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All the following statements regarding sieve tube elements are true except |
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a) |
Their end walls have perforated sieve plates which become impregnated with lignin at maturity |
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b) |
They possess peripheral cytoplasm as well as a large vacuole |
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c) |
Distinct proteinaceous inclusions, the P-proteins are seen evenly distributed throughout the lumen |
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d) |
Long, slender, tube-like structures arranged in longitudinal series |
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All the following statements regarding sieve tube elements are true except |
|
|
a) |
Their end walls have perforated sieve plates which become impregnated with lignin at maturity |
|
b) |
They possess peripheral cytoplasm as well as a large vacuole |
|
c) |
Distinct proteinaceous inclusions, the P-proteins are seen evenly distributed throughout the lumen |
|
d) |
Long, slender, tube-like structures arranged in longitudinal series |
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(a) 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. The end walls are generally bulged out. They may be transverse or oblique. They have many small pores or sieve pits. Each sieve pore is lined by a layer of callose. Due to the presence of sieve pits. The end walls are commonly called sieve plates |