Anatomy of stem,root and leaf of rice
Nov 17, 2014
Described in a beautiful manner using smart art and bullets.
Adeel Anjum Ishtiaq ShariqAsad Ullah KhanM.Faizan Ahmad
Roll # 1Roll # 2Roll # 3Roll # 4
GROUP # 1Including
• Rice is an herb having a plant height of 2–4m. The plant generally takes 3–6 months to complete its life cycle.
• Second most important crop after wheat.• Consumed by more than 75% of world
population.• Annual grass.• Genus Oryza ,more than 20 wild species and
two cultivated diploid species (2n = 2x = 24)• Cultivated since 2000 B.C.
Anatomy
Greek word “anatomia” To dissect and See
“Anatomy is a branch of biologicalscience concerned with the study of the
internal structure of body parts of an organism.”
• In vascular plants, the root is the organ of plant that typically lies below the
surface of the soil.
Transverse section of root (100×)illustrating epidermis (EP), sclerenchymatichypodermis (HYP), cortex (COR), aerenchyma(ARC), endodermis (END), pericycle (PC), xylem (X),phloem (PHL) and medulla (MED).
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.
• 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).
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.
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).
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.
V.B
Phloem
Abaxial of bundle
Xylem
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.
Leaf
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.
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.
