The anatomy of flowering plants includes different types of tissues and their specialized functions. In meristematic tissues, the cells actively divide throughout their life and remain young forever. Permanent tissues are the mature tissues which have lost the ability to divide and attained a permanent shape. The secretory tissues perform the function of secretion.
Q.1. Where is the product of photosynthesis stored?
Q.2. What cells curl the leaves in plants during water stress?
A.2. Bulliform cells present in the upper epidermis of monocot leaves make the leaves curl during water stress.
Q.3. What is a cambial ring comprised of?
A.3. Cambium is a layer of actively dividing cells between the xylem and phloem tissues which is responsible for the secondary growth of roots and stem.
Q.4. If a tree is debarked, what part of the plant is being removed?
A.4. All the tissues external to the vascular cambium including the secondary phloem are removed.
Q.5. Differentiate between hardwood and softwood.
|Angiospermic wood||Gymnospermic wood|
|Tracheids are absent||Vessels are absent|
|Contains vessels||Contains tracheids|
Q.6. How is a cork formed in the plant? What is its commercial source?
A.6. The cork is formed by phellogen or cork cambium. The tissue of tannin, dead, and air-filled suberised cells formed on the outer side of phellogen is called cork.
Cork oak or Quercus suber is the commercial source of oak.
Q.7. What are the differences between lenticels and stomata?
|Minute pores found on the epidermis of the leaves.||Pores present on the tree trunk or the stem of the plant.|
|The opening and closing of stomata can be regulated.||The lenticels are always open.|
|These possess guard cells.||These do not possess guard cells.|
|They facilitate transpiration and exchange of gases.||These are only responsible for the exchange of gases.|
|Active during the day.||Active during the night.|
|The stomatal guard cells contain chlorophyll that helps in photosynthesis.||Lenticels cannot photosynthesize|
|A large amount of water vapour is emitted through the stomata.||A small amount of water vapour is released through the lenticels.|
|Not found in roots and fruits.||Found in roots and fruits.|
Q.8. Why do plants die when water excessively?
A.8. Over-watering drowns the plant and blocks the air pockets. Thus the roots do not get enough air to breathe. That is why the plants die in excessive water.
Q.9. Why and how do Palm increase in girth despite being a monocotyledonous plant?
A.9. The parenchymatous cells in the ground tissue enlarge and divide. Thus, due to repeated division, the girth of the stem increases and is known as diffused secondary growth.
Q.10. Is Pinus an evergreen tree?
A.10. Evergreen plants have leaves throughout the year. Pinus belongs to the gymnosperm group. Pinus has a thick bark, and needle-like leaves to reduce the rate of transpiration. Pinus is well-adapted to low temperatures. It continues to prepare its food even in very cold conditions and does not shed its leaves.
Q.11. Why are phloem and xylem complex tissues?
A.11. Xylem and phloem are made up of more than one type of cells. These cells function in coordination to perform various functions.
Xylem conducts water and minerals and provides support to the plant. It is made up of tracheids, xylem parenchyma, and xylem fibres. Phloem conducts food materials to various parts of the plant. It comprises of sieve tubes, phloem parenchyma, companion cells, and phloem fibres. That is why they are known as complex tissues.
Q.12. State the differences between the guard cells and epidermal cells. Which epidermal cell surrounds the guard cell?
A.12. The epidermal cells surrounding the guard cells are called subsidiary cells.
Following are the differences between the guard cells and the epidermal cells:
|Guard Cells||Epidermal Cells|
|Smaller in size.||Larger in size.|
|Contain chloroplast.||Do not contain chloroplast.|
|The cell wall is non-uniform and thick.||The cell wall is uniform and thin.|
Q.13. How are growth rings in a tree trunk formed? What is its importance?
A.13. The growth rings are concentric rings also known as annual rings. Secondary growth gives rise to these rings. Secondary growth occurs due to the activity of meristematic tissue, cambium.
By counting these rings one can determine the age of the tree.
Q.14. Name the modifications of epidermal cells and the functions performed by them.
A.14. Following are the modifications of the epidermal cells:
The root hair consists of unicellular hair extending from the epidermal cells.
It increases the surface area for the absorption of water and materials.
They may be unicellular or multicellular. These are also known as trichomes.
They defend the plant against insects. They help in lowering the plant temperature and reduce water loss.
Q.15. From which part of the plant are these plant fibres obtained?
- Jute- Corchoruscapsularis
- Hemp- Stem of Cannabis sativa
- Cotton- Gossypiumhirsutum seed
- Coir- Coconut Husk
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