FORESTRY
PLANT AND WOOD ANATOMY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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a and b
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a and c
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b and c
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a b and c
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Detailed explanation-1: -Sieve tubes are tubular cells with perforated walls. They are living but do not have a nucleus and are the important component of phloem. Phloem parenchyma and companion cells are elements of phloem and both are living cells.
Detailed explanation-2: -Sieve tubes are considered living cells without a nucleus because the nucleus of companion cells controls their functional activities. Companion cells, which unite with sieve tubes to form the sieve element-companion cell complex, are related to sieve-tube members.
Detailed explanation-3: -Sieve tubes are elongated tubular conducting channels of phloem. Each sieve tube is formed of several cells called sieve tube members, sieve tube cells or sieve elements. Sieve tube members are placed end to end.
Detailed explanation-4: -The sieve tube members are living cells (which do not contain a nucleus) that are responsible for transporting carbohydrates throughout the plant. Sieve tube members are associated with companion cells, which are cells that combine with sieve tubes to create the sieve element-companion cell complex.