BOTANY WITH BASICS OF HYDROBOTANY (AQUATIC PLANTS OF UKRAINE) - B.Ye. Yakubenko - 2011

VI. THE PLANT SYSTEM

LOWER SPORE PLANTS

GENERAL CHARACTERISTICS AND FEATURES

Order Oscillatoriales - Oscillatoriales

This order unites multicellular, filamentous, homocystous (lacking heterocysts) forms. Filaments are uniseriate, unbranched or falsely branched, with or without mucous sheaths, occurring singly or aggregated into bundles and mats (Fig. 12).

Trichomes are uniform and symmetrical, formed by monotypic Cells that are not differentiated in shape or function; occasionally, only the terminal cells differ in shape and feature thickened Cell walls. Reproduction occurs via hormogonia—short fragments into which the trichome breaks apart. Diagnostic features for Representatives of the Oscillatoriales include The Nature of the trichomes and the presence of mucous sheaths, as well as the degree of filament branching and their spatial arrangement.

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Fig. 12. General appearance of filaments in representatives of the Oscillatoriales:

A - Oscillatoria sp., Б - Artrospira platensis, В - Lyngbia sp.

The genus *Oscillatoria* is a typical inhabitant of freshwater bodies, marine environments, and soils (Fig. 12), capable of mass development and The formation of blue-green films and crusts that either float freely or encrust various substrates. Species of this genus are characterized by long filaments composed of uniform cylindrical cells, with only slightly distinct apical cells that sometimes feature a thickening known as a calyptra. The filaments are capable of specific rotational (oscillatory) movements, which involve the filament spinning around its own axis along with translational motion. The internal cell content is homogeneous or granular, occasionally containing gas vacuoles. Growth occurs through incomplete Cell Division, while reproduction results from the fragmentation of trichomes into few-celled segments—hormogonia (capable of active gliding movement) and hormocytes (non-motile). Toxic marine species capable of causing water "blooms" are also known.

The genus *Artrospira* is distinguished by filaments coiled into a regular, wide spiral (Fig. 12). Morphologically, it is similar to the previous genus. It is widely cultivated under industrial conditions for nutritional dietary supplements (with a protein content of up to 60–80% of dry weight) and used directly as food (Central Africa - Artrospira (Spirulina) platensis and Artrospira (Spirulina) maxima) as a natural biomaterial. This industrial raw material serves as the basis for manufacturing radioprotective and anti-allergic preparations, as well as products for normalizing METABOLISM, enhancing physical performance, and boosting Immunity.

The genus *Lyngbya* is morphologically close to the genus *Oscillatoria*, differing in that its cells are enclosed in a robust mucous sheath or envelope (Fig. 12). It grows in the benthos of standing freshwater and saline water bodies, occasionally in the water Column, within the mucus of other Algae, and in soil.