A Guide on Pteris

Pteris species can be found in the valleys and along the sides of roadsides in the North-Western and Western Himalayas. While P.cretica can grow up to an altitude of 2400 m starting from 1200 m, P.vittata can only grow at altitudes less than 1200 m. P.vittata grows at altitudes less than 1200 m. Its species in India include the following names: P.wallichiana, P.stenophylla, P. quadriaurita, P.pellucida, P.critica, P.vittata, and so on.

Plantae are the kingdom of classification.

1. Polypodiopsida is a class of animals.
2. Polypodiales is the order in which they are classified.
3. Pteridaceae is a family of plants.
4. Pteris is a genus of birds.

External Morphology of the Sporophyte

Pteris has a life cycle that is dominated by the sporophyte phase of the organism. It can be divided into three parts: the stem, the roots, and the leaves. The roots of this plant are black, slender, and wiry, and they emerge from the underside of the Rhizome. It can also be found on the surface of the water. The embryo gives rise to main roots, which have a short life span and are quickly replaced by adventitious roots as the embryo develops.

Branched and perennial underground stems, rhizomatous and ringed by brown scales, define the plant’s subsurface structure. A couple of the species have long-lasting leaf bases on their rhizomes, which is a unique feature. The upper section of the rhizome, which has a lengthy rachis, is where the leaves emerge. The base of the petiole is sometimes covered with brown scales, and other times with ramenta, depending on the species.

Acropetal pattern on the rhizome produces pinnately complex, microphyllous leaves that are arranged in an acropetal pattern on the stem. When compared to Pteridium, Pinnae has a higher rate of dissections. Some species have bipinnate leaves, digitate leaves, and decompound leaves, which are all types of leaves. Fronds are the leaves of a plant that have grown to a mature state. With the exception of the terminal leaflet, the rachis is composed of several sessile, coriaceous, lanceolate leaflets that are grouped in pairs.

Eventually, as they approach the apex, the leaflets become narrower, whereas they become wider as they approach the base. The leaflets in the middle of the rachis are the largest, while the size of the remaining leaflets decreases gradually toward the apical and basal regions of the rachis. Leaflets are rough and have a midrib, from which lateral veins extend in a dichotomous pattern, giving the plant its name. A dichotomous venation is visible in the open portion of the structure. Early leaves show signs of circinate vernation, which indicates that the plant is growing at a slow pace.

When viewed through a T.S. section, the rhizome is oval and divided into three layers: cortex, epidermis, and stele.

1. The epidermis is a single-layered layer of quadrangular cells that is covered with thick cuticles and is covered with cuticles.
2. Cortex — The cortex is divided into four to five layers of sclerenchymatous hypodermis, with the inner wide parenchymatous area separating the layers. The presence of leaf and root traces can be found in these areas.
3. Stele – The structure of this structure differs from species to species. In the ground tissue, a meristeles (annulus of vascular threads) has been discovered implanted (parenchymatous in nature). In each of these meristeles, the endodermis is composed of casparian strips within their radial walls, forming a single-layered elliptical structure. Under the epidermis, a 1-2 layered pericycle (with thin walls) is observed enclosing the phloem and encircling the capillaries. This organ has a central protoxylem that surrounds each side of the metaxylem and is placed in the same principle as the meristematic organ. The xylem parenchyma and tracheids are included in this group. Alternatively, the Phloem has phloem parenchyma and sieve cells on the other side. It completely encircles and protects the xylem.

Anatomy of a leaflet

The leaflet is made up of three layers: the mesophyll, the epidermis, and the vascular bundle. The epidermis is a single-layered layer that can be found on both the bottom and top surfaces. Stomata are found only in the lower epidermis of the skin. It is possible to discriminate between lower spongy areas and upper palisade or homogeneous regions in the mesophyll. 

Sclerenchymatous strips can be found on both the adaxial and abaxial sides of the midrib’s hypodermal regions, on both the adaxial and abaxial sides of the midrib. The midrib is surrounded by an amphicribral vascular bundle that is concentric and encircles a single layer of pericycle and the endodermis on either side. Implanted in the mesophyll are strands of vascular tissue.

Pteris reproduces mostly through vegetative and asexual ways, according to the species.

Asexual reproduction — occurs as a result of the development of spores. Because it produces only one type of spore, it is referred to as homosporous.

Vegetative reproduction – reproduction happens as a result of the death and decay of the older sections of the rhizome as the plant grows older. Branches and their main axis are removed and sprout as new plants as soon as the decay reaches the branching stage of the plant’s life.

Pteris has a life cycle that is similar to ours.

The coenosorus is responsible for the production of spores. The sporophyte is the main phase, and it is both autonomous and diploid in its development. Later, the spores germinate and evolve into the prothallus, which then advances to the gametophyte stage of development (haploid). Prothallus is characterised by its short lifespan, significant reduction in size, and independence. It reproduces sexually, with the assistance of archegonia and antheridia as a support. It is as a result of this that eggs and spermatozoids are created. 

Conclusion 

The fertilisation of the spermatozoa and the egg results in the formation of a diploid zygote, which is the future typical sporophyte.As a result, the life cycle has a diplohaplontic pattern. Because the alternation of generations is perceived as a variation in morphology in both the sporophyte and gametophyte, they are considered heteromorphic in this context.