Overview

This topic introduces the fundamental anatomy and physiology of plants. Understanding plant tissues, organs, and transport mechanisms is essential for grasping how plants grow, reproduce, and adapt to their environments.

Key Concepts and Structures

• Plant Tissues: Divided into dermal (outer protective layer), vascular (xylem and phloem), and ground tissue (photosynthesis, storage, and support).
• Roots: Anchor the plant and absorb water and minerals from the soil. Root hairs increase surface area for absorption.
• Stems: Support plant structure and transport fluids through vascular bundles. Contain nodes and internodes.
• Leaves: Main site of photosynthesis. Include structures like the cuticle, epidermis, mesophyll, veins, and stomata for gas exchange.
• Xylem: Conducts water and dissolved minerals upward from roots to shoots. Made of dead cells (tracheids and vessel elements).
• Phloem: Transports sugars and other organic nutrients from leaves to the rest of the plant. Composed of sieve tubes and companion cells.
• Transpiration: Loss of water vapor from leaves through stomata. Creates negative pressure that pulls water upward.
• Guard Cells: Specialized cells that open and close stomata to regulate gas exchange and water loss.
• Primary vs. Secondary Growth: Primary growth increases length (via apical meristems), while secondary growth increases thickness (via lateral meristems like vascular cambium).
• Plant Hormones: Chemical signals (e.g., auxins, gibberellins, cytokinins) that regulate growth, development, and responses to stimuli.

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