Anatomy of stem,root and leaf of rice

Root TS

Epidermis Cortex Stele

Absence

Cuticle Stomata

Epidemal cell

Unicell. Root Hairs

Absorption Water/min.

Epidermis

SCLERENCHYMA

StrengthensRoot

Cortex Epidermis Stele

PARANCHYMATOUS

1. The cortex is poorly developed.2. Numerous air spaces 3. Aerenchyma in the cortical region 4. Gaseous exchange

• The centre region is occupied by vascular tissue forming stele.

• The vascular system is poorly developed• Root system poorly developed.

Absence

Sclerenchyma almost

cambium pith

Absence

Root Cap Root Hair

• A lot of air chambers present in root cells facilitate gaseous exchange when plant is submerged in anaerobic condition.

• Sclerenchyma below epidermis provide strength to root system

• A stem is one of two main structural axes of a vascular plant, the other being the root. The stem is normally divided into nodes and internodes.

• A stem develops buds and shoots and usually grows above the ground. Inside the stem, materials move up and down the tissues of the transport system.

The term "shoots" is often confused with "stems"; "shoots" generally refers to new fresh plant growth including both stems and other structures like leaves or flowers.

Transverse section of culm (stem 100×)showing epidermis (EP), vascular bundles (VB),ground tissue (GT) and central aerenchyma (ARC).

Stem TS

Epidermis Cortex Vascular tissue

Epidermis

Outermost

Protection

On outer cuticle Stomata Present

Gas. exchange

Cortex

Reduced

Narrow hypodermal region

Mature stems

Hypodermis is sclerenchymatic

Strength

Young stems

Chlorenchymatic patches

Below Stomata

Photosynthesis

Stele is the central part of the stem

Ground tissue

Shows air chambers.

Vascular bundlesCortex

Vascular bundles• Vascular bundles numerous

and scattered irregularly in the ground tissue.

• Peripheral bundles are small, closely arranged.

• Central bundles are large, widely arranged.

• Each vascular bundle is oval in shape.

• Surrounded by fibrous bundle sheath. • It is many celled thick towards outer and inner

regions • Few celled thick at lateral regions• Hence the vascular bundles are described as

fibrovascular bundles.• Vascular bundles are conjoint, collateral (with

xylem and phloem present on the same radius) and closed (i.e. without cambium).

• The xylem is present towards the centre of the axis and consists of few vessels which are arranged in the form of letter ‘Y’.

Phloem

Outside

Between metaxylem vessel

Consist of

Sieve tubes

Companion cells

Parenchymatous cells at the sides

• The stele consists of numerous vascular bundles scattered irregularly in the ground tissue, and is called an atactostele.

• It is the most advanced type of stele.

Significance of variations

• Rice stem is less defined in structure than in sorghum or wheat stem.

• Adapted well to anaerobic conditions.• Biotic and abiotic stress tolerance.• Since japonica rice has higher thickening of

sclerenchyma than indica rice, it is more tolerant to stem borers and desiccation

“A flattened structure of a higher plant, typically green and bladelike, that is attached to a stem directly or via a stalk. Designed by ALLAH for plant food manufacturing ”

• TS of leaf (100×) showing upper epidermis (UPEP), lower epidermis (LOEP),

• sclerenchyma patches (SCL), vascular bundles (VB),

• aerenchyma (ARC), parenchyma (PAR), mesophyll

• (MES) and brachisclereid (BRC).

Leaf TS

Epidermis Mesophyll V.B

Epidermis

Bullifrom Cells

Low water Level

Rolling Leaf

Uniseriate

More or less Oval

Rough cz of silica

crystals

Outer Wall

Cuticle

Graminaceous type of stomata

Less on Lower Epi.

2 Dumbell Shaped

Mesophyll

Spongy and Palisade

NotDifferntiated

Rolling Leaf

Composition

Lobed chlorenchyma

Length Breadth2:1

Aerenchyma

Cz Hydrophyte

• Papilla and trichomes cover the entire leaf surface except on the adaxial surface of the leaf sheath.

Phloem

Abaxial of bundle

Adexial

Poorly developed

Hydrophyte

Most, small size

Large occur

Regular interval

Leaf Anatomical Differences

• The 1st leaf lacks blade and is small in size compared to other leaves.

• The 5th and later leaves have a strong midrib, which providing mechanical strength.

• Leaves also differ in the capability of photosynthetic activities; early leaves are photosynthetically less efficient than later leaves.

(a) Transverse section of leaf (400×) showing the aerenchyma and vascular bundle; (b) vascular bundle (400×) showing proto- and metaxylem regions.

Rapid cell division

Shoot apical meristem

Sheath Elongation Starts

After Leaf bald’s

• Development of leaf blade and leaf sheath in rice is well coordinated.

• Air spaces known as lacuna are formed in the leaf sheath and midrib of the leaf blade.

ANATOMICALSIGNIFICANCE

Leaf Strength

Large Midrib

Phloem Well Than Xylem

Sclerenchyma Strands

Often Sclereids

High Photo. Capacity

Selection and Breeding

High mesophyll cell num.

Re-capture CO2 of

Photorespiration

Spatial arrangement

Chloroplast in Meso.

REFRENCES

Anatomy of stem,root and leaf of rice

vascular bundles cortex

numerous vascular bundles

vascular system

vascular bundles vb

root cells

stem ground tissue

vascular plants

root ts epidermis cortex

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