Hello, Readers!
Let's have a look at the Plant Kingdom.
Plant kingdom includes algae, bryophytes, pteridophytes, gymnosperms anda angiosperms
ALGAE
Algae reproduce vegetatively by
fragmentation, asexually by formation of different types of spores and sexually by formation of gametes.
Depending on the type of pigment
and stored food, algae are classified into three classes, namely Chlorophyceae, Phaeophyceae and Rhodophyceae.
Eg: Green algae (i) Volvox (ii) Chlamydomonas (iii) Chara
Brown algae (i) Laminaria (ii) Fucus (iii) Dictyota
Red algae (i) Porphyra (ii) Polysiphonia
BRYOPHYTES
Bryophytes are plants that live on land but are dependent on water for
sexual reproduction. Their body is more differentiated than that of algae.
They possess root-like, leaf-like and stem-like structures.
The bryophytes are divided into liverworts and mosses.
Eg: Liverworts – Marchantia, Riccia
Mosses – (c) Funaria, Sphagnum
PTERIDOPHYTES
In pteridophytes, the main plant is a sporophyte which is differentiated into true root, stem and leaves. These organs possess well-differentiated vascular tissues The sporophytes bear sporangia which produce spores. The spores germinate to form gametophytes. The gametophytes bear male and female sex organs called antheridia and archegonia, respectively.
Eg: Ferns, Seleginela
GYMNOSPERMS
The gymnosperms are the plants in which ovules are not enclosed by any
ovary wall. After fertilisation the seeds remain exposed and therefore these plants are called naked-seeded plants. The gymnosperms produce microspores and megaspores which are produced in microsporangia and megasporangia borne on the sporophylls.
Eg: Cycas, Pines
ANGIOSPERMS
In angiosperms, the male sex organs (stamen) and female sex organs (pistil) are borne in a flower. One male gamete fuses with egg cell
(syngamy) and other fuses with diploid secondary nucleus (triple fusion). This phenomenon of two fusions is called double fertilisation and is found only in angiosperms. The angiosperms are divided into two classes – the dicotyledons and the monocotyledons.
Eg: Peas, Rose, Neem tree etc
Wheat, Maize, Bajra etc
