Microbial Inoculation is Crucial for the Endocarp Opening of Panax ginseng Seeds in Indoor Warm Stratification

Panax ginseng C.A. Meyer is one of Korea's most popular traditional medicinal plants. Since ginseng seeds have morpho-physiological dormancy and a very short lifespan, the harvested seeds need outdoor warm and cold stratification for 100 days each. The seeds are covered by a fruit coat (endocarp), which should be opened during the warm stratification. Hence, farmers need to dehisce (open the endocarp) the seeds annually. The author examines conditions for embryo growth, dehiscence percentage, and endo-carp hardness as a factor of temperature, watering, stratification substances, solution scarification, microbial inoculation on the seed endocarp, etc. Watering, temperature (17.5°C), and aeration are crucial for embryo growth as a germination condition. Moreover, microbial-mediated decomposition of the endocarp is necessary for dehiscence and further embryo development. This study suggests that a combination of embryo growth and microbial-mediated decomposing of the endocarp during warm stratification is a prerequisite for the dehiscence of ginseng seeds, implying physical dormancy and morpho-physiological dormancy. The un-dehisced seeds of three P. ginseng varieties and one P. quinquefolius (American ginseng) were dehisced indoors with microbial inoculation instead of sand as a stratification substrate. This approach opens the door for year-round indoor dehiscence of ginseng seeds without sand.