The Causes of Dormancy and the Changes of Endogenous Hormone Content in <i> Cephalotaxus sinensis </i>Seeds

Abstract

In many wild species, seeds are dormancy at maturity and will not germinate even under favorable environment conditions. Dormancy is a complex trail that is determined by many factors. Some studies have shown that cold stratification and the application of gibberellic acid (GA) can break seed dormancy and promote seed germination. The present study investigated the causes of plant dormancy and the effect of cold stratification and different concentrations of exogenous GA 3 in regulating Cephalotaxus sinensis seed germination. Results showed that C. Sinensis seeds have good water permeability, which suggested that seed coats were not the main cause that inhibited the seed germination. There were germination inhibitions in all parts of seeds, and the order of inhibitory effect was: testa < endosperm (embryo), which indicated that existence of germination inhibitions was the main reason causing seed dormancy. Endogenous GAs and IAA (indole-3-acetic acid) content increased, while ABA (abscisic acid) content decreased over the experiments. ZR (zeatin riboside) content decreased in the early phase of cold stratification, but rebounded by the end of the experimental period. The changes of endogenous hormone indicated that GA, IAA and ZR played a positive role in seed germination, whereas ABA was associated with seed dormancy. Besides, the relative ratio of GA/ABA, IAA/ABA and ZR/ABA may play a more important role than their absolute level during the seed development.

Study on Dormancy Mechanism and Breaking Dormancy Method of &lt;i&gt;Viburnum sargentii&lt;/i&gt; Seeds

“…The slower growth has a major relationship. This is the same as the previous studies on Styraxobassia [13] and Ferula fukanensis [14].…”

Effect of gibberellic acid and potassium nitrate seed treatments on the emergence and seedling vigor of Amaranth and Cleome gynandra

“…Physiological dormancy in seeds hinders radicle protrusion, thus the seeds are unable to emerge until chemicals ABA and gibberellic acid (GA 3 ) changes take place (Hu et al., 2018; Nur et al., 2104; Ochuidho & Modi, 2013; Soltani et al., 2017). Chemical changes are caused by the reduced hormone balance between growth inhibitors, such as ABA and growth regulators (GA 3 ) (Piskurewicz et al., 2008; Yan et al., 2016). Dormant seeds have high levels of ABA and low levels of GA 3.…”

“…Dormant seeds have high levels of ABA and low levels of GA 3. Thus, seeds emerge with a low concentration of ABA and a high concentration of GA 3 can emerge (Yan et al., 2016). A low concentration of ABA leads to reduced DOG 1 gene that hinders germination, therefore if it is low, germination can be promoted.…”