Thallus is ... The structure and types of thallus

Algae and lichens do not have many similar features. But this is only at first glance. The most important of them is how their body is arranged - the thallus.

Types of multicellular organisms

It would seem, what can differ organisms, consisting of a dozen or more cells? However, depending on the characteristics, their body can have a fundamentally different structure. For example, in higher plants, cells similar in structure and function are grouped together to form tissues. Each of them has its own structural features, which are closely interrelated with the functions performed. For example, a leaf of plants is formed by an integumentary, basic storing and photosynthetic, conducting and mechanical tissues.

But the volvox organism is also formed by a multitude of cells. However, each of them functions separately. These cells are not specialized. They are surrounded by a common shell, forming colonies.

What is thallus

Thallus is a structure that also consists of a multitude of cells. They are identical in structure, and each works as a separate organism. Talloma cells fit tightly to each other, therefore visually their combination creates the appearance of an organism consisting of tissues and organs. In fact, these structures are only representatives of higher plants, which have a leaf-building structure.

Types of thalli

Thallus, slant, thallus are all names of the vegetative body consisting of the same cells. They are quite diverse. Filamentous thalluses share in one plane. They represent one or more rows of cells. Similar structures are typical for cyanobacteria and various parts of algae - green, brown and ochrophite. If individual threads join together, a false-tissue thallus is formed. It is quite voluminous and occurs in representatives of brown and red algae. But the fungi most often observed are mycelial thalli. They consist of separate threads - hyphae. Their totality forms entire fruit bodies of fungi. Yeast-like thallus consists of individual cells or their decaying chains. This structure determines its ability to budding.

There are also single-celled thalli. So scientists call monadic or flagellate cells of zoospores of algae and sex cells of animals. Amoeboid thalli are widely distributed in nature. This group includes cells of certain algae groups capable of forming pseudopodia or pseudopods.

Which organisms have a thallus

As you can see, the tallom structure is characteristic only of certain representatives of wildlife. These include all parts of algae, lichens and fungi.

The thallus also has higher spore plants at the sprouting stage. For example, in ferns it looks like a small plate, on which sex cells develop over time. When they merge, a zygote is formed - a fertilized egg. From it, a green leaf-and-stem plant develops, which is an asexual generation of fern-like plants.

Thallus of fungi, algae and lichens is characterized by its individual level of organization and functioning. Let's consider each of them in more detail.

Thallus of algae

Algae are the very first plants on the planet. Dwelled in water, they do not need real tissues. These are typical tallom organisms, widely distributed on Earth and having a wide range of uses. In addition to the thallus, the algae have another multicellular structure. These are rhizoids, partially fulfilling the function of roots, but also not forming tissues. A typical organism with such a structure is laminaria - thalli, the reviews and descriptions of which are known to all. In everyday life, this algae is also called sea kale and is eaten due to its valuable nutritional qualities.

Types of thallus lichens

These tallom organisms are a unique symbiosis of fungi and blue-green algae. The structure of the thallus of lichen is represented by separate hyphae, between which are scattered cyanobacterial cells. A crust forms above and below this formation. This is a dense layer of hyphae of fungi. Depending on the shape of the thallus lichens are leafy, scaly or bushy. And this type can be easily identified with the naked eye. Thus, scale lichens are crusts that closely fuse with the substrate. Most often they grow on rocks or rocks. Leafy lichens have a lamellar body with a wavy edge. Their thallus is attached to a substrate, which can be wood, stones or soil, with the help of a short leg. Bushy lichens usually have branched thalli. They can grow both on soil, and branches of large trees and stony base. Coloring lichens is very diverse: white, yellow, blue and even black.

Features of life activity

The thallus is primarily a vegetative body of organisms that carries out the process of asexual reproduction. In many species of algae there is a process of alternation of generations. And the sporophyte prevails in their life cycle. This generation, which multiplies asexually by dividing cells and separating parts of the thallus. Nutrition of thallus of different types depends on the features of their structure. For example, lichen hyphae fungi suck water with dissolved nutrients from the soil, and cyanobacteria cells are capable of photosynthesis. Algae are also autotrophs. But the fungi carry out only soil nutrition, sucking the water with hyphae.

The value of thallus

The peculiarities of the thallus structure make its owners rather unpretentious and widespread organisms, which often possess valuable properties. For example, kelp. Thallus, the reviews of which are known to everyone, are valuable fruit bodies of mushrooms, and thalli of lichens. They are a source of food for many species of animals and even humans, because they are rich in proteins and trace elements. There is an opinion that even the manna of heaven, which the Almighty sent to people, is nothing but one of the species of lichens.

The main function of this structure for organisms is vegetative reproduction. Individual parts of the thallus can separate, giving rise to young organisms. With the help of the thallus, the process of feeding takes place. The thalli of algae and lichens provide them with organic substances that are formed during photosynthesis. They are also important suppliers of oxygen on the planet. Hyphae of fungi are able to enter into mutually beneficial cohabitation with the roots of trees, called mycorrhiza. Bright examples of such organisms are poderezovik and podsinovik. The surprising fact is that the plant with mycorrhizas receives several times more water from the soil than the same tree without it.

So, the thallus is the structure that forms the body of algae, fungi and lichens. It consists of individual cells and does not form specialized tissues. Therefore, the body of these organisms is not divided into separate organs. In algae, the rhizoids do not function as roots, they also do not form tissues, and thallus of fungi is formed by separate filaments - hyphae. The main function of the thallus is asexual reproduction and nutrition of organisms.