ヒシの埋土種子の寿命と発芽能

The existence of persistent seed bank of Trapa sp. was confirmed by the indoor and outdoor observations. The seeds left under room conditions remained alive for more than five years . Among the ungerminated buried viable seeds, some exhibited germination in the outdoor water tank two years after they were collected from the pond bottom. Germination initiated when water temperature became higher than 10℃ and it occurred even under complete darkness. Fluctuation of temperature considerably stimulated germination.