Give an account of structure, reproduction and life history of Batrachospermum

It is fresh water red algae and belongs to class Rhodophyceae and normally lives in cool, well aerated clear and shady situations. Plant body is filamentous freely branched and gelatinous in texture. Plant is like a chain of delicate beads. Each bead consists of a whorl of densely branched laterals of limited growth. Main axis consists of single row of elongated cells placed one above the other. From main axis arise branches of unlimited growth. Also node cells give rise to filaments which grow downwards the next node covering the axis cells forming pseudo cortex. Each cell of filament consists of two layered cell wall outer of pectin and inner of cellulose, cells are unimucleaet and contain a large number of parietal chromatophores, each with a single pyrenoid. Growth takes place by an apical cell.

Reproduction: It takes place by sexual method.
Sexual reproduction:

It is advanced oogamous type. Plants may be monoecious and dioecious. Male reproductive organ is antheriduim and female reproductive organ is called carpogonuim.
The antheriduim (Spermatogonuim) is a spherical or oblong unicellular structures which arise at the distal ends of short laterals. They arise in large numbers. Each antheriduim produces a single non-motile spermatuim (male cell) the spermatia are unimucleate and probably have same specific gravity as that of surrounding water. Therefore they remain floating.

The capranguim or procarp consists of a swollen basal portion with an egg and a narrow elongated neck like trichogyne. The caprogonia arise terminally on the laterals. The constricted portion of caprogonuim separating the trichogyne from the basal swollen portion known as plug. The caprogonuim develops at the tip of the caprogonial branch which is usually 3 to 4 celled. The terminal cell of caprogonal branch enlarges and becomes flask shaped. The single nucleus of terminal cell forms the egg.
Fertilization: The spermatia on liberation are carried away by water to trichogyne at the point of contact of spermatia disorganize and the nucleus of the spermatium passes down into carpogonium and fuses with its nucleus. A wall develops at the base of corpogonium and zygote is formed .

Germination of zygote:
The nucleus of diploid zygote increases in size and divides meiotically into two daughter nuclei lying one above the other. One of the nucleus migrates into a lateral protrusion which develops to the side of carpogonium and is cut off by wall and form gonimoblast initial which develop gonimoblast filament.

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