Q.30. Draw the labelled diagram of T.S. of the Hypertrophied mustard plant. (2014)
Ans.
Q.31. Mention the systematic position of the fungal genera of your syllabus. (2014)
Ans. Lower Fungi: -
Albugo, Phytophthora, Mucor
Albugo: -
Systematic position -
Division - Mycota
Sub-division - Eumycotina
Class - Oomycetes
Order - Peronosporales
Family - Albuginaceae
Genus - Albugo or Cystopus
Phytophthora: -
Systematic Position - Go through previous question
Mucor: -
Systematic Position - Go through Q.21(a).
Higher Fungi: - Ascomycetes: Saccharomyces, Sphaerotheca, Peziza
Basidiomyccetes: Ustilago, Puccinia, Agaricus.
Saccharomyces: -
Systematic Position -
Division - Mycota
Sub-division - Eumycotina
Class - Ascomycetes
Sub-class - Hemiascomycetidae
Order - Endomycetales
Family - Saccharomycetaceae
Genus - Saccharomyces (The most important and throughly investigated genus of all the yeast)
Sphaerotheca: -
Systematic Position -
Division - Mycota
Sub-division - Eumycotina
Class - Ascomycetes
Sub-Class - Euascomycetidae
Series - Pyrenomycetes
Order - Erysiphales
Family - Erysiphaceae
Genus - Sphaerotheca
Peziza: -
Systematic Position -
Division - Mycota
Sub division - Eumycotina
Class - Ascomycetes
Sub-class - Euascomycetidae
Series - Discomycetes
Order - Pezizales
Family - Pezizaceae
Genus - Peziza
Ustilago: -
Systematic Position -
Division - Mycota
Sub-division - Eumycotina
Class - Basidiomycetes
Sub-Class - Heterobasidiomycetidae
Order - Ustilaginales
Family - Ustilaginaceae
Genus - Ustilago
Puccinia: - Go through Q.21(c).
Agaricus: -
Systematic Position -
Division - Mycota
Sub-division - Eumycotina
Class - Basidiomycetes
Sub-class - Homobasidiomycetidae
Order - Agaricales
Family - Agaricaceae
Genus - Agaricus
Fungi Imperfecti: - Cerospora, ASpergillus
Cerospora: -
Systemic Position -
Division - Mycota
Sub-division - Eumycotina
Form-class - Deuteromycetes
Form-order - Moniliales
Form-family - Dematiaceae
Form-genus - Cercospora
Aspergillus: -
Systemic Position - Go through Q.21.
Q.32. Differentiate between Hypertrophe and Hyperplasia. (2016)
Ans. Hypertrophy and Hyperplasia: -
Hypertrophy (overgrowths) is an abnormal increase in size of one or more organs of a plant in response to the attack of a pathogen. It results in abnormal growth causing distortions, swelling, leaf curl and galls. The excessive growth may be due to two processes, hyperplasia and hypertrophy. The former consists in rapid cell division and thus increase in the number of cells of which the organs is composed. Hypertrophy leads to abnormal increase in size of cells only. The attack of corn smut stimulates abnormal and rapid cell division (hyperplasia) and enlargment of individual cells (hypertrophy) of the infected organs resulting in the formation of overgrowths called the corn galls or tumours. Witches broom is another result of hypertrophy. It is a compact duster of fine slender benches generally developing from an enlarged axis and the whole looking like a broom. The hypertrophied parts becomes inedible.
Q.33. Write short note on Caenocytic Hyphae. (2013)
Ans. Caenocytic Hyphae: - Each hyphae consists of an outer thin wall and a cavity lined or filled with the protoplasm. In some ture fungi, the protoplasm of the hyphae is continous, but in others the hyphae are divided by few or many partitions or cross-walls called septa (sing. septum), into cells. The true fungi whose hyphae have no septa are called aseptate, as in phycomycetes (fig. A, B) and those with septa are called septate as in Ascomycete, Basidiomycetes and Deuteromycetes (Fungi imperfecti).
In case of aseptate hyphae, a number of nuclei are embedded in the cytoplasm and are scattered more or less uniformly throughout its mass, and this type of vegetative body is called coenocytic.
Fig: - Vegetative hyphae and fungal tissuse. A - aseptate mycelium. B - protion of an aseptate hyphae. C - septate mycelium. D - protion of a septate hyphae. E to F-fungal tissues (plectenchyma). E - pseudoparenchyma, and F prosenchyma.
Q.34. Mention the systematic position of Cercospora giving suitable reasons. (2016)
Ans. Systematic position
Division - Mycota
Sub-division - Eumycotina
Form-class - Deuteromycetes
Form-order - Moniliales
Form-family - Dematiaceae
Form-genus - Cercospora
Suitable reasons: -
Go through Q.19.
Q.35. Draw the labelled diagram of the T.S. of stem, of wheat showing rust infection. (2015)
Ans.
Q.36. Differentiate between Uredospore and Teleutospere. (2016)
Ans. Uredospores: -
In plains of India wheat is sown in October or November, but the infection becomes evident only in the month of February or March, when vertically elongate reddish brown pustules appear mostly on the stem or leaf. These pustules in reality are Uredosori containing uredospores. Uredosori develop from branched and separate mycelium which is divided into several multicellular hyphae. Each cell of hyphae is divided into several multicellular hyphae arrange themselves in clusters, each hypha is called as sporophore. These are situated below the epidermis the apical cell of sporophore enlarges and divides into an upper spore initial and lower basal cell. The basal cell form stalk on elongation while spore cell form uredospores. Each spore is surrounded by an outer brownish wall expospore and the inner delicate endospore. It consists of two nuclei and cytoplasm also. On maturation of uredospores the epidermis of host brusts and they are liberated in air. Uredospores after dissemination, germinate in favourable conditions and form germ tubes which infect other healthy wheat plants. Thus rust disease get spread up through uredospores in the entire field of wheat.
Teleutospores: -
Later in the season, in April in the plains of Northern India, when the wheat grains are maturing, the uredia begin to produce a few teleutospores. As the season advances more and more teleutospores are formed. A pustule producing teleutospore is called as teleutospores or telium outwardly these appear as elongated black coloured streaks on the stem leaf of wheat plants. The stage is called black stage or teleutospore stage of rust. Like uredospore also develop from multicellular hyphae possessing dikaryotic cells. The teleutospore is bicelled and spindle shaped. It is covered by exospores and endospore. The dikaryotic nuclei fuse together in the teleutospore and form a diploid nucleus.
The teleutospore resist in unfavourable conditions. On maturation the teleutospores are shut out by the rupture of epidermis and are carried to long distance by wind.
Q.37. Differentiate between white rust and black rust. (2016)
Ans. 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.