PLANT PHYSIOLOGY
TRANSPORT IN PLANT
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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active loading of water molecules into xylem vessels by endordermis cells
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active loading of salts into xylem vessels by endodermis cells
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xylem vessels using energy to actively load water upwards
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movement of water molecules upwards in xylem vessels through osmosis
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Detailed explanation-1: -Root pressure is caused by active distribution of mineral nutrient ions into the root xylem. Without transpiration to carry the ions up the stem, they accumulate in the root xylem and lower the water potential. Water then diffuses from the soil into the root xylem due to osmosis.
Detailed explanation-2: -root pressure, in plants, force that helps to drive fluids upward into the water-conducting vessels (xylem). It is primarily generated by osmotic pressure in the cells of the roots and can be demonstrated by exudation of fluid when the stem is cut off just aboveground.
Detailed explanation-3: -Force developed in cortex of root which pushes water into xylem of root is root pressure. As various minerals ions from the soil are actively transported into the vascular tissue of the roots, water follows and increase the pressure inside the xylem. This positive pressure is called root pressure.
Detailed explanation-4: -Root pressure is created by the osmotic pressure of xylem sap which is, in turn, created by dissolved minerals and sugars that have been actively transported into the apoplast of the stele. One important example is the sugar maple when, in very early spring, it hydrolyzes the starches stored in its roots into sugar.
Detailed explanation-5: -In plants, nutrients are absorbed through the active and passive transports. The endodermal cells of the roots containing suberin which allow only selected minerals to pass through them. The transport proteins present in the membranes of these cells act as check points for the various solutes reaching the xylem.