Elodea sounds like a name of a plant never seen before, doesn’t it? But you should know you have already seen it in an aquarium somewhere. 

Elodea (scientific name: Egeria densa, Egeria brasiliensis) is the general name given to these underwater weeds that belong to the group of the angiosperms. It is very used in aquarium vegetation and also in artificial pounds. It is common to find them in fishing stores. It is a monocotyledon from the Hydrocharitaceae family. 

People normally mix them up with “algae”, because they are similar-looking to some thin flat or tubular green algae, however Elodea belongs to the Kingdom of Plantae whereas most algae belong to Kingdom Protista. It allows us to say that Elodea has a set of features different from most algae, so they are placed in a different kingdom from the one most of the algae are included.    

Once it has a land vegetal adapted to aquatic environment, Elodea is considered an aquatic macrophyte. Macrophytes are very important to the balance of these environments, because they produce oxygen – that is released in the water, and they also serve as food for many species of fish, birds, and mammals. Besides they give shelter to small worms, as flatworms and planktonic organisms - micro-crustaceans and some types of mollusks.

Elodea is an angiosperm, because it has flowers in its reproductive period that, after fecundated, become fruits. However the main form of reproduction is by the fragmentation of the stem (which is very fragile).  In this type of reproduction, every fragment that comes off the stem develops and originates a new plant, which is a clone, because it has genetic material identical to that original plant. The reproduction of Elodea is very fast and happens very easily, what may be a problem in lakes and dams, due to the clogging of turbines in hydroelectric plants. 

 

Watching the leaves of Elodea, through an optical microscope, it is possible to notice an interesting process that happens inside their cells, the cyclosis (have you ever heard about it?). This phenomenon consists of a cytoplasmic chain, originated by the interactions between actin and myosin (cytoskeleton), that makes possible for the cell content to make a certain movement to let the chloroplasts better taking advantage of the light. Cyclosis also offers better distribution of molecular components of the cell (proteins, ions, water, and nucleic acids, etc.). Under a microscope, it is not possible to see the migration of proteins and ions because their dimensions are very small, but it is possible to check out the moves of the big organelles without using artificial coloring. 

Can you tell what vegetal organelle is possible to visualize without using any coloring? 

The visible organelles are the chloroplasts that can be observed in movement on the periphery of the plasma membrane and cell wall. With the incidence of light in the cell, the chloroplasts start moving. As they are stuck by the plasma membrane and the cell wall, the chloroplasts keep spinning all time.