Australia: the largest plant in the world is an alga!



by LORENZO CIOTTI

Australia: the largest plant in the world is an alga!

A sensational discovery would have been made in Australia. Off the coast not far from Shark Bay, an amrin seaweed would live which has been believed to be the largest and most extensive plant on the planet. It would cover an area of ​​about 200 sq km.

It is Posidonia australis, and it provides habitat for many species, such as fish, turtle and dolphins. Jane Edgeloe of the University of Western Australia explained: "The plant spread using rhizomes in the same way a lawn can spread.

The current 200 sq km of ribbon grass lawn appears to have expanded from a single colonizing plant." Scientists who examined the grass samples found that they were not multiple Posidonia australis specimens, but a single plant.

The plant has found a way to survive in areas where the salinity is double that of other parts of the bay and can thrive in cold water temperatures of up to 15 ° C and warm up to 30 ° C.

Some curiosities about this particular alga

The leaves arise from orthotropic rhizomes, are ribbon-like, bright green in color that turns brown with the passage of time.

They reach a length of about 1.5 m, are 1 cm wide on average and have 13 to 17 parallel ribs. The tips are rounded and are often lost due to the action of waves and currents. They are organized in bundles with 6 or 7 leaves, with the oldest on the outside and the youngest on the inside The fruit, slightly fleshy and commonly called sea olive, is similar to a drupe and has a porous pericarp rich in an oily substance that allows it to float.

When it rots, a seed is released, covered by a thin membrane but without a real integument, which falls to the bottom and if it finds the right conditions of depth, stability and type of sediment, it germinates and gives rise to a new plant.

In order for the seedling to take root, it must find a humified substrate. Humification consists in the degradation of plant debris, so the plant can establish itself in soils previously colonized by other plants, such as macroalgae or other phanerogams.

Thus a real ecological succession is generated in which posidonia represents the last succession stage. Germination begins with the emission of a small white root from the radical pole and a leaflet from the apical pole. With sexual reproduction, the plant colonizes new areas, spreads the grasslands to other areas and guarantees genetic variability.