Class 9 Bio Tissue Plant Tissue collenchyma sclerenchyma Xylem Phleum Vascular Bundle Explained

Class 9 Bio Tissue Plant Tissue collenchyma sclerenchyma Xylem Phleum Vascular Bundle Explained 🌱 Class 9 Biology – Plant Tissues (Explained) 🔹 What is Tissue? A tissue is a group of similar cells that work together to perform a specific function. In plants, tissues are divided into two main types: Meristematic Tissue – Actively dividing cells Permanent Tissue – Fully grown, non-dividing cells We’ll focus here on Permanent Tissues. 🌿 1. Permanent Tissue (Plant) These are tissues whose cells have lost the ability to divide and are specialized. ➤ Types: Simple Permanent Tissue (1 type of cells) Complex Permanent Tissue (more than 1 type of cell) 🔸 A. Simple Permanent Tissue ✅ i. Parenchyma Most common, soft tissue Living cells, thin-walled May have chloroplasts (if yes, called chlorenchyma) Stores food and helps in photosynthesis ✅ ii. Collenchyma 🟡 Living cells with unevenly thickened cell walls (mainly at corners) Provides flexibility and mechanical support Found in leaf stalks, stem of young plants 📌 Key Points: Elongated, living cells Cell walls thickened by pectin & cellulose Allows bending without breaking ✅ iii. Sclerenchyma 🟤 Dead cells with very thick and lignified walls No internal space Provides strength and stiffness 📌 Key Points: Found in seed coats, husk of coconut Two types: Fibres (elongated) & Sclereids (short, irregular) No nucleus or cytoplasm (dead cells) 🔸 B. Complex Permanent Tissue Made of more than one type of cell, working together. ✅ i. Xylem (Water Transport) Function: Transports water and minerals from roots to leaves 🔹 Xylem has 4 types of cells: Tracheids – Long, dead, tapered cells (water conduction) Vessels – Tube-like, dead, wider cells (main water transport) Xylem parenchyma – Living, stores food Xylem fibres – Dead, provides strength 📌 Xylem is a dead tissue (mostly) ✅ ii. Phloem (Food Transport) Function: Transports food from leaves to other parts of plant 🔹 Phloem has 4 types of cells: Sieve tubes – Long cells with perforated walls Companion cells – Control sieve tubes (living) Phloem parenchyma – Stores food Phloem fibres – Only dead component 📌 Phloem is mostly living tissue 🌿 2. Vascular Bundle ✅ What is it? A vascular bundle is the combination of xylem and phloem running together in the stem, root, or leaf. It forms the transport system of plants. Types of Vascular Bundles: Conjoint – Xylem and phloem together (as in stem) Radial – Xylem and phloem are separate (as in roots) Closed – No cambium (no secondary growth) Open – Has cambium (can grow laterally) 📊 Comparison Table Tissue Living/Dead Function Special Feature Collenchyma Living Flexibility, support Thick at corners Sclerenchyma Dead Strength Thick, lignified walls Xylem Mostly Dead Water and mineral transport Tracheids & vessels Phloem Mostly Living Food transport Sieve tubes + companion cells #class_9 #biology #concept #sikshaadhyayan #cell #cellstructure #cellmembrane #neet #olympiad #tripura #dharmanagar #sikshaadhyayan #shantanu_sir #ribosome #golgibody #ncert #cbseclass9 #tissue