**1. Introduction**

Seeds germinate to grow and survive from seedlings at a favorable time and place. The prevention of germination in unfavorable circumstances is described as dormancy. Dormancy is where there is a lack of germination in a seed/tuber even though the required conditions (temperature, humidity, oxygen, and light) are provided [1]. Dormancy is a trait gained during evolution to survive in adverse conditions such as heat, cold, drought, and salinity. Dormancy enables plant species to adapt to different geographical regions, showing variations in precipitation and temperature [2]. Dormancy has a significant role in the development of new species and the successful dispersal of existing species [2].

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2017 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

There are two types of seed dormancy in general: seed coat (physical) dormancy and internal dormancy. In seed coat dormancy, the seed coat prevents oxygen and/or water permeating into the seed. Sometimes, dormancy is caused by inhibiting chemicals inside the seed. Seeds with seed coat dormancy can remain on/in the ground without germinating until the seed coat allows water and oxygen to enter the seed or eliminate the inhibiting chemicals. Seed coat dormancy is common in California lilac (*Ceanothus*), manzanita (*Arctostaphylos*), sumac (Rhus), and members of the legume family. Scarification, hot water, dry heat, fire, acid and other chemicals, mulch, and light are the methods used for breaking seed coat dormancy [3].

Physiological conditions causing internal dormancy arise from the presence of germination inhibitors inside the seed. The adverse effects of these inhibitors should be eliminated in order to start germination by using germination-promoting substances such as gibberellic acid (GA3) and potassium nitrate (KNO3 ). The most common inhibitor is abscisic acid (ABA). Sugar maple [4], Norway maple (*Acer platanoides* L.) [5], planetree maple (*Acer pseudoplatanus*) [6], European hazel (*Corylus avellana* L.) [7], white ash (*Fraxinus americana* L.) [8], apple (*Malus pumila* Mill.) [9], northern red (*Quercus rubra* L.), and English oaks [10] are the species that have ABA as an internal inhibitor. Another type of internal dormancy is caused by lack of enzymes, which is required for complete physiological maturation.

Seed coat and internal dormancy can be found together in a species. Seeds with this combined dormancy should be treated by overcoming the problems raised by the impermeable seed coat first, and then overcoming the internal dormancy [3].

In this chapter, the effects of magnetic field strength squirting cucumber (*Ecballium elaterium* (L.) A. Rich.) fruit juice, sodium hypochlorite solutions, and gamma radiation on overcoming dormancy are discussed.
