plant tissue

Plant Tissue Overview

Introduction

  • Understanding plant tissues is crucial for studying plant structure and function.

Objectives

  • Identify the types of plant tissues and their corresponding functions.

  • Know the importance of the different plant tissues.

  • Differentiate the types of plant tissues.

Types of Plant Tissues

1. Meristematic Tissue

  • Definition: Young actively dividing cells contributing to plant growth.

  • Function: Produces specialized cells that become permanent tissues.

2. Permanent Tissue

  • Definition: Cells that have specialized functions and have lost the ability to divide further.

  • Types:

    • Dermal Tissue

    • Ground Tissue

    • Vascular Tissue

Dermal Tissue

Functions

  • Covers and protects the plant.

  • Controls gas exchange and water absorption in roots.

Components

  • Cuticle: Waxy layer covering the epidermis to prevent water loss.

  • Epidermis: Outer protective layer of the primary plant body.

  • Stomata: Specialized pores for gas exchange (CO2 in, O2 out).

  • Root Hairs: Extensions that increase root surface area for nutrient absorption.

  • Trichomes: Hair-like structures that aid in defense against herbivores.

Ground Tissue

Overview

  • Comprises the bulk of the interior plant structure.

  • Involved in metabolic functions, food and water storage.

Types

  • Parenchyma: Living cells involved in photosynthesis and storage.

  • Collenchyma: Provides support in actively growing regions.

  • Sclerenchyma: Provides support in regions where growth has ceased.

Functions

  • Site of photosynthesis, supports vascular tissues, stores water and sugars.

Vascular Tissue

Overview

  • Responsible for the transport of water, minerals, and sugars throughout the plant.

Components

  • Xylem: Transports water and nutrients from roots to the rest of the plant; also provides support.

  • Phloem: Transports organic compounds from photosynthesis to different plant parts.

  • Vascular bundles always lie adjacent to one another.

Differences

  • Tracheids: Present in various vascular plants, narrow, less efficient water conduction.

  • Vessel Elements: Found only in angiosperms, wide, highly efficient in water conduction.

  • Sieve Tubes: Transport organic food; companion cells load/unload sugars into sieve tubes; present only in angiosperms.