1 / 8

Phloem loading: Sink/ source vs. Productivity

Phloem loading: Sink/ source vs. Productivity. Symplast vs. apoplast pathways: distinguish at near the sieve element-companion cell complex.  s -1.3 MPa.  s -3.0 MPa. or transfer cells. apoplast: suc major selective transporter energy required: respiratory inhibitors,

kina
Télécharger la présentation

Phloem loading: Sink/ source vs. Productivity

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. Phloem loading: Sink/source vs. Productivity Symplast vs. apoplast pathways: distinguish at near the sieve element-companion cell complex s -1.3 MPa s -3.0 MPa or transfer cells apoplast: suc major selective transporter energy required: respiratory inhibitors, active loading Organic acids, hormones  passive symplast: suc and others, such as raffinose and stachyose

  2. Sucrose-H+ symporter  in the apoplast of phloem loading  in the membrane of company cells or sieve elements  dissipate proton energy to couple the uptake of sucrose CC SE

  3. Regulating sucrose loading by the sucrose-H+ symporter — are not completely clear  The turgor pressure of the sieve elements below a threshold level, a compensatory increase loading?  Sucrose concentration in the apoplast [Suc]apoplast?  The available No. of symporter molecules feed Suc  SUT1 transcription, SUT1 and itsmRNA rapidly degrade, protein phosphorylation involved a diurnal regulation  Nutrient supply— potassium availability enhance sucrose efflux into apoplast  sink growth

  4. Intermediary cellsin thesymplastof phloem loading ¤ diffusion ¤ raffinose, stachyose, in addition to sucrose ¤ apolymer-trapping model

  5. The type of phloem loading is corrected withplant familyand withclimate herbaceous trees, shrubs, vines temperate and arid tropic and subtropic exceptions Coexist New loading ? Symplastic loading advantages?

  6. Phloem unloading and short-distance transport — via symplast or apoplast PCMB: inhibit sucrose across membrane

  7. The transition of a leaf from sink to source Squash Feed 14C on source leaf for 2 h source leaf sink leaf The base still a sink sink  source depend on species, 25% → 40-50% The cessation of import and the initiation of export are independent events. The extent of maturation and sampling position

More Related