Plant Systems Overview and Root Structure

Plant Systems Overview

• Plants are multicellular organisms, typically green due to chlorophyll, and immobile.
• Flowering plants differ structurally from mosses, ferns, and conifers.
• Plant systems are categorized into root and foliaceous (leaf) systems.
• Plants produce their own food through photosynthesis.
• Plants do not require complex systems like digestion, movement, or a nervous system.
• Plants' essential functions include gas exchange and circulation.
• Roots are usually below ground, absorbing majority of water and minerals.

Root System

• The root system anchors the plant, often extending extensively underground.
• Roots absorb water and minerals.
• Roots form a complex structure of dermal, fundamental, and vascular tissues to fulfill these roles.
• Roots are a valuable food source, including carrots and sugar beets.

Plant Tissues

• Plant tissues include dermal, fundamental, and vascular tissues.
• Dermal tissues form the outer layer and include epidermal and peridermal tissues.
• Epidermal tissue is a thin outer layer covering non-woody parts.
• Peridermal tissue forms bark on stems and roots.
• Dermal tissues absorb water and minerals, create a waxy surface for protection, and produce defensive structures like hairs containing irritants.
• Fundamental tissues perform various functions depending on location.
• Vascular tissues (xylem and phloem) are responsible for transport.
  • Xylem transports water and minerals upwards.
  • Phloem transports sugars (glucose) and hormones throughout the plant.
• Vascular tissues connect dermal and fundamental tissues, and store nutrients in roots and stems.

Plant Growth

• Plant growth involves apical and secondary meristems.
• Apical meristems are regions of cell division, contributing to growth.
  • Elongation region: cells lengthen.
  • Maturation region: cells specialize into tissues.
• Secondary meristems enable diameter growth.
• Secondary merstems produce new layers of dermal tissue (cork), inner phloem, and inner xylem.

Plant Parts and Their Roles

• Plant parts include stems, roots, and leaves.
• Leaves are the primary photosynthetic organs.
  • They use light energy, carbon dioxide, and water to produce glucose and oxygen.
  • Contain chloroplasts with thylakoids for photosynthesis.
• Flowers are reproductive organs.
  • Contain male (pollen) and/or female (ovules) reproductive structures.
  • Fertilization leads to seed production within the fruit.
• Stems support leaves, flowers, and transport substances between roots and leaves.

Photosynthesis and Cellular Respiration

• Photosynthesis: Plants use solar energy, water, and carbon dioxide to produce glucose and oxygen.
• Cellular Respiration: Cells break down glucose in the presence of oxygen to create ATP (energy), releasing carbon dioxide and water as byproducts.