1 / 10

Assimilate Transport

Assimilate Transport. Movement of substances through the phloem Chapter 30 . Translocation. movement of substances in phloem in leaf sugars move from chloroplasts to phloem forming the assimilate stream. Movement of assimilate stream in phloem. source to sink movement

alaqua
Download Presentation

Assimilate Transport

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Assimilate Transport Movement of substances through the phloem Chapter 30

  2. Translocation • movement of substances in phloem • in leaf • sugars move from chloroplasts to phloem • forming the assimilate stream

  3. Movement of assimilate stream in phloem • source to sink movement • source – area exporting assimilates • sink – assimilate importing area • What are examples? • Do these change during the life of a plant?

  4. Sour-sink examples • seed manufacture • seed germination • seedling development • vegetative growth • young vs. old • reproductive growth

  5. Sugar Transport in Leaves – evidence via 14C 14CO2 exposure for 35 minutes; 14C incorporated in sugars, confined to sieve tubes

  6. Aphid stylet • content of phloem assimilate • 10-25% dry matter • 90% of dry matter is sugar, mainly sucrose • sieve-tube sap moves at 100cm/hour

  7. Pressure-flow hypothesis • osmotically generated pressure flow • on source end • assimilates transported into sieve tube - phloem loading • as sucrose enters, what happens to water? • water increase raises turgor pressure • on sink end • sucrose is unloaded (removed) from sieve tube – phloem unloading • What happens to water? • thus assimiliate is moved from source to sink by bulk flow

  8. Assimililate movement requires energy

More Related