STRUCTURAL ORGANISTION OF PLANTS AND ANIMALS
ANATOMY OF FLOWERING PLANTS
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Youngest secondary phloem is just outside the cambium while youngest secondary xylem inside the cambium
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Oldest secondary phloem is just inside the primary phloem while oldest secondary xylem is just above pith
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Secondary medullary ray passes through both secondary xylem and secondary phloem
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All
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Detailed explanation-1: -Secondary growth results in increase in girth or diameter of the stem by formation of secondary tissue by the activity of lateral meristem. So for study of secondary growth, teak (angiosperm) and pine (gymnosperm) are best suited. In wheat, fern and sugarcane there is no secondary growth. So, option C is correct.
Detailed explanation-2: -Secondary growth occurs in many roots and usually results in the thickening of the root diameter by the addition of vascular tissue. Initiation of secondary growth occurs when cells in the residual procambium and parts of the pericyle begin to make periclinal divisions.
Detailed explanation-3: -All the statements are correct regarding secondary growth in dicot stems. The vascular cambial ring develops as a circular ring since beginning. The vascular cambial ring is completed by both the primary (intrafascicular) strip and secondary (interfascicular) strip.
Detailed explanation-4: -Solution : Secondary growth usually does not occur in monocotyledons.
Detailed explanation-5: -So, the correct option is ‘Secondary xylem is cut off more in quantity towards outer side’