Abstract: The weight of a thousand seeds of Dipteronia dyeriana Henry from ex situ plants 2346 . 5 g is lighter than that of seeds from the wild plants 3255 . 6 g . TTC colouring seed vitality tests indicated that : 1 . in 25℃ water environment, 60 d seeds had no vitality; 2 . seeds 52% stored up in the wild for 180 d had vitality; 3 . seeds 58% stored up 510 d in pot had vitality; 24% seeds in room also had vitality; in 4℃ 96% seeds had vitality; in 15℃ 36% seeds had vitality; in 25℃ seeds had no vitality . In 6℃ , the germination rate of seed without testa was 98% in 5 months , while in constant temperature of 15℃、25℃、30℃ and in condition of changing temperature had no seed germination . Low temperature ( 6℃ ) was the most suitable temperature for the germination of D. dyeriana . No light needed for seed germination . Sowing in the wild , there were 17. 2% seeds germinated after a winter and 58% seeds germinated after two winters and one summer in pot . Its own seed character of D. dyeriana was one of the main factors causing the extinction of the species .

Key words: Rare plants