Plant Pathology MCQ Question and Answer | Agriculture MCQ Question

A. C₃ plants include some of the most important sources of calories all over the world: cowpea, cassava, soybean and rice. Grasses, such as maize, sorghum and sugarcane, are widely cultivated in modern agriculture are C₄ plants.
B. Calvin cycle ⟶ PGA. Phosphoglyceric acid, PGA is the conjugate acid of 3-phosphoglycerate or glycerate 3-phosphate. This glycerate is a biochemically significant metabolic intermediate in both glycolysis and the Calvin-Benson cycle.
C. Hatch and Slack cycle ⟶ OAA. The Hatch and Slack pathways are also known as the C₄ pathway because the first stable product of this pathway is 4-C carbon compound OAA (Oxaloacetate ).
D. C₄ - Kranz anatomy. The C₄ biochemical pathway relies on a specific suite of leaf functional properties, often referred to as Kranz anatomy.

For the effective control of wilt, Pigeon pea should be intercropped with Sorghum.
Fusarium wilt of pigeon pea is both a soil-borne and seed-borne disease in which the infection level of untreated seeds may range from 13% to 19%. The infected seeds thus serve as a primary vehicle for the spread of this disease over long distances or to newer areas.
Sorghum as an intercrop has been found to reduce wilt (Fusarium udum) incidence in pigeon pea by about 30 percent.

The maximum fixation of K occurs in 2 : 1 type clay minerals.
The major minerals responsible for K fixation are illite, vermiculite and smectite. It has been demonstrated that vermiculite and smectite minerals have more ability to fix K compared to other 2 : 1 minerals due to the higher specific surface area and negative layered charge.

Red drop discovered by Emerson is due to disruption of photochemical activity of PS II.
The Emerson effect is the increase in the rate of photosynthesis after chloroplasts are exposed to the light of wavelength 680 nm (deep red spectrum) and more than 680 nm (far red spectrum).
When simultaneously exposed to light of both wavelengths, the rate of photosynthesis is far higher than the sum of the red light and far red light photosynthesis rates.
The effect was early evidence that two photosystems, processing different wavelengths, cooperate in photosynthesis.

The Karnal bunt of wheat is caused by Neovossia indica.
Karnal bunt of wheat, caused by Neovossia indica (Mitra) Mundkur, was first reported in 1931 from Northwestern India in experimental plantings, It is a disease of wheat and triticale. The fungus and the plant disease that it causes are harmless to humans and animals.
It reduces grain quality through the production of masses of powdery spores that discolour the grain and grain products.

The cell wall lacks microorganism MLO.
Mycoplasmas (MLO) are fastidious bacteria that lack a cell wall. They belong to the class Mollicutes and are the smallest known free-living organisms.
Many require sterols for growth, and Ureaplasma species require urea for fermentation. Mycoplasmas measure only 0.3 to 0.8 µm in size.

Fumarase changes fumaric acid into Malic acid.
Living cells make an enzyme called fumarase. It converts a chemical called fumaric acid into L-malic acid.
This is a crucial step in primary metabolism and aerobic respiration, the process of using oxygen to release energy for life.

Kranz's anatomy is typical of C₄ plants.
C₄ plants often possess a characteristic leaf anatomy called kranz anatomy, from the German word for the wreath. Their vascular bundles are surrounded by two rings of cells; the inner ring, called bundle sheath cells, contains starch-rich chloroplasts lacking grana, which differ from those in mesophyll cells present as the outer ring.
The primary function of Kranz anatomy is to provide a site in which CO₂ can be concentrated around RuBisCO, thereby avoiding photorespiration.

The citric acid cycle is the alternate name of the TCA cycle.
The citric acid cycle (CAC) also known as the Krebs cycle or the TCA cycle (tricarboxylic acid cycle) is a series of chemical reactions to release stored energy through the oxidation of acetyl-CoA derived from carbohydrates, fats, and proteins.
The Krebs cycle is used by organisms that respire to generate energy, either by anaerobic respiration or aerobic respiration.

The most conspicuous chemical change that takes place when soil is flooded is the reduction of Fe.
Flooded soils are a condition in which an area of soil is oversaturated with water, often due to natural occurrences or with the intended purpose of agricultural reasons like the cultivation of rice.
The most conspicuous chemical change that takes place in the flooded soil is the reduction of iron (Fe).
Competition generally limits the use of weaker electron acceptors, iron reducers may exist in the soil but will be dominated by the presence of denitrifiers, who will grow faster with access to their stronger electron acceptor.