Studies on Low Temperature Storage Characteristics of Canary Date Seeds (Phoenix Canariensis)

To investigate the low-temperature tolerance of Phoenix canariensis seeds and isolated seed embryos, along with the physiological changes that occur during cryopreservation, fresh seeds were dried to 25%, 20%, and 15% moisture content and then cryopreserved at -20 ℃ and -196 ℃ (LN₂). The results showed that the survival rate of intact seeds gradually increased with decreasing water content. The survival rate of isolated seed embryo cultures increased with decreasing water content, and the growth rates of seeds and seed embryos dried to 11.6% moisture content were not significantly different from those of the unfrozen groups. The viability of LN₂-preserved intact seeds and isolated seed embryos was higher than that of the -20 ℃ preservation group. After cryopreservation, the sucker part of the seed embryos was damaged more severely than the cotyledon after low-temperature preservation; however, this damage did not affect the subsequent growth of the seed embryos. After drying to an 8% moisture content, the superoxide dismutase (SOD) activity of the seeds was lower than that of fresh seeds, and the CAT activity and MDA content increased. After cryopreservation, the SOD activity and CAT activity of the seeds increased, and the MDA content decreased, whereas the MDA content of the seeds increased significantly after drying, indicating that excessive dehydration was not conducive to seed cryopreservation. Phoeni canariensis seeds are highly resistant to low temperatures and can be preserved in liquid nitrogen for long periods.