The apoplast is a network of cell walls and intercellular spaces in plants that allows for the movement of water and solutes. It is part of the plant's transport system, functioning outside the cell membranes. This pathway enables substances to travel through the plant without entering the living cells, facilitating efficient nutrient and water distribution. In addition to water transport, the apoplast plays a role in plant defense. It can act as a barrier against pathogens, as many harmful microorganisms cannot easily penetrate the cell walls. This protective function is crucial for maintaining plant health and resilience against environmental stressors.