Cryopreservation of seeds of Acacia tortilis and Acacia nilotica

Cryopreservation or storage at -196°C is a new and most important method of preserving plant species materials for a long period of time. Using cryopreservation، most of seeds، vegetative organs، cells، and pollens can be preserved for a long time. Cryogenic conditions stop much of the metabolic processes of the cells and، period of preservation dramatically increases. Seeds of Acacia nilotica and Acacia tortilis were collected from Hormozgan provience، located in south part of Iran. Three pretreatments including vitrification (PVS2)، desiccation and 30% glycerol were applied before transferring the seeds into liquid nitrogen. Seeds were stored in liquid nitrogen for one month. Following removal from liquid nitrogen، the seeds were subjected to heat shock (+42 °C) and germinated under laboratory conditions. Different attributes including seed germination percentage، root and shoot length، germination speed، root/shoot length ratio and seed vigor index (VI) were recorded and statistically analyzed. Second sample of the same seeds were sown in pots and grown under greenhouse conditions. High seed germination percentage (<80%، <75% and <41% for Acacia nilotica and Acacia tortilis respectively) and other attributes، either in laboratory or greenhouse conditions revealed the cryotolerance of seeds of the species. In greenhouse experiments، plants developed from cryogenic seeds grew normally and did not show any abnormality compared to those of the control plants. In general، results of the present study indicated that cryopreservation (-196 °C) technology can be used for long-term preservation of Acacia nilotica and Acacia tortilis seeds.