Sign In

34.21 : The Apoplast and Symplast

Plant growth depends on its ability to take up water and dissolved minerals from the soil. The root system of every plant is equipped with the necessary tissues to facilitate the entry of water and solutes. The plant tissues involved in the transport of water and minerals have two major compartments - the apoplast and the symplast. The apoplast includes everything outside the plasma membrane of living cells and consists of cell walls, extracellular spaces, xylem, phloem, and tracheids. The symplast, in contrast, consists of the entire cytosol of all living plant cells and the plasmodesmata - which are the cytoplasmic channels interconnecting the cells.

There are several potential pathways for molecules to move through the plant tissues: The apoplastic, symplastic, or transmembrane pathways. The apoplastic pathway involves the movement of water and dissolved minerals along cell walls and extracellular spaces. In the symplastic route, water and solutes move along the cytosol. Once in this pathway, materials need to cross the plasma membrane when moving from cell to neighboring cell, and they do this via the plasmodesmata. Alternatively, in the transmembrane route, the dissolved minerals and water move from cell to cell by crossing the cell wall to exit one cell and enter the next. These three pathways are not mutually exclusive, and some solutes may use more than one route to varying degrees.

Another potential route is the vacuolar pathway, but this route is mostly restricted to water molecule movement. Here, water moves through the vacuoles of plant cells through osmosis. The mechanism is similar to the symplastic route, but instead of transport being limited to the cytosol, the water passes through the vacuoles. Further, vacuolar transport is facilitated by two proton pumps - ATPase and PPase - that energize the solute uptake. Vacuoles also comprise of specialized transport proteins - the aquaporins - that participate in the transport of water and solutes such as glucose and sucrose.

Tags
ApoplastSymplastWater TransportMineral TransportExtracellular SpacesCell WallsAir SpacesPlasma MembranesPH ChangesExcretion Of ProtonsToxinsCytoplasmInterconnected Plant CellsSignal MoleculesHormonesCytokininCell ProliferationSmall RNAsDefense ResponsesPlant PathogensSelectively Permeable MembranePlant Growth

From Chapter 34:

article

Now Playing

34.21 : The Apoplast and Symplast

Plant Structure, Growth, and Nutrition

47.1K Views

article

34.1 : Introduction to Plant Diversity

Plant Structure, Growth, and Nutrition

41.4K Views

article

34.2 : Non-vascular Seedless Plants

Plant Structure, Growth, and Nutrition

59.3K Views

article

34.3 : Seedless Vascular Plants

Plant Structure, Growth, and Nutrition

55.5K Views

article

34.4 : Introduction to Seed Plants

Plant Structure, Growth, and Nutrition

54.5K Views

article

34.5 : Basic Plant Anatomy: Roots, Stems, and Leaves

Plant Structure, Growth, and Nutrition

51.5K Views

article

34.6 : Plant Cells and Tissues

Plant Structure, Growth, and Nutrition

51.8K Views

article

34.7 : Meristems and Plant Growth

Plant Structure, Growth, and Nutrition

38.2K Views

article

34.8 : Primary and Secondary Growth in Roots and Shoots

Plant Structure, Growth, and Nutrition

49.3K Views

article

34.9 : Morphogenesis

Plant Structure, Growth, and Nutrition

22.6K Views

article

34.10 : Light Acquisition

Plant Structure, Growth, and Nutrition

8.1K Views

article

34.11 : Water and Mineral Acquisition

Plant Structure, Growth, and Nutrition

27.1K Views

article

34.12 : Short-distance Transport of Resources

Plant Structure, Growth, and Nutrition

14.9K Views

article

34.13 : Xylem and Transpiration-driven Transport of Resources

Plant Structure, Growth, and Nutrition

21.9K Views

article

34.14 : Regulation of Transpiration by Stomata

Plant Structure, Growth, and Nutrition

26.6K Views

See More

JoVE Logo

Privacy

Terms of Use

Policies

Research

Education

ABOUT JoVE

Copyright © 2025 MyJoVE Corporation. All rights reserved