Apoplast refers to the extracellular space in plants where water and solutes travel through non-living tissues such as cell walls and intercellular spaces. It is one of the transport pathways in plants, alongside the symplast pathway that involves the movement of substances through living cells via plasmodesmata. The apoplast pathway allows for the movement of water, minerals, and other substances through the spaces between cells without actually crossing any plasma membranes. However, the apoplast pathway does not provide selectivity or regulation of solute movement like the symplast pathway.
The apoplast is the pathway for water and solute movement in plants that occurs outside of the cell. It is composed of the cell walls, extracellular spaces, and the intercellular air spaces within the plant tissues. The movement of solutes and water through the apoplast mainly relies on passive processes such as diffusion and bulk flow. The apoplast plays a significant role in water transport, nutrient uptake, and the movement of signaling molecules within the plant.
