In addition to normal spore reproduction, the roots, rhizomes and leaves of pteridophytes can produce new plants by means of asexual spores and apical meristem. Therefore, different propagation methods should be adopted according to different types of pteridophytes.
Ramet propagation is the most common and effective method for asexual propagation of pteridophytes. This method is mainly suitable for species with transverse stems or clumps. The process of plant division is very simple. After the fern is dug out, it is divided into two or more independent plants with sharp tools. Each small plant should have at least one bud, and the mother plant should have enough rhizomes. The subterranean stem of the fern spreads rapidly, and can be divided into several plants when new buds appear from early spring to early summer. The roots of Drynariaceae plants are always exposed to the surface of culture soil. Just cut the parts with enough roots and new buds, cut off the old leaves properly, and plant them in humus soil. New roots and new leaves will grow quickly. Ferns with aerial roots, such as Dryopteris fortunei, usually grow in clumps on trunks or rocks. Their rhizomes are thick and can store water. When they are divided, they should have enough roots. For the ferns with tufted or erect rhizomes, such as Dryopteris, Dryopteris, etc., they can be divided into two parts with a sharp blade and planted separately. Some special ferns, such as antler fern, will grow small plants on the roots or rhizomes. After the protective leaves grow, use a knife to cut off the small plants on the oldest protective leaves and take part of the base fern leaves. Fix them on the snake board or rotten board with iron wire to keep high humidity and make them grow again. After ramet, the plants need to be carefully conserved to facilitate the growth of new roots. It is necessary to cut off the oversized roots, dead leaves, petioles and injured parts of each part, and then plant them on the well drained substrate with proper shading to maintain the temperature and humidity. In particular, it is necessary to protect the new buds and unrolled leaflets, so that they can quickly resume growth under careful maintenance.
Fern
Some ferns have the ability to produce small plants on their leaves, which are called bulbils. The species with bulbils on the top of the leaves are Adiantum elongatum, Dryopteris simpliciformis and Dryopteris japonica. There are 2-3 mature bulbils in each plant. If the arcuate bullet falls to the ground, it will form a small plant. When the small plant grows up, it can grow bulbils again. It can cross the ridge if it propagates continuously, so it is named as a fern. The species of small plants scattered on the veins of leaves are Polystictus. The veins with small plants can be cut off in sections and planted in the soil mixed with sand and humus (3:1). The viviparous fern and the spore fern have bulbils on the leaf surface. The bulbils attached to the mother plant can obtain sufficient water and nutrients from the mother plant. Generally, when they grow to a certain size, it is best to take root before they are separated from the mother plant. At this time, the survival rate of reproduction is high. It can be planted in the substrate mixed with sand and peat soil. Do not bury it too deep. Cover the basin with glass plate or plastic film to keep the air humidity. Some people fix the mother's bulbils on the soil surface with the help of a wire ring to make them grow into small plants naturally, and finally separate them from the mother to become independent plants.
Similar to the bulbil is the spore, which is also a kind of asexual bud on the leaf, and is unique to pteridophytes such as Pinellia and epiphytic Lycopodium. In the process of gametophyte development, a group of small spores are produced. When they mature, they will spread with the rain and grow on the bark or soil.
Many ferns can grow stolons similar to roots on the lateral branches. Most of the stolons are terrestrial. The stolons of NEPHROLEPIS are aerial and often suspended in the air. They can grow into small plants only when they fall to the ground and touch the soil. The stolon will extend from the mother to the surrounding. If it is covered with soil, new buds and roots will be produced. The newly grown plantlets need to continue to absorb water and nutrients from the mother plant, so they should not be separated from the mother plant in a hurry. When they can survive independently, they can cut off the stolon near the mother plant and move the plantlets to the new culture conditions. Generally, the survival rate is the highest in spring and summer.
Layering is a good method for some special ferns. For example, for spike like Pinus tabulaeformis and climbing ferns such as haijinsha, cover the growing part with mixed soil, and the budding eye will take root. After the growth is good, it can be separated. Some species of Drynariaceae have long rhizomes above ground, which can be compressed by air. The wet humus and moss are wrapped on the stem with plastic film. After 2-3 months, the roots begin to form. When the roots are full, they are cut and transplanted from the main stem to become new plants. Opposite ferns can also be propagated by layering method. The mature old leaves close to the rhizome are removed, and the dead substances are removed. They are placed in the mixed soil of sterilized sand and peat soil (3:1). The planting trough is covered with glass or film. Under warm and shady conditions, new buds will appear in 1-2 months. When they grow good roots and leaves, they can be moved to the basin. This method of approximate cutting is very practical.
Tuber is an abnormal structure formed by the enlargement of underground root or stolon, which has the function of storing nutrition and regeneration. There are few ferns with tubers, and the most representative is NEPHROLEPIS. Tubers are usually crowded on the rhizomes. The tubers of Dryopteris NEPHROLEPIS are oval or spherical, 1-2 cm in diameter. When young, the outer skin has bright white scales. When mature, they are brown. The tubers are fleshy, white and full of water. The tubers of Dryopteris NEPHROLEPIS grow on the wire like stolons. When propagating, the tubers with some stolons can be cut and transplanted into the loose and permeable soil, and the new plants can grow quickly.
There are many ways of asexual propagation of ferns, such as rosette ferns can also be propagated by ear. Some species of Lycopodium can propagate through stem tips. The method of tissue culture can be used to propagate the rare and endangered ferns and the hybrids that produce sterile spores.