November 6, 2007 Chapter 42 Transport of Sugars • Sugars must be moved form leaves to non-photosynthetic parts of plants o Sugars are moved through the phloem o Pressure-flow theory • Botanists gained two pieces of information by studying aphids that feed on sieve tube fluid o Phloem fluid contains 10%-25% sugars • Pressure-flow theory o Fluid transport in phloem of angiosperms o Differences in water pressure drive sap through phloem sieve tubes o Sugars are transport from sources and sinks o A source is and structure that synthesizes sugars or coverts starch to sugar Mature leaves o A sink is any structure that uses up sugar or convert sugar to starch Newly forming leaves, growing roots, buds, stems, and developing fruits o Storage organs (tubers, bulbs) may be sources or sinks depending on the
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This note was uploaded on 04/10/2008 for the course BIOLOGY 101 taught by Professor Beitch during the Spring '07 term at Quinnipiac.