Detailed Explanation of Key Technical Points for Schisandra Harvesting and Seed Treatment

Schisandra seeds have a dormant characteristic: the seed coat is hard and smooth, with an oil layer beneath the coat that resists water and air penetration; in naturally matured seeds, the embryo is small and has after-ripening characteristics. Seeds with the flesh removed have a relatively short lifespan; generally after 2 months of dry storage at room temperature, seed viability declines. Wild seeds usually have an extremely high rate of empty grains. Mature seeds commonly come in two colors: one is darker, appearing dark red, with higher maturity but slower germination; the other is orange-red and germinates more easily.

Northern schisandra generally enters the coloring stage in late July. The sugar pigments in the fruit increase as the fruit matures, then show a declining trend in the later stage. The fruit skin is thin and not resistant to compression, and the berries drop easily, so late August to mid-September is the optimal harvest period, when the various components in the fruit tend to stabilize.

After harvesting, the seeds should be promptly separated from the flesh using a seed-pressing machine; the pressed juice is an excellent raw material for schisandra beverages and schisandra wine. After mechanical separation, the seeds are washed clean with water, the empty grains are floated off, and they are dried in a cool place. It is best to drain the water for 1-2 days, then treat them by mixing with disinfected river sand at a 1:3 ratio. Dried seeds are generally soaked in mid-to-late December, then mixed with sand, with the temperature controlled between 0°-5°C.

Northern seeds can be overwintered in various ways, including cellar storage, box storage and frozen storage. The low-temperature stratification treatment time for seeds is about 80-90 days.

In the early stage of schisandra seed breeding, attention should be paid to the safe storage of seeds, preventing high temperatures and excessive moisture, and ensuring ventilation in the storage area. In the middle stage, seeds should be promptly subjected to low-temperature or stratification treatment. Northern schisandra seeds are of the deep dormancy type and easily lose their germination capacity. The main reason for their dormancy is that the embryo is not fully differentiated and its morphological development is immature; it needs to complete development under storage conditions at 8°C-15°C, and embryo differentiation generally requires about 30 days. In the later stage, the low-temperature storage time generally needs about 60 days, and the whole process requires 80-90 days. After storage, before germination acceleration, the seeds should be promptly subjected to alternating temperature treatment between -10°C and 15°C, with continuous alternating temperature treatment 3-4 times; the alternating temperature period between 10°C and 12°C should be longer, generally about 15 days. In this way, when the seeds are germinated at 20°C-25°C, the germination rate is relatively high. Generally after about 10 days of germination acceleration, most seeds crack open and expose the radicle, and can then be sown.