• DOI:10.1086/330863
• Corpus ID: 84608408

The Effect of External Conditions upon the After-Ripening of the Seeds of Crataegus mollis

@article{DavisTheEO,
  title={The Effect of External Conditions upon the After-Ripening of the Seeds of Crataegus mollis},
  author={Wilmer E. Davis and R. Catlin Rose},
  journal={Botanical Gazette},
  volume={54},
  pages={49 - 62}
}

• W. Davis, R. C. Rose
• Published 1 July 1912
• Biology
• Botanical Gazette

It is well known that the seeds of many plants do not germinate immediately after ripening, but only after a period of rest which in some cases no doubt extends into years. NOBBE and HANLEIN (i6), for example, kept certain weed seeds under germinating conditions for a period of II73 days without germination. While various workers have done much in the way of adding to the list of seeds that require a rest period before germination, little has been done to determine the real cause of this delay or dormancy on the part of the seed. During this period, it is assumed that the seed undergoes certain changes, at the completion of which germination may take place. This period of preparation for germination has been termed the after-ripening period. The term after-ripening then may be made to include the necessary protoplasmic changes antecedent to germination; changes involving the release of digestive and respiratory enzymes, thus leading to rapid metabolism; or disintegration or other modifications of incasing structures that limit the water or oxygen supply or even mechanically hinder growth. But in relatively few cases do we know to which of these dormancy is due. In most literature the cause is assumed to be the need of protoplasmic changes in the embryo. In this paper we have used the term after-ripening in reference to embryonic changes whether protoplasmic or metabolic, in contrast to those changes that merely affect the incasing structures. By germination we mean the growth of the hypocotyl. Many more or less successful attempts have been made to shorten or eliminate altogether this period of inactivity on the part of the embryo by certain stimuli designed to arouse the dormant protoplasm to activity. Lately FISCHER (5) observed that seeds of certain water plants might be kept in water free from fermentation