Plant Pathology MCQ Question and Answer | Agriculture MCQ Question

Cell A has O.P. = 10 atm. And T.P. = 5 atm. DPD = O.P. - T.P. = 10 - 5 = 5 atm.
Cell B has O.P. = 15 atm. And T.P. = 12 atm. DPD = 15 - 12 = 3 atm.
The water flow from low to high pressure, as the DPD of cell B, is 3 and the DPD of cell A is 5, therefore water will flow from cell B to A.

The amount by which water potential is reduced due to the presence of solute is called Solute potential.
Solute potential (Ψ_s), also called osmotic potential, is negative in a plant cell and zero in distilled water. Solutes reduce water potential by consuming some of the potential energy available in the water.
Solute potential (Ψ_s) decreases with increasing solute concentration; a decrease in Ψ_s causes a decrease in the total water potential.

Heterodera avenne is Cyst nematode.
Heterodera avenae, the cereal cyst nematode or European cyst nematode, is a plant pathogen and an obligate parasite of cereal crops including barley, oats, wheat and rye.
Cereal crops infected with this nematode are more susceptible to infection by fungal diseases such as rhizoctonia root rot.
The cysts can withstand harsh conditions and can be spread in soil, by agricultural machinery, by animals, by wind, by dust storms or by other means.

The availability of P₂O₅ is maximum at Neutral.
Phosphorus pentoxide is a chemical compound with the molecular formula P₂O₅. This white crystalline solid is the anhydride of phosphoric acid. It is a powerful desiccant and dehydrating agent.
The soil pH for optimum phosphorus availability is 6.5.
At high or neutral pH, phosphate reacts with calcium to form minerals, such as apatite.
At low pH, under acidic conditions, phosphorus may react with aluminum and iron to form minerals, such as strengite and varescite.

'Fungi and Plant Diseases' was written by B. B. Mundakur.
Balchandra Bhavanishankar Mundkur was an Indian mycologist and plant pathologist. He worked at the Indian Agricultural Research Institute and later as a professor of botany at the University of Poona.
He published Fungi and Plant Diseases in 1949 and a monograph on the Ustilaginales of India in 1952 apart from research papers. He was elected Fellow of the Indian National Science Academy in 1946.

Serological tests can't be used for the detection of Viroids.
CDC's serologic test is an enzyme-linked immunosorbent assay (ELISA)-based test to detect SARS-CoV-2 antibodies in serum or plasma components of blood.
Virus antigens are investigated by antigen detection assays. Serological diagnosis is based on either the demonstration of the presence of virus-specific IgM antibodies or a significant increase in the levels of specific IgG antibodies.

All plant viruses (except cauliflower mosaic virus) contain RNA.
Plant viruses are obligate intracellular parasites that do not have the molecular machinery to replicate without a host. The great majority have an RNA genome, which is usually small and single stranded (ss), but some viruses have double-stranded (ds) RNA, ssDNA or dsDNA genomes.
Cauliflower mosaic virus (CaMV) is a member of the genus Caulimovirus, one of the six genera in the family Caulimoviridae, which are pararetroviruses that infect plants. The viral particles contain DNA instead of RNA.

Single super phosphate is a water soluble fertilizer.
Single superphosphate (SSP) was the first commercial mineral fertilizer, and it led to the development of the modern plant nutrient industry. This material was once the most commonly used fertilizer, but other phosphorus (P) fertilizers have largely replaced SSP because of its relatively low P content.
SSP is the only Sulphur providing fertilizer in India which contains water soluble phosphorus easily taken up by plants.

The percentage of radiant energy entering the reaction site in photosynthesis which is converted into potential energy is 35%.
During photosynthesis, “producers” like green plants, algae and some bacteria convert light energy from the sun into chemical energy.
Radiant energy is the physical energy resulting from electromagnetic radiation, usually observed as it radiates from a source into the surrounding environment. Radiant energy sources include the entire electromagnetic radiation spectrum, including gamma rays, x-rays, radio frequencies, microwaves, sunlight and heat.

The most suitable form of N for flooded rice soil is Ammonium.
Rice plant depends mainly on its nitrogen upon the decomposition of organic matter under anaerobic conditions and in the early stages of growth takes up nitrogen in the form of ammonia which is the stable form of nitrogen in submerged soils.
The main form of nitrogen (N) taken up by rice roots is shifted from ammonium (NH₄) in flooded paddy soil to nitrate in upland soil.