Characteristics of different phyla of plantae.
Do you want to know the characteristics of different phyla of kingdom plantae? In this article you will find the characteristics of algae, bryophytes, pteridophytes, gymnosperm and angiosperms. To know the characteristics of different phyla of plant kingdom, please read this article.
The beautiful earth is full of variety of organisms. All the organisms which are eukaryotic, multi-cellular and photosynthetic have been included in kingdom Plantae in five kingdom classification. Plants exhibit a great diversity in their structure, nature and life styles. All of these are characterized mainly by the presence of cell wall and green photosynthetic pigments called chlorophyll. As far as their body organization is concerned, plants have wide range of forms starting from filamentous algae to a giant banyan three. Plants are always multi cellular and developed autotrophs, therefore this kingdom may also be known as the kingdom of complex autotrophs. The kingdom plantae is divided into five sub groups:
- Phylum – Algae
- Phylum – Bryophyta
- Phylum – Pteridophyta
- Phylum – Gymnosperms
- Phylum – Angiosperms
Characteristics of phylum algae
The term algae has been derived from a Latin word alga means seaweed. Algae contains near about 18,000 genera with 29,000 species. In two kingdom classification algae were included in thallophyta because algae have thallus like body, I.e., body is not differentiated into root, stem and leaves. Branch of biology which deals with the study of algae is called as algology or Phycology. The famous botanists F.E. Fritsch is known as the father of phycology. Likewise Dr. M. D. P. Lyenger is regarded as the father of Indian phycology. The important characteristics of algae are:
- The plant body is thallus like or thalloid which is not divisible into root, stem and leaves.
- Chlorophyll is found in the body cells, hence algae manufacture their food material of their own. Hence, algae are autotrophs.
- Plant body does not contain vascular tissues.
- Algae are mainly hydrophytes. It means algae are aquatic plants and found in water.
- The cell wall of algae are made of cellulose.
- In the life cycle of algae, sexual, asexual and vegetative mode of reproduction are found.
- After sexual reproduction zygote is formed but it does not give rise to embryo.
- In most of the algae alternation of generation is not found. Gametophytic stage is dominant and sporophytic phase is limited to zygote only.
- Algae possess unicellular reproductive organs, which are without jacket.
- The reserve food material of algae is starch.
Characteristics of Bryophyta
Bryophytes constitute the primitive group of non vascular plants in which plant body is in the form of thallus. However, root, stem and leaf like structures may be found in bryophytes. Bryophytes are regarded as the primitive group of plants that have inhabited land after migrating from the aquatic environments. Bryophytes are also regarded as the amphibians of the plant kingdom as they can inhabit both aquatic and terrestrial habitat and require greater amount of moisture for completion of their life cycle. The main characteristics of bryophytes are given below:
- Most of the bryophytes are land dwellers. However few of bryophytes are aquatic, e,g, Riccia fluitans. Bryophytes are often found in damp and sandy habitats and found to grow during rainy season forming green carpets or mats on damp soil, rocks, walls, tree trunks, etc.
- Plant body of bryophytes is bilaterally symmetrical , branched and leaf like which bear root hair like structures known as rhizoids on the ventral surface.
- The body of some bryophytes is radially symmetric which isdifferentiated into rhizoids, stem and leaves.
- Bryophytes are non vascular land plants, i.e., bryophytes lack xylem and phloem characteristic of higher plants.
- The plant body is prostrate, simple and thallus like in lower form like Riccia and leafy and erect in mosses.
- The gametophyte is the dominant phase of the life cycle. Gametophyte is independent and concerned with sexual types, male antheridium and female archegonium.
- There is complete absence of true roots, stem or leaves.
- Reproductive organs are multi-cellular and found surrounded by sterile jacket layer. They are of two types, male antheridium and female archegonium.
- Fertilization takes place in presence of water.
- After fertilization embryo is formed inside archigonium. The embryo developed into a sporophyte.
- Sporophyte partly depend on gametophyte.
