Cryopreservation Approach for the Germplasm Conservation of the Tropical Forest Tree Species

Abstract

Cryopreservation approach for the germplasm conservation of three useful tropical forest tree species (Cedrela odorata L., Guazuma crinita Mart., and Jacaranda mimosaefolia D. Don.) were carried out using shoot-tip or roottip explants from in vitro-grown plantlets by four cryopreservation methods ((1) simple freezing, (2) rapid freezing, (3) slow pre-freezing, and (4) dehydration method). The effects of cold hardening treatments (5, 10, 15, and 20/10°C) and pre-culture (dehydration treatments) were also studied.The best results were achieved when the shoot-tips were cooled by slow pre-freezing before immersion in liquid nitrogen (LN). Survival and plant recovery rates of 50 and 20%; and, 50 and 15%; were obtained in cryopreserved shoot-tips of C. odorata and G. crinita, respectively. Although the effects of cold hardening and/or pre-culture treatments are not clear, apparently they were not effective in enhancing the survival or plant recovery rate after immersion in LN because these species may be intolerant of low temperature treatments of long duration and/or to drastic dehydration treatments.The cryopreservation of shoot-tips from tissue-cultured plants can be considered as a feasible alternative for the long-term storage of C. odorata, G. crinita, and J. mimosaefolia germplasm.