Mineral Nutrition Question 29
29. The plants grown in magnesium-deficient but urea sprayed soil would show
[2000]
(a) deep green foliage
(b) early flowering
(c) yellowing of leaves
(d) loss of pigments in petals
Show Answer
Answer : c
Hints & Solution
(c) Deficiency of magnesium produces chlorosis due to breakdown of chlorophyll. Chlorosis is a condition in which plant foliage produces insufficient chlorophyll. When this happens, leaves do not have their normal green colour; they may be pale green, yellow, or yellow-white. The affected plant has little or no ability to manufacture carbohydrates and may die unless the cause of its chlorophyll insufficiency is treated. Specific nutrient deficiencies (often aggravated by high $pH$ ) cause chlorosis, which may be corrected by supplemental feedings of iron, magnesium or nitrogen compounds in various combinations. Some pesticides, particularly herbicides, may also cause chlorosis, both to target weeds and occasionally to the crop being treated.
