Translocation moves sugar from a source
   to a sink via phloem.
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<Li> Loading  of  sugar into the sieve tube at the source reduces water
potential  inside  the sieve-tube. This causes the tube to take up
water by osmosis.
<Li> Uptake of water generates positive pressure that forces the sap to
flow along the tube.
<Li> The  pressure is relieved by the unloading of sugar and water from
the tube at the sink.
<Li> Xylem recycles water from sink to source.
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   Translocation in summer:  <A ClAsS=MID Href="../../../med/Vid/Campbell8e/36_Animations/36_20PhloemTranslocSummer_A.swf" oNClick="popurlt('../../../../med/Vid/Campbell8e/36_Animations/36_20PhloemTranslocSummer_A.swf');txtcolor('translocation1','gray');return false;" Id=translocation1><iMg sRc="/images/shockwave.gif" aLt='' boRDer=0></A>
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   Translocation in spring:  <A ClAsS=MID Href="../../../med/Vid/Campbell8e/36_Animations/36_20PhloemTranslocSpring_A.swf" oNClick="popurlt('../../../../med/Vid/Campbell8e/36_Animations/36_20PhloemTranslocSpring_A.swf');txtcolor('translocation2','gray');return false;" Id=translocation2><iMg sRc="/images/shockwave.gif" aLt='' boRDer=0></A>
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