Submitted: April 7th, 2005
What is endocytosis and its role in nutrient uptake?
Endocytosis is an active transport mechanism of larger molecules, particles or bacteria (that are too large to pass through the cell membrane the ion ways) into the cell cytoplasm.
Molecules pass the cell wall to reach the cell membrane and settle at the surface. The plasma membrane vaginates the molecules and forms a coated vessel. This vessel moves into the cell cytoplasm and embarks at predetermine locations where it releases its content of molecules. The vessel now loads new matter for building cell walls, membranes or to be circulated to other cells.
Until recently, it was thought that only human or animal cells are capable of endocytosis, leading to the belief that nothing larger than ions can cross the cell membrane and therefore the only way of nutrient uptake would be that of mineral ions.
With this premise the concept of "cation exchange" became the accepted theory with the "CEC" as the basis of soil analysis. Newer studies strongly suggest that endocytosis is an inherent feature of higher plants cells including root cells.
Indirect influence of endo/exocytosis in nutrient uptake:
-Root symbiosis with fungus enhancing nutrient uptake and efficiency
-Root symbiosis with nitrogen fixing bacteria by building root nodules
-Other secondary endocytic steps necessary for nutrient uptake
Direct influence of endocytosis in nutrient uptake:
-Direct absorption of larger molecules like amino acids by plant roots thus bypassing mineralization
Actin-dependent fluid-phase endocytosis in inner cortex cells of maize root apices
Exocytosis and Endocytosis
Actinorhizal, mycorhizal and rhizobial symbioses: How much do we know? (.pdf)
Plant nitrogen uptake
special thanks to medical grade
Disclaimer: Information in this text may not be completely correct. This text is meant as a starting point for further study.
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