simple tissues

Botany anatomy

1. TOPIC SIMPLE TISSUES

2. “ A simple tissue is made up of similar type of cells which have common origin and function” DEFINITION OF SIMPLE TISSUES

3. Three types of simple tissues are Parenchyma Collenchyma sclerenchyma TYPES OF SIMPLE TISSUES

4. Parenchyma is a Greek word Para means “beside”& en means “to pour” parenchyma tissues is composed of living cells which are variable in their morphology & physiology 1. Parenchyma

5. It occurs in Pith Mesophyll of leaf Pulp of fruit Endosperm of seed Xylem and Phloem Occurrence

6. It consists of unspecialized cells with thin cell walls these are living, with a large central vacuole intercellular spaces between them. Oval ,rounded & polygonal in shapes Structure

7. Arenchyma In aquatic plants large air cavities are present which give buoyancy to the plants and help them to float Types of parenchyma tissues Chlorenchyma It contains chlorophyll & performs photosynthesis .

8. It provides support to plants and also stores food in the form of starch grains fats & oils Air spaces in parenchyma also facilitate exchange of gases Functions

9. They are elongated living cells with small intercellular spaces. Their cell walls are made of cellulose and pectin. It occur in the peripheral regions of stems and leaves. It allows easy bending in various parts of a plant (leaf, stem) without breaking. mature collenchyma are living & contain protoplast 2.collenchyma ( supporting tissues)

10. structure of collenchyma

11. Types of collenchyma tissues on the basis of cell arrangement three types are 1.Angular 2.Lamellar 3.tubular

12. 1. Angular In this type cells are irregularly arranged e.g ficus 2.Lamellar Cells are arranged in tagential rows(plate like arrangement) e.g sambucus 3. tubular Tube like arrangement, intercellular spaces are present

13. It provides mechanical support and flexibility in plants. Helps in photosynthesis Function of collenchyma

14. The sclerenchyma is a Greek word Sclerous means “hard” & enchyma means “ infusion” 3.Sclerenchyma

15. Sclerenchyma are long, dead cells with a deposit of lignin in their cell wall. They have no intercellular spaces. This tissue is present in stems, around vascular bundles, in the veins of leaves and in the hard covering of seeds and nuts. Thick walled cells Don’t possess living protoplast at maturity structure

16. It provides strength to the plant parts. it maintain the turgidity of plants function

17. Two types are Fibres Sclereides Types of sclerenchyma

18. elongated sclerenchyma cells,usually with pointed end The wall of fibres are usually lignified Pits of fibres are always small,round,or silt like At maturity the protoplast disappear & permanent cells becomes dead or empty It occurs in patches Average length of fibres is 1to 3mm 1.Fibres

19. Two types of fibres are Xylem fibres Extraxylary fibres Types of fibres

20. the fibres develop from the same maristematic tissues as the other xylem cells or The fibres which originated from xylem Xylem fibres

21. These are related to phloem that form continous cylinder in monocotyledon stem arise in the ground tissue under the epidermis at variable distance TYPES: 1.Phloem fibres (originating primary & secondary phloem) 2.Cortical fibres ( originating in the cortex) 3.Perivascular fibres ( originated in the peripheral region of vascular cylinder Extraxylary fibres

22. - Sclerenchymatous cells which are short and possess extremely thick, lamellated,  lignified  walls with long singular  piths . They are called sclerides Its is commonly found in cortex and pits of gymnosperms Types: 1.Brachysclereids 2.Macrosclereids 3.Osteosclereids sclereids

23. 4.Astrosclereids 1.brachysclereids stone cells are short & more or less isodiametric. These are commonly found in cortex ,phloem,& pulp of fruit 2.macrosclereids more or less rod like cells found in xerophytic leaves

24. 3.osteosclereids theses are bone shaped & found in the hypodermal layer of seeds & fruits 4.Asterosclereids these are star shaped found in intercellular spaces of the leaves & stem of hydrophytes