Symplasmic transport and phloem loading in gymnosperm leaves

Protoplasma
J LiescheA Schulz

Abstract

Despite more than 130 years of research, phloem loading is far from being understood in gymnosperms. In part this is due to the special architecture of their leaves. They differ from angiosperm leaves among others by having a transfusion tissue between bundle sheath and the axial vascular elements. This article reviews the somewhat inaccessible and/or neglected literature and identifies the key points for pre-phloem transport and loading of photoassimilates. The pre-phloem pathway of assimilates is structurally characterized by a high number of plasmodesmata between all cell types starting in the mesophyll and continuing via bundle sheath, transfusion parenchyma, Strasburger cells up to the sieve elements. Occurrence of median cavities and branching indicates that primary plasmodesmata get secondarily modified and multiplied during expansion growth. Only functional tests can elucidate whether this symplasmic pathway is indeed continuous for assimilates, and if phloem loading in gymnosperms is comparable with the symplasmic loading mode in many angiosperm trees. In contrast to angiosperms, the bundle sheath has properties of an endodermis and is equipped with Casparian strips or other wall modifications that form a domain border...Continue Reading

References

Sep 30, 1998·Proceedings of the National Academy of Sciences of the United States of America·R Turgeon, R Medville
Aug 6, 2000·Environmental and Experimental Botany·C SodaC Tani
Mar 26, 2003·Physiologia Plantarum·Xiaoqin WuLukas Schreiber
Oct 7, 2005·Current Opinion in Plant Biology·Insoon Kim, Patricia C Zambryski
May 4, 2006·Annual Review of Plant Biology·Lawren Sack, N Michele Holbrook
Jul 10, 2007·Plant, Cell & Environment·Maciej A ZwienieckiN Michele Holbrook
Mar 10, 2009·Plant Physiology·Nynne Meyn ChristensenKarl Oparka
Apr 29, 2009·Tree Physiology·Ana PinaHelle J Martens
Aug 12, 2009·Proceedings of the National Academy of Sciences of the United States of America·Emilie A Rennie, Robert Turgeon
Sep 15, 2009·Trends in Cell Biology·William J LucasJae-Yean Kim
Oct 23, 2009·Proceedings of the National Academy of Sciences of the United States of America·Cankui Zhang, Robert Turgeon
Mar 5, 2010·Plant Physiology·Robert Turgeon
Nov 17, 2010·Protoplasma·Robert Turgeon, Richard Medville
Dec 3, 2010·Protoplasma·Anna DavidsonRobert Turgeon
Jan 19, 2011·The Plant Journal : for Cell and Molecular Biology·Lidor GilShmuel Wolf
Aug 1, 2001·American Journal of Botany·R TurgeonK C Nixon
Feb 1, 1984·Planta·A C Wille, W J Lucas

❮ Previous
Next ❯

Citations

Mar 17, 2012·Plant Physiology·Johannes Liesche, Alexander Schulz
Oct 10, 2013·Journal of Experimental Botany·Veerle De SchepperKathy Steppe
Jul 8, 2011·Protoplasma·Julien AlassimoneJoop E M Vermeer
May 1, 2012·Protoplasma·Dieter VolkmannDiedrik Menzel
May 15, 2012·Protoplasma·Peter Nick
Sep 1, 2012·Plant, Cell & Environment·Eero NikinmaaTimo Vesala
Oct 18, 2011·Plant, Cell & Environment·Daniel M JohnsonFrederick C Meinzer
Dec 14, 2011·Plant, Cell & Environment·Kåre Hartvig JensenAlexander Schulz
Jan 9, 2015·Proceedings. Biological Sciences·Henrik RonellenfitschEleni Katifori
Apr 22, 2017·Journal of Integrative Plant Biology·Johannes Liesche
Dec 7, 2017·Nature Plants·Jessica A SavageN Michele Holbrook
Feb 7, 2019·American Journal of Botany·Alana R O Chin, Stephen C Sillett
May 17, 2017·Physical Review. E·Hanna RademakerKaare H Jensen
Jun 28, 2017·Proceedings of the National Academy of Sciences of the United States of America·Alice S BredaChristian S Hardtke
Oct 19, 2017·Plant, Cell & Environment·Akihiro OhtsukaHaruhiko Taneda
Oct 16, 2020·Plant, Cell & Environment·Steven A KannenbergJames R Ehleringer
Feb 28, 2021·The New Phytologist·Johannes LiescheTomas Bohr
Jun 10, 2018·American Journal of Botany·Mónica R CarvalhoKarl J Niklas

❮ Previous
Next ❯

Methods Mentioned

BETA
confocal microscopy
electron microscopy

Related Concepts

Trending Feeds

COVID-19

Coronaviruses encompass a large family of viruses that cause the common cold as well as more serious diseases, such as the ongoing outbreak of coronavirus disease 2019 (COVID-19; formally known as 2019-nCoV). Coronaviruses can spread from animals to humans; symptoms include fever, cough, shortness of breath, and breathing difficulties; in more severe cases, infection can lead to death. This feed covers recent research on COVID-19.

Blastomycosis

Blastomycosis fungal infections spread through inhaling Blastomyces dermatitidis spores. Discover the latest research on blastomycosis fungal infections here.

Nuclear Pore Complex in ALS/FTD

Alterations in nucleocytoplasmic transport, controlled by the nuclear pore complex, may be involved in the pathomechanism underlying multiple neurodegenerative diseases including Amyotrophic Lateral Sclerosis and Frontotemporal Dementia. Here is the latest research on the nuclear pore complex in ALS and FTD.

Applications of Molecular Barcoding

The concept of molecular barcoding is that each original DNA or RNA molecule is attached to a unique sequence barcode. Sequence reads having different barcodes represent different original molecules, while sequence reads having the same barcode are results of PCR duplication from one original molecule. Discover the latest research on molecular barcoding here.

Chronic Fatigue Syndrome

Chronic fatigue syndrome is a disease characterized by unexplained disabling fatigue; the pathology of which is incompletely understood. Discover the latest research on chronic fatigue syndrome here.

Evolution of Pluripotency

Pluripotency refers to the ability of a cell to develop into three primary germ cell layers of the embryo. This feed focuses on the mechanisms that underlie the evolution of pluripotency. Here is the latest research.

Position Effect Variegation

Position Effect Variagation occurs when a gene is inactivated due to its positioning near heterochromatic regions within a chromosome. Discover the latest research on Position Effect Variagation here.

STING Receptor Agonists

Stimulator of IFN genes (STING) are a group of transmembrane proteins that are involved in the induction of type I interferon that is important in the innate immune response. The stimulation of STING has been an active area of research in the treatment of cancer and infectious diseases. Here is the latest research on STING receptor agonists.

Microbicide

Microbicides are products that can be applied to vaginal or rectal mucosal surfaces with the goal of preventing, or at least significantly reducing, the transmission of sexually transmitted infections. Here is the latest research on microbicides.