Hornwort (Ceratophyllum Demersum)

Hornwort is probably the most uncaring aquarist plant ever. It does not even form roots and can float freely in e.B. breeding tanks. Its thin leaves provide protection for shrimp and juveniles. At the same time, it binds excess nutrients through rapid growth. Especially recommended at entry time!
Hornwort is excellent as a floating plant for the entry phase in the aquarium to avoid an algal bloom. ‘Foxtail’ is distinguished by narrower leaves and side shoots, which give the plant a pretty appearance.

hornwort-ceratophyllum-demersumHornleaf (Ceratophyllum), often known as the horn worm, is one of the best-known aquarium plants. Unfortunately, however, it is not one of the more pfle-like species. If it has established itself in an aquarium, it grows quickly. However, if the plants are taken to a different environment, they can dissolve very quickly. Baths in mineral water or tap water often lead to decomposition. Moving from one aquarium to another can also have this effect.
The reason for this is still unknown. However, it appears that, in addition to copper, cadmium, and pesticide and fish drug residues, many other factors trigger oxidative stress in the plant, leading to cell death. For example, extracts from oak leaves (Quercus robur) and reeds (Phragmites australis) cause stress at the cellular level. Within 24 hours, inhibition of photosynthesis can be detected by reducing the release of oxygen. The activity of various enzymes involved in cell detoxification during stress increases.

Increased levels of nutrients in the water also lead to stress in Ceratophyllum. As the nutrient content in the water increases, the surface of Ceratophyllum demersum shoots becomes increasingly uneven and large cavities form in the tissue (Xiong et al. 2010). Even at approximately 5 mg of nitrate and 0.6 mg of phosphate per liter of water, the tissue is interspersed with large holes. These structural changes will likely help oxygen and carbon dioxide to be transported better with increased metabolic activity.

Not all forms of nitrogen are well tolerated. Nitrate does not cause problems even at concentrations higher than 100 mg N / l (equivalent to approximately 440 mg of nitrate per liter). The limit value for urea is 15 mg N / l. Higher concentrations cause growth inhibitions and reduce the survival rate. Ammonium (NH3) has a particularly damaging effect. Values ​​above 0.41 mg / L already cause growth inhibitions and lead to death (FanYingZuo 2007).
Hornleaf needs a relatively large amount of light. The compensation point for Ceratophyllum demersum is 35 mol / m2 s-1 and the light saturation is reached at 700 micromol / m2 s-1. This corresponds to the light requirement of the Myriophyllum spicatum. Under good exposure, the bud tips of Ceratophyllum submersum also turn red in the aquarium.

The genus Ceratophyllum is the only one in the family ceratophyllaceae and in the ceratofilales. The species classification commonly used in aquaristics dates back to Wilmot-Dear (1985). In reviewing him, he recognized Ceratophyllumsubmersum and Ceratophyllumdemersum with four varieties each, which he distinguished by hand of morphological characteristics.

Meanwhile, however, extensive morphological, chemical, and genetic studies have shown that there are six species that fall into three sections. The Ceratophyllum section includes Ceratophyllumdemersum and Ceratophyllumplatyacanthum, the Submersum section Ceratophyllumechinatum and Ceratophyllumsubmersum and the Muricatum section the species Ceratophyllummuricatum and Ceratophyllumtanaiticum.
The species are distinguished according to the shape of the fruits and the degree of fork of the leaves.

However, the morphological differences are not always clear, because the fruits show a certain variability. At the top, however, there is always a more or less clear thorn, which is a remnant of the handle. Shoots are up to about 1 m long, rootless, and bear golden-brown leaves on trembling dichotomous leaves of 6 to 12 counts. Older stem sections are often bare and pull the buds down like an anchor. They tangle underwater on branches and between aquatic plants or are covered in mud, so the stems are more or less firmly anchored and grow vertically. The plants are usually present in shallow water. In crystal clear waters, however, they can grow to depths of eight or ten meters.

They live in nutritious standing waters, which can also be slightly brackish. In hard, alkaline waters, a white coating of lime forms on plants, which is released during the assimilation of carbon from hydrogen carbonate (biogenic decalcification). Duckweed (Lemna, Spirodela, Wolffia) often appear as complementary plants. Ceratophyllum species are true aquatic plants that flourish underwater and are pollinated by water. Male and female flowers are on the same plant. They sit apart from each other in the axes of the leaves. Female flowers are single and have a single fruit knot on a single strand at a time. The handle is long and thin and has the scar on the side.

Male flowers have 10 to 20 powdery leaves. When ripe, they separate and drift to the surface of the water. There they are spread by the wind and waves. When the pollen pockets open, the pollen clears, sinks down, and pollinates the female flowers that ripen underwater. Mainly, however, the propagation is carried out vegetatively by fragmentation of the shoots. We mainly know Ceratophyllum as an aquarium or pond plant. Because of their rapid growth, plants are popular as a biological agent against nutrient surpluses and algae.

Ceratophyllum contains substances that inhibit the growth of cyanobacteria. The horn leaf is used in bio-wastewater treatment plants. Even dried plants can be used to bind heavy metals from water. In naturopathy, Ceratophyllum demersum was used to treat dermatitis, elephantiasis, sunburn, fiber, or scorpion stings. The stems measure up to 3 m long. The shoots are green and the leaves feel very stiff and rough. The leaves are arranged in feathers. At the top, they are often very dense. They are divided once or twice (rarely three times) fork. Segments are serrated on the edge. The leaf feathers have a diameter of 1.5 to 6 cm. Segments are 1.5 to 2 cm long. The fruit is dark green to reddish brown and spineless 3.5 to 6 mm long and 2 – 4 mm wide. The surface is smooth or slightly knotted. The edges are not fused and spineless. At the base they usually have two straight or curved spines 0.1 to 1.2 cm long, which may also be missing. The spine at the tip is 0.5 to 14 mm long. Between June and October you can find flowers and fruits.
Among the fruits there are 10 to 14 flat bhighs with two spines at the top.

This species is widely used in aquariums. This horn leaf is relatively insensitive and is growing. However, too much ammonia and chloride or algae control agent residues are not tolerated. When inserted into an aquarium, the leaves can be lost. In some cases, the plants disintegrate completely. Propagation is carried out by lateral shoots. In the aquarium, sometimes male flowers form, but very rarely female ones. Fruits are almost never formed. The plant is very suitable as a spawning substrate and as a hiding place for females. The horned leaf is rootless and does not grow in the substrate. The stems rot when planted directly. However, the stems can be weighed with a piece of wood or other weight to keep them down. They should not be pressed into the substrate.