1.Give the most appropriate term for the following : a.The only living component of xylem. b.The only dead component of phloem. c.The permanent tissue which develops thick walls due to deposition of lignin. 2. Tick the correct option: a. Phloem-movement of water, movement of food b. The annual rings in a tree are actually - xylem rings, phloem rings 3. Give reasons: Xylem and phloem are referred to as complex tissue. 4. The hard walnut shells and gritty masses in the skin and pulp of pears are made up of _______cells.
Answers
Answer:
In stems and leaves of monocots, collenchyma is absent. Instead, sclerenchyma is present in monocots. Xylem parenchyma consists of living cells of parenchyma, which are thick and their secondary cell wall is lignified. Sieve tube member is associated with one or more specialized parenchyma cells called as companion cells. Phloem fibres are generally present in the secondary phloem.
Explanation:
✏1) Appropriate terms
- a) Xylem parenchyma
They are only living cells in xylem tissue which helps in the storage of food and radial conduction of water and minerals.
- b) Phloem fibres
The phloem fibres are dead sclerenchymatous tissue. They are the sources of plant fibres like Hemp, jute etc.
- c) Sclerenchyma
The Sclerenchyma cells are dead, narrow and long cells. Their walls are greatly thickened with deposition of lignin. Hence, their cell walls are known as lignified walls.
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✔2) Correct answer:
- Phloem - Movement of food
The pphloem transport photosynthesized prepared food in both directions from leaves to all parts. The transport bidirectionally. They are formed of sieve tubes, companion cells, phloem parenchyma and phloem fibres.
- Annual rings - Xylem tissue
The Xylem rings are formed annually. They are used in determining the age of the plant, by just just counting the rings.
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✏3) Give reasons:
The Xylem and Phloem tissue are known as Complex tissue, because they are made up of more than one kind of cells. All these cells, coordinate together to perform a specific function like transportation of water and minerals, or translocation of food.
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✒ 4) The answer is Sclerenchyma(sclereids). They are highly thickened and irregularly shaped ded cells. They are found in found in various parts of the plant such as in the cortex, hard seedcoats etc. They provide strength and grittiness to the pulp of many fruits and seeds like guava, apple and pear. Also, the wall coat of seeds and nuts.
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