Plant Pathology MCQ Question and Answer | Agriculture MCQ Question

The C : N ratio of sawdust is 225 : 1.
Organic matter that is deposited in marine sediments contains a key indicator as to its source and the processes it underwent before reaching the floor as well as after deposition, its carbon to nitrogen ratio.
A carbon-to-nitrogen ratio (C/N ratio or C : N ratio) is the ratio of the mass of carbon to the mass of nitrogen in organic residues.
It is other things that, be used in analyzing sediments and soil including soil organic matter and soil amendments such as compost.

The nutrient with a key role in biological N-fixation is Molybdenum.
Nitrogen fixation is a chemical process by which molecular nitrogen (N₂), with a strong triple covalent bond, in the air is converted into ammonia (NH₃) or related nitrogenous compounds.
The conversion of N₂ into ammonia occurs at a metal cluster called FeMoco, an abbreviation for the iron-molybdenum cofactor. Molybdenum-dependent nitrogenase is the most commonly present nitrogenase.

Zn element is not the major nutrient element.
Zinc is a micronutrient for plants, require in less quantity for growth and development.
Zinc participates in chlorophyll formation, and also activates many enzymes. Symptoms of zinc deficiency include chlorosis and stunted growth.

Cyanobacteria photosynthetic bacteria possess both PS I and PS II.
Cyanobacteria are photosynthetic microorganisms that are abundant in nature.
There are two types of photosystems in cyanobacteria, algae, and higher plants, called photosystem I (PSI, plastocyanin-ferredoxin oxidoreductase) and photosystem II (PSII, water-plastoquinone oxidoreductase), both of which are multisubunit membrane complexes.

The most striking symptom of false smut of rice (Claviceps oryzae-sativae) is the Transformation of individual kernels into large, velvety, green balls, Sometimes the size of the kernel is more than twice the diameter of the normal grain, and also the colour of the kernels finally changes to greenish black.
False smut causes chalkiness of grains which leads to a reduction in grain weight. It also reduces seed germination.
Plants infected with false smut have individual rice grains transformed into a mass of spore balls. These spore balls are initially orange and then turn greenish black when these mature.

Margosa is a highly effective product in reducing the root-knot population belonging to Azadirachta indica.
Azadirachta indica, commonly known as neem, nimtree, or Indian lilac, also known as Margosa is a tree in the mahogany family Meliaceae.
Root-knot nematodes are one of the plant-damaging nematodes in agriculture causing a projected annual yield loss of 12% worldwide. These nematodes burrow into the soft tissues of root tips and young roots and cause the nearby root cells to divide and enlarge.
Neem is effective in reducing root-knot nematode population.

The richest source of nitrogen is Dried blood.
A blood meal is a dry, inert powder made from blood, used as a high-nitrogen organic fertilizer and a high-protein animal feed. N = 13.25%, P = 1.0%, K = 0.6%.
It is one of the highest non-synthetic sources of nitrogen. It usually comes from cattle or hogs as a slaughterhouse by-product.

A photosynthetic organism that does not release oxygen is a green sulphur bacterium.
These bacteria are a phylum of obligately anaerobic photoautotrophic bacteria that metabolize sulfur.
Green sulfur bacteria are nonmotile and capable of anoxygenic photosynthesis.
They live in anaerobic aquatic environments. In contrast to plants, green sulfur bacteria mainly use sulfide ions as electron donors. They are autotrophs that utilize the reverse tricarboxylic acid cycle to perform carbon fixation.

a. R. lupine in Lupine group. They can fix nitrogen from the atmosphere into ammonia via a rhizobium root nodule symbiosis, fertilizing the soil for other plants. This adaptation allows lupins to be tolerant of infertile soils and capable of pioneering change in barren and poor-quality soils.
b. R.trifoli in Clover group. Clover or trefoil are common names for plants of the genus Trifolium consisting of about 300 species of flowering plants.
c. R. japonicum and Soybean. Soybean plants to get their necessary dose of nitrogen, partner with bacteria called rhizobium japonicum which can convert atmospheric nitrogen into organic forms the plant can use.
d. R. mcliloti and Alfa alfa. R. mclloti is an aerobic, Gram-negative, and diazotrophic species of bacteria. S. meliloti are motile and possess a cluster of peritrichous flagella. S. meliloti fix atmospheric nitrogen into ammonia for their legume symbionts, such as alfalfa.

Interveinal chlorosis occurs due to a deficiency of Iron.
Interveinal chlorosis, often called iron chlorosis can be caused by a deficiency of several micro-nutrients; Iron, Zinc, and Manganese, all of which the symptoms look similar.
The yellowing of the leaves can be caused by several cultural or environmental issues.