3. Thallus
Mycellium superficial, septate, branched.
Hyaline septate, uninucleate hyphae.
Grows over surface of host.
Forms appressorium with small lobe.
It penetrates the epidermis of host and develop haustorium .
It has elongated neck with swollen uninucleate body.
Body bears finger like projection at both ends & lies in vacuole region of
host cell.
It is ecto-obligate parasite.
6. Contd:
Takes place by conidia.
Somatic hyphae produce Conidiophores.
Conidiophores are short, straight, and swollen at the base.
Conidia in Basipetal succession.
Mature conidia are hyaline, one celled,uninucleate, oval .
They contain vacuoles, lipid granules, water.
Conidia disseminate by wind, germinate producing one or two germ tubes.
Spread hyphae on host.
8. •
.
.
Sexual organs are constricted from the erect branch-tips of two adjacent but distinct
hyphae.
The ascogonium is large, ovoid in shape.
The antheridium is smaller and more slender
Each contains one nucleus only.
at their point of contact, a passage is developed by the dissolution of walls.
The antheridial nucleus passes through this passage into the ascogonium
Plasmogamy takes place which is followed by the development of ascogenous hyphae
Asci and ascospores are developed within the cleistothecium.
9. Cleistothecium
The ascogonium develops to a multinucleate tube-like structure which
divides simultaneously into several cells, the sub terminal one of which is
binucleate .
This binucleate cell gives rise to one to several ascogenous hyphae, the
cells of which give rise to asci. Karyogamy and the development of
ascospores take place in a process
Sterile branches have arisen from the base of the ascogonium surrounding
it, closely intertwining to form the cleistothecial peridium.
The outer surface of the peridium eventually becomes dark-brown, and
develops long filamentous mycelioid appendages.
10. Contd:
The inner layer of tissue forms a source
of food for the asci which are developing
in the cleistothecium.
The cleistothecium bears more than one
asci, in each of which 8 ascospores
The asci and ascospores are liberated
out by the rupture of the
cleistothecial wall .
