Current status of Ilex (Aquifoliaceae) germplasm cryopreservation

DOLCE, N.R.; REY, H.Y. Y MROGINSKI, L.A.

Yangling

Conferencia; International Conference on Cryopreservation of Horticultural Crops; 2011

College of Horticulture

Seeds of most of the subtropical Ilex species usually contain rudimentary embryos that remain at immature heart or late-heart stage long after the fruits mature and they are also highly sensitive to desiccation and cold. Thus, the seeds of this species are recalcitrant and therefore unsuitable for the dry and/or cold seed storage procedures traditionally employed for plant germplasm preservation. Consequently, the germplasm of Ilex spp. is maintained in the field as ex–situ genebanks. Cryopreservation is an interesting tool for an efficient and economic long-term conservation of plant germplasm. Since 2001, at our Institute we are making efforts to develop protocols in order to establish long-term conservation of genetic resources of some species of Ilex. In this study, we describe procedures for cryopreservation of different explants (fruits, pyrenes or zygotic embryos) of I. paraguariensis, I. dumosa, I. brasiliensis, I. brevicuspis, I. integerrima, I. pseudoboxus, I. theezans, I. microdonta, and I. taubertiana by using vitrification, dehydration and encapsulation-dehydration methods. The explants were immersed in liquid nitrogen and after storage at -196ºC for at least 48 h, they were rewarmed and plants were recovered by in vitro culture on MS/4 (quarter strength salts and vitamins of Murashige and Skoog, with 3% sucrose) supplemented with 0.1 mg/l of zeatin.