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Vertical growth (up-down), dominant direction in most plants.
Secondary LateralMeristem
Horizontal growth (left-right), adds layers to the plantthickening stems and roots.
• Meristem: Unspecialized embryonic plant tissue found in areas of growth Apical Meristem: Type of primary meristem located at the tip of stems or roots
where cell division occurs. Vascular Cambium: Lateral meristem found in stems that develops into secondary
Type Region DescriptionDermal Outer Outer region made up of dead cells that act as a protective
covering aginst the environment and water loss.
Ground Contains parenchyma, collenchyma, and sclerenchyma.Performs photosynthesis and adds to structural support.
Parenchyma(Youngest)
Thin-walled cells found in mostly in younger sections of plants. Most of photosynthesis occurs in these cells
Collenchyma(Mid-aged)
Supporting cells with thicker walls that make up much of thestem.
Sclerenchyma(Oldest)
Mid
Rigid dead support cells with a secondary cell wall. The pithand bark are made up of these cells
Vascular Inner Center tissue responsible for transporting water and otherminerals.
Transportation Structures
• Water Potential: Determines direction of osmosis (high to low)
Water Potential (ΨΨΨΨ)
Value (ΨΨΨΨ)))) Solute Level Description
(-) Negative Higher Water is absorbed from surrounding environment
(0) Zero Same Potential of pure water, no amount is lost or gained
(+) Positive Lower Water is lost to surrounding environment
• Transpiration Pull: Accounts for water movement up the xylem. Water lost fromevaporation causes extremely low (negative) water potential towards the top of the plant.Water diffuses upwards, providing the necessary reactant for photosynthesis withoutexpending energy.
• Translocation: (Pressure Flow Hypothesis) Movement of sugar from “sources” to “sinks”during the build-up of pressure when a high concentration of sugar draws in water.