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Organ is a composition of tissues doing

particular function together. Main plant organs that

have vegetative characteristics consist of root (radix),

stem (caulis), and leaf (folium).

1. RootRoot is a plant organ that anchors into

the soil. The function is to absorb water and

mineral salts from the soil, strengthen the plant

erection, store food, and as respiratory organ,

e.g. mangrove root.

In root anatomy, the orderly structure

from outward to inward is epidermis, cortex,

endodermis, and vascular cylinder.

a. EpidermisThe epidermis of root consists of

a single layer cell that is tighly packed

without intercellular air space. The

walls are thin and semi permeable. The

presence of epidermal cell behind the

growth point of root causes the root

surface larger; therefore the substance

absorption becomes more efficient.

b. CortexCortex of root consists of

multiple layers of cells with thin walls.

The cells are loosely arranged so they

have many intercellular spaces. The

cells often contain starch as food

storage or even crystal.

Competency standard :

To know relationship between

structure and function of plant tissue

and it applying in environmental

science of society and technology

context

Basic competency:

To identified structure function of

plant and correlating it with it

function, to explain totipotency

character as tissue culture basic

Indicator:

y To make plant organ microscopicobservation preserve

y To observe structure of plantorgan

Main matter:

Observation structure of tissues of

plant organ

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c. EndodermisEndodermis consists of one layer cell that is tightly packed

without intercellular air space, located in the innermost layer of cortex.

Young cells of endodermis have thin and semi permeable walls.

d. Stele (VascularCylinder)Stele is located in the innermost of endodermis. It consists of

several tissues, as follows.

y Pericycle (pericambium), which is the outer layer of stele.y Vascular bundle, which consists of xylem andphloem on alternating

radii.

y Pith, which is the tissue between vascular bundle that consists ofparenchyma tissues.

2. StemStem is a plant organ which grows on ground surface. The functions

are to conduct water and mineral salts from root to leaves, to conduct nutrition

from leaves throughout plant body, as a place to store food, and as the

attachment site of leaves, flowers, and fruits.a. Dicotyledon Stem

Dicotyledon stem grows from apical meristem which makes the

stem always elongate. The part of the apical meristem is called growth

point. The tissues that compose dicotyledon stem, from the epidermis

inward are: epidermis, cortex, endodermis, pith, cambium, phloem,

xylem, and pith rays.

b. Monocotyledon StemMonocotyledon stem has small apical meristem and consists of

epidermis, ground meristem, and vascular bundle. Monocotyledon has

scattered vascular bundle on the ground meristem and closed collateral

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type. Each vascular bundle is surrounded by bundle sheath (sclerenchyma

bundle) which is usually thick, particularly onthe sheath edge.

3. LeafLeaf has several functions, such as a place for photosynthesis, to

absorb CO2 from environment, and to discharge excessive water. Leaf

consists of some tissues, dermal tissue (epidermis), ground tissue (mesophyll),

and vascular tissue.

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1.2 Activity

A. Purpose : Observing the tissues of plant organ (stem).B. Tools and Materials

1. a microscope2. some object glasses3. some cover glasses4. a razor5. a piece of blotting paper6. some aniline sulfate solution 1%7. a slice of stem of corn (Zea mays) and peanut (Arachis hypogea)

C. Procedures:1. Make cross section on stem available plant by using a razor. Try to cut as

thin as possible.

2. Put the section on different object glass that has been dropped by anilinesulfate.

3. Cover the object glass with the cover glass.4. Observe the specimens that you have made by using the microscope with

magnification start from 10 x 10, then with larger magnification.

5. Draw the observed parts and give explanation.Questions:

1. What are the differences between the structure of stem of corn (Zea mays)and that of peanut (Arachis hypogea)?

2. On what magnification can the tissue specimens be clearly observed?