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Farmers in a particular region were concerned that pre-mature yellowing of leaves of a pulse crop might cause decrease in the yield. Which treatment could be most beneficial to obtain maximum seed yield ?
A
Frequent irrigation of the crop
B
Treatment of the plants with cytokinins along with a small dose of nitrogenous fertilizer
C
Removal of all yellow leaves and spraying the remaining green leaves with 2,4,5-trichlorophenoxy acetic acid
D
Application of iron and magnesium to promote synthesis of chlorophyll
Detailed Solution
Premature yellowing of leaves is chlorosis, i.e. the loss or non-formation of chlorophyll.
Magnesium is a constituent of the chlorophyll molecule, and iron is essential for the formation of chlorophyll (it activates the enzymes of chlorophyll synthesis).
Deficiency of either element causes chlorosis, which lowers photosynthesis and hence the seed yield.
Applying iron and magnesium promotes the synthesis of chlorophyll, keeps the leaves green and photosynthetically active, and so gives the maximum seed yield.
A pulse crop fixes its own nitrogen through root nodules, so nitrogenous fertiliser is not the main need.
Frequent irrigation does not correct chlorosis, and 2,4,5-T is a herbicide (defoliant) that would damage the crop.
So the most beneficial treatment, as given in the answer key, is the application of iron and magnesium to promote synthesis of chlorophyll.
Magnesium is a constituent of the chlorophyll molecule, and iron is essential for the formation of chlorophyll (it activates the enzymes of chlorophyll synthesis).
Deficiency of either element causes chlorosis, which lowers photosynthesis and hence the seed yield.
Applying iron and magnesium promotes the synthesis of chlorophyll, keeps the leaves green and photosynthetically active, and so gives the maximum seed yield.
A pulse crop fixes its own nitrogen through root nodules, so nitrogenous fertiliser is not the main need.
Frequent irrigation does not correct chlorosis, and 2,4,5-T is a herbicide (defoliant) that would damage the crop.
So the most beneficial treatment, as given in the answer key, is the application of iron and magnesium to promote synthesis of chlorophyll.