Chapter 23, Problem 1MCQ

Summary Introduction

Introduction:

Plant consists of complex conducting tissues for the transportation of water and nutrients internally from part of the plant to the other parts. These conducting tissues are known as vascular tissues. There are two components of vascular tissue: xylem and phloem.

Answer to Problem 1MCQ

Correct answer:

Xylem is that component of conducting tissue which is responsible for the transport of water molecules through a plant internally. Tracheids and vessel elements are the cell types of xylem. Tracheids are the long xylem cells and vessel elements are the short cells which are linked together into long tubes. Sieve tubes are the component of phloem in which water moves by the process of osmosis to the adjacent xylem tissues. Therefore option (d) is the correct answer.

Explanation of Solution

Reason for the correct statement:

Xylem is responsible for the movement of water and minerals through tracheids and vessel elements. Sieve tubes which are the component of phloem tissue are also responsible for the movement of water molecule to the surrounding xylem tissues through osmosis.

Option (d) is given as “all of the above are correct”.

As, “sieve tubes, tracheids and vessel elements are the structures through which water molecule flow as it moves through a plant”, is the right answer.

Hence option (d) is correct.

Reasons for the incorrect statements:

Option (a), is given as “sieve tubes”.

Sieve tubes are involved with the transportation of water through plant. But tracheids and vessel elements are also the correct options. Hence, it is a wrong answer.

Option (b), is given as “tracheids”.

Tracheids are the component of xylem tissue through which water is transported. But sieve tubes and vessel elements are also correct options. Hence, it is a wrong answer.

Option (c), is given as “vessel elements”.

Vessel elements are the short cells of xylem tissue which are linked together to form long tubes called vessels. They also play a part in water transportation. But sieve tubes and tracheids are also correct options. Hence, it is a wrong answer.

Hence options (a), (b), and (c), are incorrect.

Conclusion

Tracheids and vessel elements are the cell types of xylem tissue which is the vascular tissues of plants. The conducting tissue xylem is responsible for moving water molecule from one part of the plant to other. Sieve tubes which are the component of other vascular tissue phloem also play a role in the movement of water from the phloem sap to the xylem tissues.