* they depends on water for sexual reproduction
* their main plant body is Gametophyte(n)
* male sex organ- antheridium and female sex organ- archeagonium (flask shaped)
* Sphagnum(moss) provide peat (used for fuel and for packing material)
* sporophyte of bryophyte has three parts - foot, seta and capsule
There are two categories of bryophytes
1) Liverworts :- Thallus is dorsiventral and closely appressed to substrate
* asexual reproduction is by Gammae which is green, multicellular buds, developed in Gemma cup
* eg. :- Marchantia
2) Mosses :- having gametophyte with two stages, one is protonema developed from spores and other is leafy stage developed from secondary protonema and it also bears sex organs
* Vegetative reproduction is by fragmentation and budding in secondary protonema
* Sporophyte is more elaborate compared to liverworts
* Capsules contain spores
* eg. :- Funaria, sphagnum and polytrichum.
PTERIDOPHYTES :-
* Horestails and ferns
* first terrestrial plant having vascular tissue
* Main plant body is sporophyte (2n)
* Leaf are of two types 1) small-microphylls eg:- sellaginella. 2) Large - macrophylls eg:- fern.
* sporangia are on sporophylls which may form cones or strobilli eg. :- sellaginella, equisetum
* Gametophyte forms Prothallus(free living and very small)
* water is required for transfer of male gametes
* Types of Spores :- Homosporous(one type of spores only) and Heterosporous ( macro and micro spores eg. :- selaginella and salvinia).
Classes - 4 classes
a} Psilopsida - Psilotum
b} Lycopsida - Lycopodium, sellaginella
c} Sphenopsida - Equisetum
d} Pteropsida - Dryopsida, pteris and adiantum.
GYMNOSPERMS:
* having naked seed (ovule not enclosed)
* cycas roots having N2 fixing cyanobacteria is corolloid roots
* symbiotic relation between fungi and roots of pinus is Mycorrhiza
* All are heterosporous
* Sporophyll arrange spirally to form cone a} Male cone have microsporophyll. b} Female Cones have megasporophyll.
* Gametophyte is not free living and is highly reduced.
* eg. :- Cycas, Pinus, gingko, cedrus and sequia
ANGIOSPERMS (Flowering Plants)
* HAVING closed seeds enclosed within fruits
* pollen grain and ovule are formed within flowers
* smallest - wolfia
* Eucalyptus tree is over 100 metres long
Two Categories:- 1) Monocots :- having 1 cotyledon, parallel venation and trimerous flower. 2) Dicots :- having 2 cotyledon, reticulate venation and tetra Or penta-merous flower
* After fertilization, Ovule develops into seed and ovary develops into fruit.
Male reproductive organ is Stamen having anther and filament. Structure on anther called microsporangium forms microspores which develops into pollen grain (male gametophyte) having two male gametes
Female reproductive organ is pistil consisting of stigma, style and ovary. Ovary has megaspore mother cells forming megaspores which develops into embryo sac (female gametophyte)
Embryo sac is 7-celled and 8-nucleate having three antipodals cell, 1 central cell, 2 synergids cell and 1 egg cells. Central cell is having two polar nuclei as well. Polar nuclei(2n) fuses with one male gamete forming polar endospermic nuclei(PEN) is known as triple fusion. PEN develops into Endosperm.
Egg cell fuses with male gamete to form zygote known as syngamy. Zygote develops into Embryo.
* Since two fusions (syngamy and triple fusion) therefore called Double fertilization which is characteristic of angiosperms only.
* egg cell and synergids are together called egg apparatus.
Continue on next page:- click to read
By :- Educational Learning Knowledge
