Leaves

• Hydathodes: Specialized openings or pores located along the leaf margins, facilitating the excretion of excess water through guttation.
• Dicot Leaf

  Dicot leaves exhibit reticulate venation (network-like pattern).

  • Lamina: The flat, expanded portion of the leaf, commonly referred to as the blade. It consists of various parts including:
  • Apex: Tip of the leaf.
  • Margin: Edge of the leaf.
  • Midrib: Central vein.
  • Veins: Network of veins branching from the midrib.
  • Base: Bottom of the leaf.
  • Petiole: The stalk that attaches the leaf to the stem.
  • Axillary Bud: Bud located at the angle between the stem and the leaf.
  • Stipule: Small leaf-like structures found at the base of the petiole in some dicots.
• Monocot Leaf:

  Monocot leaves exhibit parallel venation, with veins running parallel to each other.

  • Sheath: The part of the leaf that wraps around the stem, holding the leaf to the plant.
  • Auricle: Two flaps of leaf tissue extending around the stem at the juncture between the sheath and blade.
  • Ligule: A small flap of tissue extending upward from the sheath.
  • Collar: The area between the sheath and blade, with auricles and ligules on the inside.
• What is the primary function of the epidermis in plants?

  Provides protection and secretes cutin to prevent water loss
• Where are stomata primarily located?

  In the lower epidermis
• What are the main components of the dermal tissue system in leaves?

  • Epidermis: Outermost layer of cells
  • Cuticle: Waxy layer preventing water loss
  • Stomata: Small pores for gas exchange
  • Guard Cells: Regulate stomatal opening and closing
• Where is the phloem located in the vascular bundle?

  On the lower side of the vascular bundle
• Ground Tissue System (Mesophyll)

  • The ground tissue system is composed of photosynthetic tissues called the mesophyll, which means "middle of the leaf."
  • Palisade Mesophyll: Consists of vertically elongated, compact parenchyma cells, densely packed with chloroplasts; the main site for photosynthesis.
  • Spongy Mesophyll: Loosely arranged cells with air spaces that allow for the diffusion of gases
• Vascular Tissue System

  • Veins (Vascular Bundles): Responsible for the transport of water, minerals, and nutrients.
  • Xylem: Located on the upper side of the vascular bundle
  • Phloem: Located on the lower side of the vascular bundle
  • Bundle Sheath: A layer of parenchyma or sclerenchyma cells that surrounds the vascular bundle, providing structural support and protection.
• Simple Leaves:

  • A simple leaf is characterized by a single continuous leaf blade attached to the stem via a petiole.
  • There is no division into leaflets, and the leaf blade is a single unit.
  • Example: Maple leaf is a classic example of a simple leaf.
• Compound Leaves:

  • A compound leaf consists of multiple leaflets arising from the same petiole.
  • Pinnately Compound:
  • Leaflets are arranged on both sides of a central axis called a rachis.
  • Palmately Compound:
  • The leaflets radiate from a single central point
• Alternate: One leaf grows at each node, alternating sides along the stem.

  Opposite: Two leaves grow directly opposite each other at each node.

  Whorled: Three or more leaves grow in a circle at each node.

  Rosette: Leaves are arranged in a circular cluster, often at the base of the plant.
• What do bud scales cover and protect?

  They cover the delicate meristematic tissue of buds.
• What is the primary function of tendrils in plants?

  Tendrils aid plants in climbing and providing support.
• What are colorful bracts associated with?

  They are associated with flowers or inflorescences.
• What is the structure of bulbs in plants?

  Bulbs are rounded, fleshy underground structures composed of short stems with fleshy leaves.
• What is the function of prickles, thorns, and spines in plants?

  They serve a protective function by deterring herbivores.
• Which plant has spines as a protective feature?

  Cacti have spines.
• Which plant has prickles as a protective feature?

  Roses have prickles.
• 1. Netted or Reticulate Venation:

  • A common venation pattern where the veins form a mesh-like network. This is typical in dicots.
  • Two types:
  • Pinnately Veined: A single main vein called a midrib runs down the center with smaller secondary veins branching off.
  • Palmately Veined: Multiple veins radiate outward from the base of the leaf blade.

  1. Parallel Venation:

  • Veins run parallel to each other from the base to the tip of the leaf. This type is common in monocots.

  1. Dichotomous Venation:

  • There is no main vein. The veins fork evenly from the base to the edges of the leaf, forming a fan-like structure.