Plant Pathology - Study Mode
[#801] Three carbons of phosphoglyceric acid formed during carbon fixation are derived from
Correct Answer
(D) RuBP + CO 2
Explanation
Solution: Three carbons of phosphoglyceric acid formed during carbon fixation are derived
from RuBP + CO 2 . Phosphoglyceric acid (PGA), a 3-carbon organic acid formed during glycolysis is the first relatively stable compound formed in the Calvin cycle after the fixation of carbon dioxide in C 3 plants. The first product, an unstable 6-carbon compound, is formed when carbon dioxide combines with ribulose diphosphate.
[#802] Damping off and leaf blights are very effectively checked by
Correct Answer
(D) Copper oxychloride
Explanation
Solution: Damping off and leaf blights are very effectively checked by Copper oxychloride. Damping off is a horticultural disease or condition, caused by several different pathogens that kill or weaken seeds or seedlings before or after they germinate. It is most prevalent in wet and cool conditions. Leaf blight disease is caused by fungus. The disease develops on leaves, on sorghum particularly under humid conditions by producing reddish-purple or tan spots that coalesce to form large lesions. Spraying or drenching the soil with a recommended anti-fungal treatment, such as copper oxychloride helps suppress the disease.
[#803] Chestnut compound was first used for
Correct Answer
(C) Damping off
Explanation
Solution: Chestnut compound was first used for Damping off. Chestnut compound was first suggested by Bewley in 1922 and is used especially to control damping-off diseases of seedlings. The Chestnut compound contains two parts of copper sulphate and 11 parts of ammonium carbonate. The two substances are well powdered and thoroughly mixed and the dry mixture is stored in an airtight receptacle for 24 hours before being used.
[#804] Haploid plant cultures are produced from
Correct Answer
(C) Pollen grain
Explanation
Solution: Haploid plant cultures are produced from Pollen grains. Haploid culture is an in vitro technique used to produce haploid (cells have half the number of chromosomes) plants. Blackslee in 1922 first reported the natural occurrence of the haploid condition in Datura plants, due to parthenogenesis. Haploid plants can be produced through in vitro culture of male gametophytic cells at the microspore or immature pollen developmental stage.
[#805] Which of the following nutrients is available at neutral pH value?
Correct Answer
(D) P
Explanation
Solution: Phosphorus is a nutrient that is available at a neutral pH value. Precipitation of phosphorus as slightly soluble calcium phosphates occurs in calcareous soils with pH values around 8.0. Under acid conditions, phosphorus is precipitated as Fe or Al phosphates of low solubility. Maximum availability of phosphorus generally occurs in a pH range of 6.0 to 7.0.