Bio group ppt plant tissue(1)

PLANT TISSUESBio-Group

Overview■ A. Plant tissues: meristematic and permanent■

‣B. Meristematic ‣ a. epical, ‣ b. vascular cambium‣ c. cork cambium

■‣C. Permanent tissues‣ a. parenchyma, ‣ b. collenchyma‣ c. schlerenchyma‣ d. chlorenchyma

■‣D. Complex permanent tissues‣ a. vascular, ‣ b. dermal‣ c. ground tissues

■‣E. Transpiration and capillary action.

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Meristematic and permanent tissues■ A meristem is the tissue in most plants containing undifferentiated cells

(meristematic cells), found in zones of the plant where growth can take place. Meristematic cells give rise to various organs of the plant and keep the plant growing.

■ Permanent tissues is the plant tissue that has completed its growth and differentiation and is usually incapable of meristematic activity.

Function■ Meristems are responsible for plant growth, regions where cells

continuously divide.■ Meristems are divided into apical, intercalary and lateral meristem.■ Apical and intercalary meristems are responsible for growth in length

(primary growth), while lateral meristem is responsible for growth in diameter (secondary growth)

Meristematic tissues:

Apical and Intercalary Meristem

■ Apical meristem is responsible for growth in length of most plants.■ It’s located at the tips of roots and stems of plants■ Some monocots (plants whose seeds contain one cotyledon) grow in

length via intercalary meristem.■ It’s located at the base of the stem of monocots, and appears as

nodes.■ It helps grass grow quickly after mowing.

Lateral Meristem

■ Gymnosperms (plants whose seeds aren’t protected by an ovary) and most dicots have lateral meristem

■ Lateral meristem increases the diameter of the plant’s stem and roots■ Lateral meristem has two types: vascular cambium and cork cambium■ Vascular cambium is located between xylem and phloem. It produces

more vascular tissue.■ Cork cambium is located outside the phloem, and it produces cork.■ Cork cells are dead cells that replace epidermis to provide protection

and prevent water loss

Permanent tissues:

These tissues derived from the meristematic tissues but their cells have lost the power of division & have attained their definite forms. Permanent tissues are classified into simple & complex tissues.

Permanent tissues are composed of cells which are structurally & functionally similar.

Simple Permanent tissues

Parenchyma

Schlerenchyma

Chlorenchyma

Collenchyma

aerenchyma

ParenchymaCharacteristic: cells remain alive at maturitythin-walled cellsisodiametric shape intercellular spaces widespread occurrence

in the plant body (leaves, root, stem)

Collenchyma

Characteristic: cells remain alive at

maturitycell walls are thickenedintercellular spaces absent

or very small Found in the peripheral

regions of stems and leaves

Sclerenchyma

■Characteristic: Mature sclerenchyma cells are dead Cells have thick secondary walls Found in shells and the outer hard

coat of many seeds

Summary

Chlorenchyma and aerenchyma ■ In leaves, they form the mesophyll and are responsible for

photosynthesis and the exchange of gases, parenchyma cells in the mesophyll of leaves are specialized parenchyma cells called chlorenchyma cells (parenchyma cells with chloroplasts)

Complex permanent tissues

Xylem Phloem

XylemNature-xylem is a vascular and composed of cells of four different types:

tracheids and vessels element (bounded by thick lignified. Vessels are very long tube-like structures formed by a row of cells placed end to end. They conduct water).

Functions-i. The main function of xylem is to carry water & minerals salts upward from

the root to different parts of shoots.ii. Since walls of tracheids, vessels of xylem are lignified, they give

mechanical strength to the plant body.

PhloemNature-Phloem is composed of following two types : 1.sieve tubes;2.companion cells; Functions-phloem transport photosynthetically prepared food materials from the leaves to the storage organs & later from storage organs to the growing regions of the plant body.

Dermal, Vascular and Ground tissues

How the plant transports water?

Transpiration and capillary action:Transpiration pulls water up a stem:

•the driving force of this process starts at the top of the shoot system

•transpiration occurs, loss of water lowers water potential between the cellulose fibers of the cell walls, and water quickly is replaced by capillary movement of water from neighboring cell walls, that also pull the water from other walls until the water is replaced by water from a xylem veinlet.

•as water is pulled out of xylem, the cohesion of water molecules pulls on the water in the xylem column like pulling of a rope, all the way to root cells which replace the water by absorbing it from the soil

Capillary action ■ Capillary action is part of the reason that water

rises in a plant stem and moves throughout the plant. The water enters the plant’s roots and moves to other parts of the plant through tiny tube-like structures called xylem. Xylem are part of the plants transpiration system, through which nutrients, including water, are transported throughout the plant.

1) The elongation of root and stem forms what is known as the......

A) initial plantB) protoplantC) primary plant bodyD) secondary growth

2) Internode elongation in corn results from the growth of....

A) intercalary meristemB) protodermC) procambiumD) cork cambium

3) The outward cell division of the root apical meristem produces the....

A) root hairsB) xylemC) branch rootsD) root capE) pith parenchyma

4) Which of the following is not a basic plant type?

A) pithB) ground tissueC) epidermisD) vascular tissueE) meristems

5) Gas exchange through the bark occurs through…..

A) stomataB) pitsC) lenticlesD) spiraclesE) micropyles

6) Mature sclerenchyma cells are……..

A) suberized and contain no living protoplastsB) thin walled and often contain chloroplastsC) lignified and contain living protoplastsD) suberized and contain living protoplastsE) lignified and contain no living protoplast

The EndThanks