Plant Pathology MCQ Question and Answer | Agriculture MCQ Question

In the two light reactions of photosynthesis PS I produces the strong reductant NADPH while PS II is a strong oxidant.
Photosystem I is an integral membrane protein complex that uses light energy to catalyze the transfer of electrons across the thylakoid membrane from plastocyanin to ferredoxin. The enzyme transfers the electron from reduced ferredoxin to NADP⁺ to complete the reduction to NADPH in PS I.
Photosystem II provides the electrons for all of photosynthesis to occur. The hydrogen ions (protons) generated by the oxidation of water help to create a proton gradient that is used by ATP synthase to generate ATP.

Plants growing in urea sprayed but Mg deficient soil will show yellowing of leaves.
Magnesium is the central core of the chlorophyll molecule in plant tissue. Thus, if Mg is deficient, the shortage of chlorophyll results in poor and stunted plant growth along with yellowing of leaves. Magnesium also helps to activate specific enzyme systems.
A plant growing in magnesium-deficient soil would show chlorosis inspite of being sprayed with urea (nitrogen).

K. C. Mehta has done most of his work on rust diseases in India.
The annual recurrence of stem rust of wheat in North Indian plains was discovered by Prof. K. C. Mehta. Since the 1950s, wheat strains bred to be resistant to stem rust have become available.
He worked on the recurrence of wheat rusts in the plainlands of India. He found that though the rust spores were killed by the summer heat, new spores were blown in from the hills causing fresh infections every year.

Loose smut is controlled by Seed treatment.
Since loose smut fungus depends on seed for its survival and carries over from one season to another, growing disease free seed is the only alternative method of control available at present for large scale adoption. Treat the seed with Vitavax at the rate of 2.5 g per kg of seed before planting.
Solar heat treatment of infected seed is highly valuable in the hot summer areas of the plains to make seed disease free. On a bright sunny day in the last week of May or first week of June. Soak the seed in water for about four hours in the morning and then dry it under hot sun in the afternoon. Store the well dried seed for use in next wheat season. The seed soaking activates the dormant fungus in the seed and heat of the sun kills it.

The importance of respiration in plants is it liberates energy.
Cellular respiration is a process that occurs in the mitochondria of all organisms. In this process, both plants and animals break down simple sugars into carbon dioxide and water and release energy in the form of adenosine triphosphate (ATP).

Inorganic nutrients are present in the soil as electrically charged ions.
Inorganic nutrients, such as nitrogen and phosphorus, are important in the distribution and the abundance of living things. Plants obtain these inorganic nutrients from the soil when water moves into the plant through the roots.
e.g : Plants can take up two forms of nitrogen, nitrate (NO₃^-) and ammonium (NH₄^-).

Sugar and vinegar, Salt and sugar and Vinegar can preserve food stuff.
Vinegar may be used to pickle food, a preservation method that extends the shelf life of perishable foods by killing bacteria. Pickling involves soaking a food in a brine solution made from vinegar, water, salt, and sugar, which also changes the food's flavor.
Use of salt and sugar curing to prevent microbial growth. Sugar as a preservative by acting as a humectant (maintaining and stabilising the water content in foods) sugar helps to prevent or slow the growth of bacteria, moulds and yeast in food like jam and preserves.

Green plant do not give out CO₂ during day time because they consume it in photosynthesis.
During daylight hours, plants take in carbon dioxide and release oxygen through photosynthesis, and at night only about half that carbon is then released through respiration. Plants typically absorb CO₂ and release oxygen, but they also “exhale” CO₂, particularly at night, when photosynthesis ceases due to the lack of sunlight.

Sigmoid curve is depicted by Polycyclic.

Movement of pollen tube towards embryo sac is Chemotactic.
Chemotaxis is a fundamental biological process in which a cell migrates following the direction of a spatial cue. This spatial cue is provided in a form of a gradient of chemoattractants. Chemotactic movement causes the pollen grains to reach the embryo sac and results in fusion, which is also called syngamy.
The pollen tube arrives in the micropyle of the integument of the ovule, and enters the embryo sac. The synergids of the embryo sac literally put their energies together to burst the end of the pollen tube.