide and are of extreme economic importance globally. These plants are propagated by seed and generally germinate slowly and in low proportions. Seeds from palms vary greatly in their tolerance of desiccation, making it difficult to preserve them ex situ as genetic resources. This study explores germination and desiccation tolerance of Butia eriospatha embryos, one of several species of Butia growing in the Brazilian rain forest. The first challenge of the study was to develop a reliable in vitro germination assay so that response to stress challenges could be measured. We found that B. eriospatha exhibited significant tolerance of drying and expressed post-drying metabolites that indicate stress and possible enzymatic recovery from oxidative damage. Because these embryos survive substantial water stress, it is possible to optimize water contents and cooling rates to avoid water freezing that is lethal to most recalcitrant (desiccation sensitive) seeds. For this reason, we are optimistic that the genetic resources of this important genus can be preserved in ex situ genebanks.

Technical Abstract: The Brazilian rain forest is home of about 50% of the world’s plant biodiversity, and many species have a high economical potential. Butia eriospatha is an endemic species of the Brazilian Atlantic Forest and it is in a vulnerable conservation status. due to human pressures. In this species, plants are only propagated sexually by seeds which show dormancy and germinate slowly with overall low seedling emergence. To manage the limited seedling establishment and conservation strategies of this species, the viability, antioxidant activity, and profiles of polyamines and amino acids of desiccated B. eriospatha embryos were assessed. Mature and desiccated embryos were germinated under in vitro conditions on Murashige and Skoog culture medium, which was supplemented with hormones and antioxidants. With this method, germination rates of 93% could be achieved. Embryos did not survive drying to water contents lower than 0.14 g H2O g DW-1, a water content considered to be its desiccation tolerance threshold. A significant increase in putrecine (PUT) was observed during desiccation. Increase in guaiacol peroxidase (GPX) and ascorbate peroxidase (APX) activity lead us to suggest that they are the main enzymes involved in cellular protection during desiccation. An increase of amino acids content, especially glutamic acid (Glu), leucine (Leu), lysine (Lys), glutamine (Gln), which are known as osmoprotectors also was observed. Embryos previously desiccated to 0.14 g H2O g DW-1 were successfully cryopreserved, and showed a post-thawing recovery rate of 85%. The physiological and biochemistry approach of this study associated to a cryopreservation protocol can be used for plant genetic resources conservation of other Arecaceae species in the world.