Plant Pathology MCQ Question and Answer | Agriculture MCQ Question

Late blight of potato turned into an epidemic in the year 1845.
Phytophthora infestans is an oomycete or water mold, a fungus-like microorganism that causes the serious potato and tomato disease known as late blight or potato blight.
The Irish Potato Famine, also known as the Great Hunger, began in 1845 when a mold known as Phytophthora infestans (or P. infestans) caused a destructive plant disease that spread rapidly throughout Ireland.

The path of the dark reaction of photosynthesis was traced through the use of ¹⁴CO₂.
Calvin and his co-workers by using the isotope of C which is 14C to trace the path of the carbon fixation in light reaction. Due to his discovery, the cycle is known as the Calvin cycle (Dark reaction) which is the common path for all plants in photosynthesis.

CO₂ is one product in respiration and a reagent in photosynthesis.
Cellular respiration converts ingested nutrients in the form of glucose (C₆H₁₂O₆) and oxygen to energy in the form of adenosine triphosphate (ATP). CO₂ is produced as a byproduct of this reaction.
During photosynthesis, plants take in carbon dioxide (CO₂) and water (H₂O) from the air and soil. Within the plant cell, the water is oxidized, meaning it loses electrons, while the carbon dioxide is reduced, meaning it gains electrons.

A photosynthesizing plant is releasing ¹⁸O more than normal. The plant must have been supplied with H₂O with ¹⁸O.
Ruben, Hassid and Kamen (1941) using a heavy isotope of oxygen, `<sup>18</sup>O` in water, found that oxygen evolved in photosynthesis comes from water evolution of oxygen does not require carbon dioxide.

Infection of smut of maize (Ustilago maydis) occurs during the Vegetative stage.
Corn smut is a plant disease caused by the pathogenic fungus Ustilago maydis that causes smut on maize and teosinte. The fungus forms galls on all above-ground parts of corn species.
The fungus infects all parts of the host plant by invading the ovaries of its host. The infection causes the corn kernels to swell up into tumor-like galls, whose tissues, texture, and developmental patterns are vegetative and mushroom-like.

The source of oxygen that evolved during photosynthesis is H₂O.
Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy, through cellular respiration.
Two water molecules are oxidized by the energy of four successive charge-separation reactions of photosystem II to yield a molecule of diatomic oxygen and four hydrogen ions. The oxidation of water is catalyzed in photosystem II by a redox-active structure.

Pollenkitt is formed from Tapetum.
Tapetum is the innermost cell layer in the anther, which surrounds the developing pollen mother cells (PMCs) and/or microspores supplying nutrition and enzymes required for microsporogenesis and pollen maturation.
Pollenkitt is a covering of yellow sticky substance which is present around the pollen grain. It is formed from tapetum.

An ammonical form of nitrogenous fertilizer will be preferred for paddy and potatoes.
Ammonium sulphate [(NH₄)₂SO₄]: This is a nitrogenous fertilizer that is used for raising the production level of crops like paddy, potato, etc.
In this fertilizer, there is nearly 25% ammonia which is transformed into nitrate by the denitrifying bacteria present in the alkaline soil.

Brown leaf spot disease of rice is caused by Drechslera oryzae.
Drechslera oryzae causes brown leaf spot disease in rice (Oryza sativa L.). This fungal pathogen produces a series of ophiobolins that cause some of the characteristic symptoms of the disease when applied to rice leaves at 10^-4 and 10^-5 M.

The leaf curl of the tomato is spread by Whiteflies.
Tomato yellow leaf curl virus (TYLCV) is the name given to a complex of geminiviruses infecting tomato cultures worldwide. TYLCV is transmitted by a single insect species, the whitefly Bemisia tabaci.
Over a long distance, the virus is primarily spread through the movement of infected plants, especially tomato transplants.