Seed Filling

Abstract

The synthesis of seed storage reserves occurs during seed filling, and many seeds contain large and characteristic levels of polymeric reserves. Storage reserves are found in the endosperm of cereal seeds and in the endosperm and/or cotyledons of dicot seeds depending of the plant crop species. Recently progress has been made in understanding the complex network of genetic regulation associated with seed filling. These advances in storage reserve quantity and nutrient quality contribute to a comprehensive understanding of reserve composition, synthesis, and regulation. Phytohormones such as abscisic acid (ABA), cytokinin, gibberellic acid, Indole-3-acetic acid (IAA), ethylene and their interactions play critical roles in seed filling and development. At different stages of seed development, the levels of different hormones such as ABA, IAA zeatin and zeatin riboside changes gradually from the beginning of the process to maturity. In addition, the quality and yield of seed storage reserves are significantly affected by the environmental conditions before and during the synthesis of the reserves. Given the fateful importance of seed storage reserves for food and feed and their use as sustainable industrial feedstock to replace dwindling fossil reserves, understanding the metabolic and developmental control of seed filling will be an important focus of plant research.

Temporal and spatial transcriptional regulation of phytohormone metabolism during seed development in barley (Hordeum vulgare L.)

“…The detection of relatively high levels bioactive GAs in both embryo and endosperm tissues at the early stage of SF may implicate their contribution in controlling embryo development, differentiation of proliferating cells into specialized cells, organ expansion and SF ( Sabelli and Larkins, 2009 ; Domínguez and Cejudo, 2014 ; Sercan et al., 2022 ). However, the levels of bioactive GAs were much higher in the endosperm than embryo during SF phase, reflecting the major role they play in regulating endosperm growth and accumulation of storage reserves.…”

“…The detection of relatively high levels bioactive GAs in both embryo and endosperm tissues at the early stage of SF may implicate their contribution in controlling embryo development, differentiation of proliferating cells into specialized cells, organ expansion and SF (Sabelli and Larkins, 2009;Domıńguez and Cejudo, 2014;Sercan et al, 2022). However, the levels of bioactive…”

“…ABA level in seeds is controlled by a balance between its biosynthesis and catabolism, which are regulated mainly by the actions of 9- cis -epoxycarotenoid dioxygenase (NCED) and ABA 8’-hydroxylase (ABA8’OH; encoded by CYP707A genes), respectively ( Nambara et al., 2010 ; Tuan et al., 2018a ). GAs are also known to regulate several seed developmental processes such as embryo development, cell differentiation and SF ( Sercan et al., 2022 ). For example, GA deficiency leads to increased rate of seed abortion or significant reduction in embryo and seed growth rate ( Swain et al., 1995 ; Swain et al., 1997 ).…”