Characteristics of different phyla of plantae.

Introduction

1. Phylum – Algae


2. Phylum – Bryophyta


3. Phylum – Pteridophyta


4. Phylum – Gymnosperms


5. Phylum – Angiosperms

Characteristics of phylum algae

• 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

• 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

• 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

• 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

• 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.