Plant Pathology - Study Mode
[#821] Plasmodiophora brassicae causes the club root disease of crucifers can be controlled by
Correct Answer
(A) Raising pH of soil
Explanation
Solution: Plasmodiophora brassicae causes the club root disease of crucifers can be controlled by Raising the pH of the soil. Clubroot is a fungal disease that affects several plants in the cabbage family including cabbages, radish, mustard and ornamentals such as candytuft. It is caused by the fungus Plasmodiophora brassicae and gets its name from the club-like roots it induces in infected plants. Clubroot thrives in acidic soil, so raising the pH to at least 7.2 may be one of the most effective means of attaining clubroot control.
[#822] In the attack of which class of nematodes, presence of white to brown cysts projecting on the root surface is a characteristic symptom
Correct Answer
(B) Globodera
Explanation
Solution: In the attack of Globodera class of nematodes, the presence of white to brown cysts projecting on the root surface is a characteristic symptom. Globodera is a species of nematode in the family of Heteroderidae. It is well known as a plant pathogen, especially in potatoes and tomatoes. the egg containing white cysts (pallida) or golden cysts (rostochiensis) can be found on the roots of potato plants.
[#823] Which of the following elements is immobile?
Correct Answer
(A) Ca
Explanation
Solution: Calcium is an immobile element among the given options. The calcium ions do not move by mass flow but by a series of exchange reactions along negatively charged sites on the walls of the xylem vessels. Movement can be promoted by the presence of divalent cations and by the chelation of the calcium ion. There is considerable lateral leakage of calcium from the xylem.
[#824] In north India and central India, the black rust inoculum cause from
Correct Answer
(A) South
Explanation
Solution: In north India and central India, the black rust inoculum is caused from the South. Stem rust, also known as cereal rust, black rust, red rust, or red dust, is caused by the fungus Puccinia graminis, which causes significant disease in cereal crops. Crop species that are affected by the disease include bread wheat, durum wheat, barley and triticale. The annual recurrence of stem rust of wheat in North Indian plains was discovered by Prof. K. C. Mehta. The long-distance dissemination of stem rust from the southern foci to central India is reported to be associated with cyclonic rains .
[#825] Tetrad of megaspores is generally
Correct Answer
(B) Linear
Explanation
Solution: Tetrad of megaspores is generally Linear. Megaspores, also called macrospores, are a type of spore that is present in heterosporous plants. The megaspore, or large spore, germinates into a female gametophyte, which produces egg cells. These are fertilized by sperm produced by the male gametophyte developing from the microspore. During megasporogenesis, a diploid precursor cell, the megasporocyte or megaspore mother cell, undergoes meiosis to produce initially four haploid cells (the megaspores). The linear tetrasporic pattern is characterized by cell plates failing to form after either meiosis 1 or 2, and results in one four-nucleate megaspore.