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प्रश्न
Explain different types of elements present in phloem.
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उत्तर
Phloem consists of following four elements:
(i) Sieve tubes: These are slender, tube-like structures composed of elongated thin walls placed end to end. Their end walls, sieve plate, are perforated by large number of pores. Sieve tube elements lack nuclei, but they remain alive via adjacent companion cells.
(ii) Companion cells: They are connected with the sieve tubes via plasmodesmata. They are thin-walled cells consisting of dense and active cytoplasm and large, elongated nucleus.
(iii) Phloem parenchyma: As the name suggest, they consist of living parenchyma cells. They are involved in storage and lateral conduction of food.
(iv) Phloem fibres or bast fibres: These are dead cells of phloem possessing a narrow lumen. They are meant for providing mechanical support to the phloem.
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संबंधित प्रश्न
What are simple tissues?
Parenchyma containing chloroplasts is known as :
Study the diagram given below and then answer the question that follows:
Where is this tissue likely to be found in the plant?
Give the structure and function of the following:
Sclerenchyma
Give the structure and function of the following:
Collenchyma
Why the cells of sclerenchyma and tracheids become dead?
Explain sclereids with their types.
Name the two types of sclerenchyma cells.
Which of the following is a permanent tissue?
Match the followings and choose the correct option from below
| Column I | Column II |
| A. Meristem | i. Photosynthesis, storage |
| B. Parenchyma | ii. Mechanical support |
| C. Collenchyma | iii. Actively dividing cells |
| D. Sclerenchyma | iv. Stomata |
| E. Epidermal tissue | v. Sclereids |
