Lec8Translocationnotes

3 5 gcm2hr translocation factors affecting source

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Unformatted text preview: s leave sieve tubes by sink utilization water moves out Translocation causes some high presusre pumping using atp Source-Sink Interactions • Specific Mass Transfer (SMT) – Weight of assimilate moved per cross-sectional area of phloem per unit time – Ranges between 3-5 g/cm2/hr Translocation Factors Affecting Source-Sink Interactions • Proximity • Sink strength changes during development – Leaf starts as sink – When leaf is 40-50% expanded it becomes a source – Sink strength = sink size x sink activity • Sink size = total weight of sink tissue • Sink activity = rate of uptake of photosynthate – Less sugar translocated to ear of wheat when some grains are removed Translocation Factors Affecting Source-Sink Interactions • Source leaves supply sinks with which they have direct vascular connections Translocation Factors Affecting Source-Sink Interactions • Wounding or pruning can interfere with source-sink translocation pathways – Girdling • Air layering • Phloem size seems to develop according to the size of the source or sink it serves. Translocation http://aggiehttp://generalhorticulture.tamu.edu/ horticulture.tamu.edu/earthkind/landscape/ air-layering/ Factors Affecting Source-Sink Interactions • Sink removal Translocation Photosynthate Distribution • Allocation* (within cell) – The regulatio...
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