Seed Dormancy and After-ripening Mechanisms in Seed Germination: A Comprehensive Review

Abstract

A review on seed dormancy and after-ripening mechanism on seed germination was conducted. After-ripening is an important post-harvest phase in seeds that causes physiological and biochemical changes that reduce dormancy and promote germination. It is a time based and environment regulated process that occurs in dried seeds and determines germination potential. This post-harvest period is characterized by a series of biochemical and molecular changes that modify the seeds internal environment, ultimately breaking dormancy and enabling germination. The process of after ripening is mediated by several key mechanisms, including hormonal balances, particularly the reduction of abscisic acid levels and the increase in gibberellins and reactive oxygen species serve a dual function in both signalling and oxidative damage repair, contribute to dormancy associated barriers. Unlike other dormancy breaking methods, such as stratification, which requires external factors like light or temperature fluctuations, after-ripening primarily occurs under dry storage conditions. Molecular studies have shown that after-ripening involves gene expression with transcriptional regulation of dormancy related genes and activation of germination promoting genes are observed. Epigenetic modifications, such as DNA methylation and histone modifications also contribute to the regulation of these genes during after-ripening. Understanding the after-ripening mechanism is very important for improving seed storage, enhancing germination rates and optimizing crop yields and helps in management of seed banks, minimizing unwanted in-situ germination before harvest and also elucidates the complication of seed dormancy and germination, providing valuable information for both basic plant biology and applied agricultural sciences. Hence, understanding the interaction of external factors, internal seed biology, and after-ripening conditions are critical for optimizing seed germination rates and crop productivity.