- The sporophytic pahse has a short life span and sporophyte is mainly concerned with the production of asexual spores which germinate to produce new gametophytic plant.
- There is a remarkable tendency of the gametophytic and sporophytic phases to alternate with each other. This biological phenomenon is called alternation of generation.
Characteristics of Pteridophyta
Pteridophytes are the first terrestrial plants to invade on land. These are popularly known as vascular cryptogams as they contain vascular tissues (xylem and phloem) but are always devoid of flowers and seeds. Pteridophytes show well advancement over bryophytes, The group includes over 10,000 species most of which are found in moist and shady places. The main characteristics of pteridophytes are:
- The main plant body is sporphyitc, usually differentiated into roots , stem and leaves.
- The dominant phase of life cycle is sporophyte.
- Pteridophytes are vascular plants. The conducting tissues, the xylem and phloem are well developed.
- Xylem lack vessels and phloem lack companion cells.
- Sporophyte produces spores, which germinates to produce gametophyte.
- The spores are produced in special sac like structures called sporangium.
- She sporangia in some cases form compact spore producing strobilus or cone.
- The gametophytic phase is of short duration and is concerned with the production of sex organs and gametes.
- Sexual reproduction is oogamous. The male sex organ is call antheridium and female sex organ is called archegonium.
- There is a clear-cut alternation of sporophytic (2n) and gmaetophytic (n) phases in their life cycle. The phenomenon is called alternation of generation.
Characteristics of Gymnosperms
Gymnosperm includes 900 species. As the name suggests, the gymnosperms, are the naked seed plants, as they have no coverings and the ovules are freely exposed before and after fertilization. The seeds of the gymnosperms are exposed on a modified leaf called sporphyll. Gymnosperm is an intermediate group standing in between pteridophytes and angiosperms. The main characteristics of gymnosperms are given below:
- Plant are perennial, woody trees or shrubs and xerophytic in nature.
- Gymnosperm includes vascular, naked seed plants.
- Vascular bundle consists of xylem and phloem but the xylem is devoid of vessels and phloem that of companion cells.
- Reproductive parts of gymnosperms are in the form cones or strobilus.
- Male cone contains several microsporophylls with microsporangia on their undersurface. Female cone contains many megasporpphylls with one to several naked ovules.
- Inside the microsporangia microspores or pollen grains are formed by meiosis division of special cells, which germinate toproduce male gametes.
- Female gametophyte develops inside the ovule and contains two or more archegonia at the anterior end.
- Pollination is anemophilous, i.e. wind pollinated.
- Pollen grains germinate to form pollen tube on female cone after pollination and produces male gametes which fuses with female gamete to form zygote. Embryo develops from zygote and ovule along with embryo forms seed, which germinate to form new plant.
- Secondary growth is present.
- Usually polyembyons is found in seed.
- Embryo bear two or more cotyledons.
Characteristics of angiosperms
Angiosperms are closed seed pants. Angiosperms are the highly developed plants bearing flowers and have distinct accessory and essential whorls. Angiosperms exhibit wide diversities as regards their form and structure, ranging from smallest duck weeds to the huge forest trees. There are over2,50,000 species of angiosperms. The main characteristics of angiosperms are:
- Plant body is differentiated into root, stem and leaves.
- Plant body is sporophytic which is generally independent and alternates with gametophytes depend upon the sporophyte.
- Reproductive organs of angiosperms is a flower having four whorls viz. calyx, corolla, androcium and gynoecium.
- Haploid stage is reduced.
- Seeds are covered within ovary.
- Process of double fertilization is found in angiosperms.
- Vascular system is well developed.
- Xylem consists of vessel, trachied, xylem fiber and xylem parenchyma and phloem consists of sieve tube, companion cell, phloem fiber and phloem parenchyma.
- Angiosperms may be parasitic, saprophytic, epiphytic, insectivorous and outotrophic.
- Angiosperms are well adapted for their environment.
So, dear friends, these are the characteristics of different phyla of kingdom plantae. Hope this article will help you in your study.