Cryopreservation of seeds of Melocactus zehntneri Braun ex Ritter f. and Cereus gounellei Luetzelb ex Schum k. by the vitrification method

Wagner Vendrame,Leonardo Alvarez,Roberto Takane,Ricardo Tadeu,Lamartine Cardoso

doi:10.33158/asb.r106.v6.2020

Abstract

The Brazilian Caatinga houses a number of cacti species, which are considered endangered due to human influence. Two of them, Melocactus zehntneri Braun ex Ritter f. and Cereus gounellei Luetzelb ex Schum k., are endemic of the Brazilian Caatinga. Cryopreservation can provide a means for long-term preservation of endangered plant material. The aim of this study was to evaluate the efficiency of cryoprotectants for the cryopreservation of seeds from these two species. The treatments consisted of immersing seeds in different cryoprotectant solutions and vitrification solutions before storage in liquid nitrogen (NL) at -196 °C, as follows: T1- Control: no cryoprotectants; T2- PVS2 (10 min), T3- PVS2 + phloroglucinol 1% (10 min), T4- PVS2 (10 min) + Supercool 1%; T5- PVS2 + phloroglucinol 1% (10 min) + Supercool 1%. Seed germination was evaluated after cryopreservation. The experimental design was completely randomized with five treatments and five replicates per treatment. Seed moisture at the beginning of the experiment was 6.2% for M. zehntneri and 7.8% for C. gounellei. There were no statistically significant differences for the seed germination percentage among the different treatments. Therefore, we concluded that seed of these two cacti species can be cryopreserved directly without the need for cryoprotectant solutions.

Highlights

In Brazil, the Caatinga has a rich diversity of cacti species
Cryopreservation is a technique that allows the long-term storage and conservation of plant material, including seeds, pollen, and tissues, and can assist with the maintenance, preservation and the development of studies of the plant species that occur in endangered habitats
The germination tests for both cacti species were 83% for M. zehntneri and 94% for C. gounellei

Summary

Introduction

In Brazil, the Caatinga has a rich diversity of cacti species. The most endemic cacti catalogued include species in the genera Cereus, Pilosocereus and Melocactus (Taylor & Zappi, 2004; Queiroz, 2006). Cryopreservation is a technique that allows the long-term storage and conservation of plant material, including seeds, pollen, and tissues, and can assist with the maintenance, preservation and the development of studies of the plant species that occur in endangered habitats. Cryopreservation allows the preservation of biological material in liquid nitrogen at extremely low temperatures, in the liquid (-196 oC) or vapor phase (-150 oC), while maintaining the original characteristics of the material and allowing recovery after thawing (Sakai & Engelmann, 2007; Vendrame & Faria, 2011). Cryopreservation allows the long-term preservation of different plant materials, in contrast to short-term storage when using other techniques (Bajaj, 1995; Galdiano, Lemos, Faria, & Vendrame, 2012; Lopes, Almeida, Carvalho, & Bruno, 2013). The use of cryoprotectant solutions is essential for the successful recovery of organs and tissues and regeneration of plants after cryopreservation

Objectives

Methods

Results

Conclusion