Cryopreservation and Evaluation of Chinese Arbor-Vitae (Biota Orientalis) Seeds

Under cryopreservation conditions or at −196°C, because of extreme reduction of metabolic and physiologic processes, the seed sample or plant organ can survive for a long time. Chinese arbor-vitae (Biota orientalis (L.) Endl.) is one of the endangered forest species in Iran. To preserve B. orientalis seeds under cryogenic conditions, three cryopreservation treatments, including plant vitrification solution 2 (PVS2), 30% glycerol, and seed desiccation, were applied before transferring the seeds into liquid nitrogen. In desiccation, the moisture content of seeds dropped from 8.95% to 5.56% in silica gel at +4°C. All of the treated seeds except control were transferred into liquid nitrogen (−196°C), and preserved for periods of one week, one month, and one year. After removal of the seeds from liquid nitrogen, they were exposed to a heat shock (+42°C), washed, and evaluated by standard germination tests. Furthermore, the second samples of the same seeds were sown in pots and grown in greenhouse (22 ± 4 °C te...