Class 9th Science Tissues notes

These notes are strictly based on NCERT Class 9 Science, Chapter: Tissues, written in
simple exam-oriented language with full explanations, definitions, functions, types, and
examples.




PART 1: PLANT TISSUES
What is a Tissue?

A tissue is a group of similar cells that work together to perform a specific function.

Plants have tissues that are mainly responsible for growth, support, transport, and
protection.

Plant tissues are divided into two main types:

1. Meristematic Tissue
2. Permanent Tissue




1. MERISTEMATIC TISSUE
Definition

Meristematic tissue consists of actively dividing cells responsible for the growth of plants.

Characteristics of Meristematic Tissue

 Cells divide continuously
 Cells are small and thin-walled
 Dense cytoplasm
 Large nucleus
 Vacuoles absent or very small
 Cells are tightly packed (no intercellular spaces)

Types of Meristematic Tissue

(a) Apical Meristem

 Found at tips of roots and shoots
 Helps in increase in length of plant
 Responsible for primary growth

(b) Intercalary Meristem

 Found at the base of leaves or internodes

,  Common in grasses
 Helps in regrowth of grass after cutting

(c) Lateral Meristem

 Found along the sides of stems and roots
 Causes increase in thickness (girth)
 Responsible for secondary growth

Examples: Cambium, Cork cambium




2. PERMANENT TISSUE
Permanent tissues are formed from meristematic tissue when cells lose the power of
division.

Types of Permanent Tissue

1. Simple Permanent Tissue
2. Complex Permanent Tissue
3. Protective Tissue




A. SIMPLE PERMANENT TISSUE
1. Parenchyma

Characteristics

 Living cells
 Thin cell walls
 Large central vacuole
 Intercellular spaces present

Functions

 Storage of food and water
 Helps in photosynthesis (chlorenchyma)
 Provides support when turgid

Special Types

 Chlorenchyma: Contains chlorophyll, does photosynthesis
 Aerenchyma: Large air spaces, helps floating in aquatic plants