Rucete ✏ Biology In a Nutshell
1. Pathways of Water Movement
a) Apoplast Pathway
- Water moves through cell walls and spaces between cells
- Does not enter the cytoplasm
- Fast and passive route to reach the xylem
b) Symplast Pathway
- Water moves through cytoplasm of plant cells
- Travels via plasmodesmata (cytoplasmic connections between cells)
- More controlled and regulated
2. Mechanisms of Water Movement
a) Osmosis
- Water enters root hairs from the soil via osmosis
- Generates root pressure, a minor force pushing water upward
b) Capillary Action
- Water rises in narrow tubes due to adhesion and surface tension
- Plays a minor role in water transport up the xylem
c) Cohesion-Tension Theory (Transpiration Pull)
- Main driving force for water movement
- Water evaporates from stomata (transpiration), creating a negative pressure
- Water molecules stick together (cohesion), pulling a continuous column upward
- Works like a suction from the leaves
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Biology in a nutshell