Hardseedness of Ammopiptanthus nanus and Ammopiptanthus mongolicus

Hardseedness of Ammopiptanthus mongolicus and Ammopiptanthus nanus was examined through imbibition, germination, and ageing testing in this study. The effects of soaking duration, soaking temperature, hardseedness level, and seed coat color on seed imbibition were investigated. Germinability and viability of hard seeds and soft seeds (used as controls) were also analyzed through ageing testing. Imbibition percentage increased with lengthening of soaking duration, rising of soaking temperature, decreasing of seed moisture content, and darkening of seed coat color. Harder seeds had higher germination percentage and germination index compared to softer seeds. They tolerated ageing and their storability was higher. The seeds of both plants tended to become hard at maturity with long storability, which could be considered as an adaptation to the dry and extremely cold environments in the desert of Northwest China. However, hard seeds could not imbibe and germinate.