Fri February 20, 2009 By: harshit...............

Expert Reply
Sat February 21, 2009

Translocation i.e. transport of soluble products of photosynthesis, occurs in the part of the vascular tissue called phloem. It takes place in the sieve tubes with the help of adjacent companion cells both in upward and downward directions. Translocation in phloem is achieved by utilising energy. Material like sucrose is transferred into phloem using energy from ATP. This increases the osmotic pressure of the tissue causing water to move into it. This pressure moves the material in the phloem to tissues which have less pressure. Thus the phloem can move material according to the plant's needs.

Water and minerals absorbed by the root are transported upwards through the xylem. Transport in xylem can be largely explained by simple physical forces and do not require energy.

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