FORESTRY
PLANT AND WOOD ANATOMY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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being nearly dead
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lacking cytoplasm
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Iacking a functional nucleus
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absence of lignified walls
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Detailed explanation-1: -Vessels are the components of xylem, while sieve tubes are present in phloem tissue. The walls of the vessel are lignified i.e., they are made up of lignin. They are extremely hard but not thick. Sieve tube on the other hand, posseses thin cellulosic wall.
Detailed explanation-2: -Mature sieve tube elements are deep, tubular and do not contain nucleus in the cells with no secondary wall and terminal sieve plate. They lack nucleus at the maturity so that they are associated with companion cells for support. Their features are the same as prokaryotic cells.
Detailed explanation-3: -Remember that mature xylem tissue is dead, so there is no evidence of organelles, and they have lignified cell walls, whereas sieve tube elements have no lignin, do have sieve plates, and their companion cells contain nuclei and dense cytoplasm.