Chapter 6 - Germination Ecology of Seeds with Physical Dormancy

Abstract

This chapter discusses germination phenologies of seeds with physical dormancy. It also illustrates the role of drying in the development and maintenance of physical dormancy. Most of the information on the germination requirements of seeds (after physical dormancy is broken) comes from studies in which various laboratory techniques have been used to make seeds permeable. The examples of germination phenology of seeds with physical dormancy are the species growing in a temperate climate with hot, moist summers, and cold, wet winters. Seeds of many species with physical dormancy grow in subtropical or tropical regions with annual wet and dry seasons, and germinate at the beginning of the wet season. Thus, a survey is performed on the methods for artificially breaking physical dormancy, as well as germination requirements for seeds after they become permeable. The role of various environmental factors in the breaking of physical dormancy is also examined. Finally, attention is given to how physiological dormancy is broken in those seeds with both physical and physiological dormancy.