Plant Nutrient Transport Systems and Anatomy

Nutrient Transport Vessels

The transport of nutrients in plants is managed by a system of carrying vessels. These vessels are formed by:

• Xylem: Composed of raw sap, it moves from the root to the top of the plant.
• Phloem: Formed by elaborated sap, it ranges from the upper part to the root of the plant.

Root Functions and Structure

Root Functions

1. Supports and fixes the plant to the ground.
2. Absorbs the nutrients needed for plant growth.
3. Stores and transports water throughout the plant.

Parts of the Root

The root is the part of the plant that grows into the center of the earth and sustains the plant.

• Collar: The part of the root located on the land surface; it is the area that joins the root to the stem.
• Main root: The primary root which holds the plant.
• Secondary roots: Smaller roots that originate from the main root.
• Cap: The end of the root that can penetrate the earth and rock.

Stem Anatomy and Purpose

The stem is the part of the plant that grows against gravity above the soil.

Parts of the Stem

• Nodes (Knots): Points where the stem thickens to form buds or leaves.
• Internodes: The spaces between the nodes where leaves or branches are absent.
• Buds: Areas where growth can originate branches or leaves.
• Terminal bud: Located at the ends of the stem, allowing the stem to elongate.
• Auxiliary bud: Located on the sides of the stem, allowing the growth of side branches or leaves.

Stem Functions

Its functions include support, transporting, storing, and photosynthesis.

Leaf Structure and Physiology

The leaf is the aerial organ of the plant.

Parts of the Leaf

• Petiole: The elongated structure that joins the leaf with the stem.
• Beam (Adaxial): The dorsal surface of the leaf.
• Underside (Abaxial): The ventral surface of the leaf.
• Venation (Nervature): The veins of the leaf through which conducting vessels, such as the phloem and xylem, pass.
• Edge: The end of the blade (limbo).
• Apex: The upper end of the leaf.

Leaf Functions

Its functions include transpiration and photosynthesis.

Cellular Transport and Osmotic Solutions

Hypotonic Solutions

A hypotonic medium has less solute than the medium it is compared with. It contains a lesser amount of solute and more solvent or water. An example of this medium is the turgor that plants experience when incorporating liquids that are hypotonic with respect to their environment.

Hypertonic Solutions

A hypertonic medium contains more solute than another in comparison, therefore having less water or solvent. Water tends to move from where there is less solute to where there is more solute. This generates a loss of water, resulting in the phenomenon of plasmolysis, which occurs when the medium loses too much water, as opposed to a hypotonic state.

Passive and Active Transport

• Passive Transport: The movement of substances through a membrane following a concentration gradient, requiring no expenditure of energy.
• Active Transport: Requires energy expenditure to move substances against a gradient, often involving larger molecules.