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Passage cells are thin walled cells found in
A
phloem elements that serve as entry points for substance for transport to other plant parts
B
testa of seeds to enable emergence of growing embryonic axis during seed germination
C
central region of style through which the pollen tube grows towards the ovary
D
endodermis of roots facilitating rapid transport of water from cortex to pericycle
Detailed Solution
The innermost layer of the cortex of a root is called the endodermis. It consists of a single layer of barrel-shaped cells without any intercellular spaces.
The radial and tangential walls of the endodermal cells have a deposition of water-impermeable, waxy suberin in the form of Casparian strips; in older roots most endodermal cells become thick walled.
Some endodermal cells, lying opposite the protoxylem groups, remain thin walled and without these thickenings. They are called passage cells or transfusion cells.
They allow the rapid radial movement of water and dissolved minerals from the cortex into the pericycle and then to the xylem.
Passage cells are not found in phloem, in the testa of seeds or in the style.
So passage cells are thin walled cells found in the endodermis of roots, facilitating rapid transport of water from cortex to pericycle.
The radial and tangential walls of the endodermal cells have a deposition of water-impermeable, waxy suberin in the form of Casparian strips; in older roots most endodermal cells become thick walled.
Some endodermal cells, lying opposite the protoxylem groups, remain thin walled and without these thickenings. They are called passage cells or transfusion cells.
They allow the rapid radial movement of water and dissolved minerals from the cortex into the pericycle and then to the xylem.
Passage cells are not found in phloem, in the testa of seeds or in the style.
So passage cells are thin walled cells found in the endodermis of roots, facilitating rapid transport of water from cortex to pericycle.