Derbesia is a type of green algae that belongs to the family Derbesiaceae. It’s a plant that has two different forms in its life cycle.
One form is called the sporophyte, and the other is called the gametophyte.
These two forms look quite different from each other, but they are both part of the same organism.
Who Discovered Derbesia?
The genus name of Derbesia is named in honor of Auguste Alphonse Derbès, a French naturalist, zoologist, and botanist. He was a Professor of Natural Sciences at the University of Aix-Marseille.
Derbesia was first known under different names for its sporophyte and gametophyte forms.
A German phycologist named Peter Kornmann was able to culture Derbesia in his laboratory and discover that both forms were part of the same life cycle of the organism.
What Are the Different Species of Derbesia?
There are many species of Derbesia, some of which are:
- Derbesia attenuata
- Derbesia boergesenii
- Derbesia corallicola
- Derbesia fastigiata
- Derbesia furcata
- Derbesia hollenbergii
- Derbesia indica
- Derbesia longifructa
- Derbesia marina
- Derbesia minima
- Derbesia novae-zelandiae
- Derbesia osterhoutii
- Derbesia pacifica
- Derbesia padinae
- Derbesia prolifica
- Derbesia rhizophora
- Derbesia sirenarum
- Derbesia tenuissima
- Derbesia turbinata
- Derbesia vaucheriaeformis
What Do the Two Forms of Derbesia Look Like?
The sporophyte form of Derbesia is a branched structure that can grow up to 3 to 5 cm tall. It has a brush-like appearance and grows from rhizoidal siphons.
The gametophyte form, previously thought to be a separate genus called Halicystis, looks like a round or pear-shaped vesicle.
It can grow to over 3 cm in diameter and has a short, thin stalk that anchors it.
What Are the Main Components of Derbesia’s Cell Walls?
The cell walls of Derbesia have different components depending on the form it’s in.
In the branched sporophyte form, the main component of the cell wall is a substance called mannan.
In the vesicular gametophyte form, the main component is a substance called xylan.
How Does Derbesia Reproduce?
Derbesia has a sexual cycle that involves both its sporophyte and gametophyte forms.
In the sporophyte form, it produces special structures called sporangia. These structures release stephanokontan zoospores, which have a ring of apical flagella, or hair-like structures, that help them move.
The gametophyte form produces gametes, or sex cells, that are released through small openings called papillae. These gametes are of two types, called anisogametes, and they have different sizes and shapes.
In some species of Derbesia, the life cycle involves a process called haplo-heterokaryotic.
This means that the gametophyte form has a single set of chromosomes, while the sporophyte form has two sets of chromosomes, one from each parent.
Nuclear fusion, or the joining of two nuclei, occurs in young sporangia right before the process of meiosis, which creates the zoospores.
There are also some variations in the life cycle of Derbesia. For example, sometimes, the larger gametes can produce new sporophytes without needing to fuse with another gamete. This is called parthenogenesis.
Another variation is when the vesicular gametophyte form grows directly from the sporangia without producing zoospores. New sporophytes can also grow directly from the zoospores.
Where Can Derbesia Be Found?
Derbesia has a wide global distribution and is found in waters ranging from the tropics to the Arctic.
The filamentous sporophyte form of Derbesia is found growing on protected stones or walls near the low-tide line, as well as on coarse algae, shells, or sponges at depths of up to 22 meters.
The vesicular gametophyte form is found at depths of up to 18 meters and may grow singly or in clusters on shaded underwater rock cliffs, in caves, under ledges, and on certain types of algae.
You can check out what this plant looks like over here.
|Required Water Flow:||High|