Plant Pathology - Study Mode
[#256] The source of oxygen evolved during photosynthesis is
Correct Answer
(B) H 2 O
Explanation
Solution: The source of oxygen that evolved during photosynthesis is H 2 O. 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.
[#257] Pollenkitt is formed from
Correct Answer
(D) Tapetum
Explanation
Solution: 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.
[#258] Which form of nitrogenlous fertiliser will be preferred for paddy and potato?
Correct Answer
(B) Ammonical
Explanation
Solution: An ammonical form of nitrogenous fertilizer will be preferred for paddy and potatoes. Ammonium sulphate [(NH 4 ) 2 SO 4 ]: 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.
[#259] Brown leaf spot disease of rice is caused by
Correct Answer
(A) Drechslera oryzae
Explanation
Solution: 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.
[#260] Leaf curl of tomato is spread by
Correct Answer
(B) White fly
Explanation
Solution: 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.