Seed as a Propagation Material : Seed size and Chemical Composition and their relevance in Seed Germination

Seed as a Propagation Material: seed size and chemical composition and their relevance in seed germination

1. Seed as a Propagation Material: seed size and chemical composition and their relevance in seed germination Seeds are the primary means of propagation for many plant species, playing a vital role in the continuation and dispersal of plant life. They contain the embryo, endosperm, and protective structures that enable the plant to germinate, establish, and thrive in diverse environments .

2. Seed Size and Its Relevance in Seed Germination Seed Size Relevance in Germination Large Seeds Typically have more stored food reserves, enabling faster and more robust seedling emergence and establishment. Small Seeds May have limited food reserves, but can often germinate and establish in a wider range of conditions. Seed size is an important factor that influences the seed's ability to germinate and the subsequent growth of the seedling. Large seeds generally have an advantage in terms of available energy reserves, while small seeds can adapt to a wider range of environmental conditions .

3. Seed Chemical Composition and its Role in Seed Germination Stored Reserves Seeds contain a rich assortment of carbohydrates, lipids, and proteins that serve as essential energy sources for germination. Phytohormones Hormones like gibberellins, cytokinins, and auxins regulate various stages of the germination process, from dormancy to radicle emergence. Seed Coat Compounds Phenolic compounds, lignin, and other substances in the seed coat can influence water uptake and act as germination inhibitors or promoters .

4. Physiological Mechanisms Regulating Seed Germination Imbibition The initial uptake of water by the seed, triggering the activation of metabolic processes necessary for germination. Hormone Signaling Gibberellins and other plant hormones regulate the mobilization of stored reserves and the weakening of seed coats. Enzyme Activation Germination involves the activation of enzymes that break down storage compounds, providing energy and nutrients for the embryo. Cell Elongation The radicle and cotyledons undergo rapid cell expansion, leading to the emergence of the seedling from the seed.

5. Biochemical pathways involved in seed germination Metabolic Activation Seed germination triggers a cascade of metabolic processes, including the breakdown of stored nutrients and the activation of biosynthetic pathways to provide the energy and building blocks for growth . Hormonal Regulation Plant hormones like gibberellins and abscisic acid play a crucial role in regulating the biochemical events that control seed germination and dormancy . Mobilization of Reserves The breakdown and mobilization of stored carbohydrates, lipids, and proteins in the seed provide the necessary nutrients to fuel the initial stages of seedling growth and development.