Abstract

The native cacti species from Bahia, Discocactus zehntneri, Pilosocereus gounelleiand Stephanocereus luetzelburgii, as other members of the Family Cactaceae, have been dramatically affected by illegal traffic, and with the destruction and fragmentation of their habitats. Considering the potential extinction risks for endangered species, and the several applications of these species, some actions on ex situconservation of cacti are required. Thus, this work aimed to evaluate the physiological quality of seeds from D. zehntneri, P. gounellei and S. luetzelburgii stored in liquid nitrogen (-196°C) for 0, 7 and 30 days. For this purpose, seeds of the three species were transferred to cryovials and then immersed directly in liquid nitrogen for 7 or 30 days. After the storage period, the seeds were removed from the nitrogen tank, and thawed for 1 h at ambient temperature and subsequently chemically sterilized. The seeds were inoculated onto Petri dishes lined with two layers of germitest paper. The germination rate of the three species was not reduced by exposure to liquid nitrogen, as well as D. zehntneri that had the best results for speed and germination rate observed in seeds stored for 30 days.

Key words: Cacti, cryoconservation, ex situ conservation, germination.