Plant Transport System Overview

Jul 7, 2025

Overview

This lecture explains how the roots, stem, and leaves function together as a transport system in plants to move water, nutrients, and food throughout the organism.

Roots: Absorption and Transport

  • Roots absorb water and minerals from the soil using tiny hair-like structures.
  • Roots anchor and support the plant and also store food.
  • Water and minerals are passed into the plant’s vascular system, mainly the xylem.
  • Absorption uses processes like capillary action and osmosis.

Stem: Structure and Transport Highway

  • The stem holds the plant upright and provides structural support.
  • The stem transports water and minerals upward through the xylem.
  • It also moves food made in the leaves down through the phloem.
  • The vascular bundle in the stem contains both xylem (center) and phloem (outer part).

Leaves: Food Production and Distribution

  • Leaves perform photosynthesis, using sunlight, carbon dioxide, and water to make glucose.
  • Glucose and other nutrients are transported throughout the plant via the phloem.
  • The leaves send food to all parts of the plant, supporting new growth.

Vascular System: Xylem and Phloem

  • Xylem consists of elongated dead cells with tough, lignin-rich walls; it moves water and minerals up.
  • Phloem is made of living cells and transports sucrose and amino acids in both directions.
  • Movement of substances in the phloem is called translocation.

How Plant Organs Work Together

  • Roots, stems, and leaves collaborate to ensure the plant receives water, minerals, and food.
  • Each part has a specialized role but functions as a team in the plant’s transport system.

Key Terms & Definitions

  • Root — organ that absorbs water/minerals and anchors the plant.
  • Stem — supports the plant and transports fluids between roots and leaves.
  • Leaf — organ responsible for photosynthesis, producing glucose for the plant.
  • Xylem — vascular tissue that transports water and minerals from roots to leaves.
  • Phloem — vascular tissue that moves food (sucrose, amino acids) through the plant.
  • Translocation — movement of food substances in the phloem.
  • Photosynthesis — process where leaves use sunlight, COâ‚‚, and water to make glucose.

Action Items / Next Steps

  • Review the functions of xylem and phloem.
  • Study diagrams of plant vascular bundles.
  • Prepare to describe how roots, stems, and leaves work together in plant transport.