Q.4. Only draw neat and labelled diagram of V.S. of braberry leaf (showing acial stage) infected by Puccinia graminis. (2009,11)
Ans.
Q.5. Write short notes on difference between Rusts and Smuts. (2004)
Ans. Difference between Rusts and smuts
Q.6. Write some similarties between Smuts and Rusts.
Ans. The smuts resemble rusts in the following:
(1) Both monokaryotic and dikaryotic mycelia are observed in their life cycles.
(2) The dikaryotic mycelium constitutes the important part the life cycle. In both the cases, it is perenial and produces teleutospores.
(3) There is no motile stage in their life cycles.
(4) In both smuts and rusts, the teleutospores stage is the resting stage which on germination produces the basidiospores.
(5) No tertiary mycelium and basidioscarps are found.
Q.7. Differentiate primary and alternative host. (2005)
Ans. In the life - cycle of fungus Puccinia graminis tritici two types of hosts are found. Its primary host is wheat (Triticum aestivum) on which it forms main stage of its life - cycle. These stages are uredo stage and Telio - stage, respectively. With the help of this host pathogen moving its life - cycle continue.
Secondary or alternative host of this fungus is Barberry plant on which it reproduce sexually and form its pycnidial and Aecidial stages of its life - cycle. Aecidiospore is developed from Aecidia which again infects the wheat plants. Thus, Barberry plant is called as secondary host of this fungus because in the absence of wheat crop this fungus passes its life on this new host plant.
Q.8. Differentiate the following:
1. White rust and black rust
2. Autoecious and heterocious rust.
3. Parasites and saprophytes. (2006)
Ans. 1. White Rust and Black Rust
(1) White Rust:-
These parasites are member of family Albouginaecae. These are Albugo and Cystopus. They infect plants mainly members of family cruciferae as they attack on Brassica Raphamus cabbage etc. Except root they attack all the part of plant. It appears in pustules which are light yellow in colour. In virulent stage it shows hypertrophy.
Black Rust :-
Pucciniaceae is the most common family of Black rust and Puccinia is the main parasite of this family. It appears on cereals mainly on wheat plant and it is called black stem rust of wheat.
Except root it appears on all the aerial part of plant. Its spots looks like rustly coloured powdery spots on plant parts. After sometime these spots becomes black and long in size found on stems. These long spots are called teleutosorous. These are binucleate and long pointed in structure.
2. Autoecious asnd Heteroecious Rusts: -
Autoecious rusts:-
When rust parasite passes complete its life cycle on single host and all stages of cycle as uredospores teleutospores, basidiospores and pynidiospores are found on single host, the condition is called autoecious, e.g., - Rust of linseed.
Heteroecious rusts:-
When a rust parasite passes some stages of its life - cycle in one host and remaining stages on other host this condition is called heteroecious, e.g. - Puccinia graminis passes some stages on wheat and some on barberry plant.
3. Parasites and Saprophytes:-
parasite-When an organisms obtain food from living host these are called parasite.
They can be obligate or facultative parasite. Obligate parasite take food from living host and facultative parasite take food from living or dead, host e.g., Rust , Smut.
Saprophyte:-
Those organisms absorb their food from dead organic matter are called saprophytes. They may be obligate and facultative, e.g. -Agaricus.