Plant Pathology MCQ Question and Answer | Agriculture MCQ Question

A man supplied excess fertilizer and watered the grass well. After some time the leaves turn brown because osmosis occurs in root and root dies.
Too much fertilizer can burn or desiccate roots, ultimately killing the plant. Too much fertilizer can also be harmful to the environment.
Over-fertilization of commercial pots or lawn plants results in high concentrations of soluble salts in the potting medium. These salts damage roots by slowing the net flow of water into the roots and indirectly by predisposing the plants to certain root diseases and damping off them.

Fungi imperfecti includes Deuteromycotina.
Deuteromycota and fungi imperfecti are anamorphic fungi or mitosporic fungi, but these are terms without taxonomic rank. Examples are Alternaria, Colletotrichum, Trichoderma etc.
Deuteromycotina (imperfect fungi), is a grouping erected to accommodate fungi for which the sexual phase (perfect state) is unknown.
They are known as imperfect fungi because only their asexual and vegetative phases are known. They have an asexual form of reproduction, meaning that these fungi produce their spores asexually, in a process called sporogenesis.

The number 32 in 12-32-16 represents P₂O₅ content.
Fertilizer grade is an expression referring to the legal guarantee of the available plant nutrients expressed as a percentage by weight in a fertilizer.
12-32-16 grade of NPK complex fertilizer indicates the presence of 12% nitrogen (N), 32% phosphorous (P₂O₅) and 16% potash (K₂O).

The vector of citrus greening is Psyllid.
The natural vector of African citrus greening and D. citri is the natural vector of Asian citrus greening, either psyllid vector can transmit both greening agents under experimental conditions.
The Asian citrus psyllid, is the most important pest of citrus worldwide because it serves as a vector of "Candidatus Liberibacter" species (Alphaproteobacteria) that cause huanglongbing (citrus greening disease).

Alcohol is a product of anaerobic respiration.
Anaerobic respiration is respiration using electron acceptors other than molecular oxygen (O₂). Although oxygen is not the final electron acceptor, the process still uses a respiratory electron transport chain.
The end product of anaerobic respiration in plants is ethanol. At the same time, the end product of anaerobic respiration in animals is lactic acid.

The smallest plant pathogenic agent is Viroid.
Viroids are small single-stranded, circular RNAs that are infectious pathogens.
The first discoveries of viroids in the 1970s triggered the historically third major extension of the biosphere to include smaller lifelike entities after the discoveries in 1675 by Antonie van Leeuwenhoek.
viroids are composed of nucleic acid, they do not code for any protein. The viroid's replication mechanism uses RNA polymerase II, a host cell enzyme normally associated with the synthesis of messenger RNA from DNA, which instead catalyzes the "rolling circle" synthesis of new RNA using the viroid's RNA as a template.

Ammonium nitrate contains 33 - 35% N.
Ammonium nitrate is a chemical compound with the chemical formula NH₄NO₃. It is a white crystalline salt consisting of ions of ammonium and nitrate. It is highly soluble in water and hygroscopic as a solid, although it does not form hydrates.
Ammonium nitrate is an important fertilizer with an NPK rating of 34-0-0 (34% nitrogen). Ammonium nitrate's advantage over urea is that it is more stable and does not rapidly lose nitrogen to the atmosphere.

Water-logged soil condition is suitable for denitrification.
Water-logged soil condition is suitable for denitrification. When oxygen is limited as in waterlogged conditions, some bacteria use nitrate to support respiration. Thus, denitrification occurs in anaerobic conditions with the presence of denitrifying microorganisms, soluble C compounds and oxidized forms of N.

The chromosome number in the oosphere is 8. The number in angiospermic endosperm shall be 24. The endosperm is gametophytic tissue and is haploid. A gymnopsermic leaf is a somatic organ that has diploid chromosome number in its cell.
Endosperm is triploid 3n. As, n = 8.
Thus, the number in angiospermic endosperm will be 8 × 3 = 24

The Reoviridae family of viruses includes the viruses that infect humans, insects and plants.
Reoviridae is a family of double-stranded RNA viruses. Member viruses have a wide host range, including vertebrates, invertebrates, plants, protists and fungi.
They lack lipid envelopes and package their segmented genome within multi-layered capsids and are non-enveloped and have an icosahedral capsid composed of an outer (T=13) and inner (T=2) protein shell.
Reovirus infections occur often in humans, but most cases are mild or subclinical. Some viruses of this family, such as phytoreoviruses and oryzaviruses, infect plants.