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प्रश्न
Explain how sieve tubes manage to be living?
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उत्तर
Sieve tube elements of phloem tissue lack nucleus but still they manage to live. This is because they are connected to the companion cells of phloem tissue via numerous plasmodesmata. Both sieve tube elements and companion cells develop from the same meristematic cell and form a functional unit. Companion cells provide proteins, ATP, and other signalling molecules to the sieve tube member as it contains extra number of mitochondria and ribosomes
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संबंधित प्रश्न
Differentiate between:
Collenchyma and Sclerenchyma
Give the structure and function of the following:
Sclerenchyma
Write 'True or False' for the following statement:
A vascular bundle conducts prepared food only.
The question has four answers. Choose the correct answer:
Hard lignified thick walled, long and pointed cells in a plant are
The question has four answers. Choose the correct answer:
A component of xylem is
Choose the correct option.
Collenchyma is a type of ______ tissue.
What are sieve tubes? Explain.
Match the column (A) with the column (B)
| (A) | (B) | ||
| (a) | Parenchyma | (i) | Thin walled, packing cells |
| (b) | Photosynthesis | (ii) | Carbon fixation |
| (c) | Aerenchyma | (iii) | Localized thickenings |
| (d) | Collenchyma | (iv) | Buoyancy |
| (e) | Permanent tissue | (v) | Sclerenchyma |
Differentiate between meristematic and permanent tissues in plants
Cells of this tissue are living and show angular wall thickening. They also provide mechanical support. The tissue is ______.
