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Phloem of angiosperm is different from that of pteridophytes and gymnosperms in
Phloem of angiosperm is different from that of pteridophytes and gymnosperms in
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Solution
The correct option is C Presence of companion cells
Angiospermic phloem is a composed of four elements namely, sieve elements, companion cell, phloem fibres and phloem parenchyma. The pteridophytes and gymnopserms have sieve cells and phloem parenchyma only; however few gymnosperms have phloem fibres also. Thus, angiosperms have companion cells which are absent in pteridophytes and gymnosperms.
Companion cells are structurally and functionally associated with sieve tube elements which are not present in pteridophytes and gymnosperms; thus no companion cells. Enzymes are not present in phloem. Function of phloem is to food conduction through pressure flow mechanism, not endocytosis which is defined as active import of molecules by cells.
Thus, the correct answer is option C.
Angiospermic phloem is a composed of four elements namely, sieve elements, companion cell, phloem fibres and phloem parenchyma. The pteridophytes and gymnopserms have sieve cells and phloem parenchyma only; however few gymnosperms have phloem fibres also. Thus, angiosperms have companion cells which are absent in pteridophytes and gymnosperms.
Companion cells are structurally and functionally associated with sieve tube elements which are not present in pteridophytes and gymnosperms; thus no companion cells. Enzymes are not present in phloem. Function of phloem is to food conduction through pressure flow mechanism, not endocytosis which is defined as active import of molecules by cells.
Thus, the correct answer is option C.
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