AP BIOLOGY

Detailed explanation-1: -Translocation, or the transport of dissolved elements in a plant, transports sap through the phloem. Unlike xylem, which can only transport water upward, phloem may transport sap both uphill and downward, from sugar sources to sugar sinks: Plant organs that produce sugars, such as leaves, are sugar sources.

Detailed explanation-2: -The upward movement of water and minerals from the root to the top of the plant is called as ascent of sap. Plants absorb water through the root hairs and transpire through leaves. The water moves from the root to the tip portion of the plant body against the force of gravity by transpiration pull.

Detailed explanation-3: -Hold a leaf up to the sun and you will clearly see the veins used for fluid transport in the plant. Both the phloem and xylem forms of sap flow through these veins. Sap is the life’s blood of a plant.

Detailed explanation-4: -The phloem carries food downward from the leaves to the roots. Xylem cells constitute the major part of a mature woody stem or root. They are stacked end to end in the center of the plant, forming a vertical column that conducts water and minerals absorbed by the roots upward through the stem to the leaves.