
Do Gymnosperms lack companion cells?
Answer
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Hint: The companion cells are a specialized group of cells present inside the phloem tissues of the angiosperms. These cells are living, nucleated and contain several ribosomes, plastid and mitochondria. Their nuclei are generally large in size.
Complete answer:
The phloem is a type of vascular tissue that carries out the translocation of photosynthetic food. The phloem is composed mainly of : (1) sieve element, (2) companion cell, (3) phloem sclerenchyma, (4) phloem parenchyma.
These cells are present only in angiosperms.
Companion cells contain abundant plasma and nucleus present in angiosperms. These cells are absent in gymnosperms. Gymnosperms do not need root pressure to get water from soil as they are mainly grown in cold and dry climates. Thus gymnosperms lack companion cells.
The companion cells are vertically elongated in structure and angular in cross section.
Note:
Companion cells are present only in angiosperms. Pteridophytes and gymnosperms do not have companion cells but some of them have some cells with similar functions (called albuminous cells). However there is no relationship between sieve cells and albuminous cells.
Complete answer:
The phloem is a type of vascular tissue that carries out the translocation of photosynthetic food. The phloem is composed mainly of : (1) sieve element, (2) companion cell, (3) phloem sclerenchyma, (4) phloem parenchyma.
These cells are present only in angiosperms.
Companion cells contain abundant plasma and nucleus present in angiosperms. These cells are absent in gymnosperms. Gymnosperms do not need root pressure to get water from soil as they are mainly grown in cold and dry climates. Thus gymnosperms lack companion cells.
The companion cells are vertically elongated in structure and angular in cross section.
Note:
Companion cells are present only in angiosperms. Pteridophytes and gymnosperms do not have companion cells but some of them have some cells with similar functions (called albuminous cells). However there is no relationship between sieve cells and albuminous cells.
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