PTERIDOPHYTES

PTERIDOPHYTES 

LET'S DISCUSS ABOUT PTERIDOPHYTA

• Study of pteridophytes called pteridology.
• They are known as reptiles of plant Kingdom. 
• It is the first vascular plant (means xylene and phlegm are present)
• Vesicle in xylem &, companion cell in phloem are absent.
• Pteridophtye are called the first successful terrestrial plant (I.e. they are more adopted terrestrial plant as compared to other bryophyte because having vascular tissue or root.)
• Grown in cool, shady, &moist places.
• Plant body is differentiated stem is underground known as Rhizomes.
• Stem is erect or prostrate.
• On the basis of leaf pteridophtyes are of two types:-

1. In which stem is smaller, elwhile leads are large. They are known as macrophyllaus.  (Megaphyllous, pteridophytes.) E.x:- Ferm
2. Stem is larger and leaf are smaller they are called (microphyllus pteridophytes). E.x:-Selaginella.

Life Cycle of Pteridophytes

1. Main plant body is diploid, (Sporophyte) (because it is diplohapooid means diploid phase is more than haploid

°We know that sporophyte is (2n) and gametophyte is (n) so, it's main body is diploid that's why it is sporophyte

2. Most of the pteridophyte are homosporous (means they produce only one type of sporo during reprodu tin.)

3. Formation of sporo takes place in sporpngia. Sporongia are formed on the surface of sporopohylls
Note:-sporophylls:- The leaf's on which sporogia are formed
Trophophylls:- Normal photosynthetic leads.
On sporophylls sporogia are formed in group, the group of sporongia known as sorus (sing:-sori)
4. Spore mother cell present in sporongia. Spores are formed by these spores mother cell through meiosis and the spores starts the gametophyte generation.
5. The germination of spore 8s excosporic.
6. In soil a gametophyte is formed by the germination by each spores known as prothallus.
7. The formation of gametophyte (Prothallus) takes places in the soil therefore it is free independent or amyotrophic.
8. There is no dependency b/w the main saprophytic plants and this gametophyte.
9. The gametophyte is small but multicellular less develop, free living, mostly photosynthetic, tabloids and non-vascular structure.
10. It has Rhizoids for absorbation and attachment.
11. The formation of sex organ is present on gametophyte.
12. Male sex organ called antheriduim and female sex organ called archegonicem.
13.  Formation of male gametes on antheriduim called antherozoids. (Biflagellated)
14. Formation of female gamete take place in archengonia called egg.
15. Fertilisation takes place by zoidogamy and zygote formed
16. Zygote develops into embryo
17. Now, this embryo develop and forms  saprophytic plant.
18. Sexual reproduction in pteridophyte is monogamous.
19. Life cycle is diplo-haplontic type.
20. Sporophyte & gametophyte are independent from each other.


Pteridophyte is divide into 4 classes

1. Psilopsida
2. Lycopsida
3. Sphenopsida
4. Pteropsida

PSILOPSIDA

• The most ancient vascular plants are placed in this classes having many primitive character .
• Then, plant bodies differentiated into stems (Rhizome), scaly leaves & rhizoids.
• Only one living genus is present in this class Pislotum- A living fossils.
• Rhynia & Horneophyton- fossil plant.