A Travel through Landscapes of Seed Dormancy

Abstract

Basic features of seed dormancy are illustrated. The seed overall regulatory network governs seed metabolism and development, and it is coordinated by plant hormones. A functional model focused on abscisic acid (ABA), the foremost plant hormone in dormancy, is used as a framework to critically discuss the literature. Gibberellins (GAs) have a main role in germination, and the ABA–GAs balance is a typical feature of the seed state: ABA dominates during dormancy and GAs prevail through germination. Thus, the literature converges toward envisaging the development switch between dormancy and germination as represented by the ABA/GAs ratio. The ABA–GAs antagonism is based on mutual inhibition, a feature of the regulatory network architecture that characterizes development trajectories based on a regulatory circuit with a bistable switch. Properties of such kind of regulatory architecture are introduced step by step, and it is shown that seed development—toward either dormancy or germination—is more properly represented by a tristable regulatory circuit, whose intermediate metastable states ultimately take one or the other development trajectory. Although the ABA/GAs ratio can conveniently represent the state of the seed overall regulatory network along the seed development trajectory, specific (unknown) dormancy factors are required to determine the development trajectory. The development landscape is shown to provide a well-suited representation of seed states travelling along developmental trajectories, particularly when the states are envisioned as regulatory circuits. Looking at seed dormancy in terms of regulatory circuits and development landscapes offers a valuable perspective to improve our understanding of this biological phenomenon.

Study on Dormant and Germination Characteristics of Chinese Olive (Canarium album) Seeds

“…For seeds with physiological dormancy, the balance between their endogenous ABA and GA 3 contents can be regulated to break seed dormancy [45]. Gibberellin is effective in lifting the physiological dormancy of seeds and promoting seed germination [46]. In this study, it was found that low-temperature treatment combined with gibberellin (300 mg/L) could promote seed germination more effectively.…”

“…The germination of Chinese olive seeds after a short period of cold stratification or gibberellin treatment suggests that olive seeds have non-deep physiological dormancy. In contrast, seeds with deep physiological dormancy are not affected by gibberellin treatments and usually require more than 3 months of cold stratification to promote germination [4,46].…”

Arabidopsis ubiquitin ligase PUB41 is a positive regulator of the ABA response

“…Seed dormancy can be relieved with storage time of dry seeds, and can be reversed by stratification of the imbibed seeds at any time point (Bewley et al 2013). ABA is the primary hormone in maintenance of dormancy, and gibberellins (GA) are the key players in germination (Gianinetti 2023). Thus, the ABA to GA ratio determines the fate of germination.…”