Category : 7th Class
Inside the plant body, mainly three types of materials are transported. These are water containing minerals, digested food, and hormones. In plants two systems are involved in transportation, namely:
Transportation of Water and Minerals
The system, which is responsible for transportation of water and minerals is called xylem. Let us know about the xylem..
Xylem is responsible for transportation of water and minerals. Water and mineral absorbed by the roots of a plant is transferred to the leaves by xylem. The transport system, xylem, is made up of two kinds of elements:
Xylem vessels are made up of long dead cells. In the xylem vessels, dead cellsare joined with each other. And at the joint, cell wall is broken down. Thus atube like structure is formed and water and minerals absorbed by the root hairget a way to reach to the leaves.
Tracheids are also dead cells but they have the tapering ends rather than open. Therefore they do no form the vessels. The transportation of water from one dead cell to another occurs through pits present in their cell walls. Tracheids are water conducting tissues in only non-flowering plant.
Work of Root Hair
The job of root hair is to absorb the water and to take it to xylem tube. Xylem tubes reach to every leaves of the plant. So when water enters into xylem, it is transported to the required parts.
Which one of the following statements is not true?
(a) Water enters into xylem vessels through root hairs
(b) Root hairs lie in between soil particles
(c) The cells of xylem vessels have tapering end
(d) Cells of xylem vessels are joined with open ends
(e) None of these
Transportation of water from one tracheid to another takes place through their tapering ends".
Read the above statement and select by which one of the following options, "tapering end 'given in the statement should be replaced?
(a) Vessels formed by the dead cells
(b) Flat ends of the tracheid cells joined together
(c) Pits present on the cell
(d) Selectively permeable cell wall
(e) None of these
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