No nutrient and water penetration into the sporeĮxogenous dormancy: This kind of dormancy is due to external factors like temperature and pH variation, desiccation, the absence of light etc.Production of a certain germination inhibitor.Some internal and external factors can affect dormancy.Įndogenous dormancy: This kind of dormancy is due to internal factors like: The dormancy is characterized by no cytoplasmic movement and decrease or no metabolic activity. Dormancy is subdivided into the following two types:ĭormancy of spores is generally a stage, in which a spore remains in a resting or dormant state, where it is metabolically inactive. It is the mechanism that prevents the germination of the spore into a new vegetative cell, during the unfavourable conditions. These exospores then go through the maturation phase and detach after its development.The outer and inner coat develops, resulting in the exospores.This bud then grows and forms a double-layered membrane outside itself.Then, a small protuberance develops outwards called “Bud”.First, the cytoplasmic division occurs in the vegetative cell.Exospores sporulates through the following steps, which are given below: Sporulation of exospore: Exospore forms outside or on the vegetative cell surface. A release of endospore: After the maturation, the fully developed endospore releases out of the vegetative cell, and later germinates into a new individual.Maturation of endospore: Then, the maturation of endospore occurs.Spore coat formation: After that, spore coat forms around the endospore.Cortex deposition: Then, a cortex of calcium and dipiclonic acid deposits between the membrane.Then, the vegetative cell’s DNA disintegrates. Vegetative DNA disintegration: Cytoplasmic membrane first grows and then engulfs forespore within the second membrane.Cytoplasmic membrane invagination: After that, the cytoplasmic membrane invaginates to form a forespore.DNA alignment: Then, the alignment of DNA occurs along the cell long axis.DNA – Replication in the vegetative cell: First, replication occurs inside the vegetative cell, by which a replica of genetic material (DNA) forms.Some steps are involved in the sporulation of endospore, which is as follows: It takes about 8-9 hours, for the sporulation of endospore. Sporulation of endospore: In this, one vegetative cell forms a single spore, which later germinates into a new vegetative cell. Sporulation is also called “ Sporogenesis”. It is the phenomena of the spore formation by the vegetative cells. The life cycle of spores involves the following three events: Central core consists of structural components mainly DNA, RNA (small amount), 40% dipiclonic acid (DPA) etc.Germ wall protects the central core of spores from the potentially damaging chemicals.Its primary function is to protect against dehydration and high temperature. Cortex is the region that lies between the inner and outer coat and is made up of peptidoglycan.The outer and inner coating is made up of proteins, and its main function is to provide resistance against the chemical and enzymatic actions to the spores.It consists of the following structural components, which you can see in the diagram that is given below. Endospores are the spores that form within or inside the vegetative cell, while exospores are the spores that form outside the vegetative cell. Spores are broadly classified into two types, namely endospore and exospore based on their position. Spores form new individuals through mitotic cell division once they germinate. In its dormant state, the spores are highly resistant to adverse conditions. Thus, the spores are generally haploid cells that are produced by meiosis. It provides the asexual means of reproduction, in which the spores do not need to fuse, unlike gametes. Spores can be defined as the reproductive structures, which are usually single-celled. In this context, we will discuss the different cytological events or life cycle of a spore along with its definition, types and structural components. Spores disperse through the wind or air current. These are the reproductive structures that form in the life cycle of many plants, fungi, bacteria etc.

Spore formation