Leaf

Leaf Structure and Function

• Leaves are vital organs of vascular plants.
• They are typically broad, flat, and thin to maximize light exposure for photosynthesis.
• Veins supply nutrients and water to cells for photosynthesis.
• Leaf adaptations include reducing light absorption to prevent heat stress.
• Leaves store energy, water, and serve specialized functions like protection and trapping insects.

Leaf Adaptations

• Some plants have adapted leaves to survive in dry conditions (xerophytes).
• Leaves can vary in shape, structure, and thickness based on environmental factors.
• Succulent plants have thick leaves to store water.
• Leaves can also serve as specialized structures like tendrils, spines, or insect traps.

Leaf Internal Structure

• Leaves have evolved internal organization to maximize photosynthesis and carbon dioxide absorption.
• The surface of leaves is waterproofed by a cuticle to control gas exchange.
• Stomata regulate the exchange of CO2, O2, and water vapor.
• Each leaf can have thousands of stomata per square centimeter.
• Leaf shape and structure vary greatly depending on species, climate, and other factors.

Leaf Evolution and Diversity

• Leaves have evolved diverse shapes, sizes, and structures for different functions.
• Leaf types can change within a species based on maturity and environmental conditions.
• Leaves adapt to balance water loss, carbon dioxide absorption, and available light.
• The structure of leaves controls gas exchange and water loss.
• Leaves are fundamental units for constructing cones in gymnosperms and flowers in flowering plants.

Leaf Morphology

• A leaf consists of a petiole, lamina, stipules, and a sheath.
• Leaf characteristics like shape, margin, and hairs aid in plant identification.
• Leaves have determinate growth patterns.
• Leaf types can be monomorphic, dimorphic, or polymorphic.
• Deciduous plants shed leaves annually; evergreens retain leaves through winter.

Leaf Data Sources