Lecture 4 - General Anatomy of Leaf | Plant Anatomy - Biotechnology Engineering (BT) PDF Download

 Page 1


 
General Anatomy of Leaf 
Institute of Life Long Learning, University of Delhi 
 
0 
                                                                                              
 
 
Lesson Prepared Under MHRD project “National Mission 
on Education Through ICT” 
 
Discipline: Botany 
Paper: Plant Anatomy 
 
National Coordinator: Prof. S.C. Bhatla 
 
Lesson: General Anatomy of Leaf 
Lesson Developer: Dr Anita Rani, Dr Arun Kumar Maurya 
Department/College: Dyal Singh College 
 
 
Lesson Reviewer: Dr Basudha Sharma 
Department/College: MM (PG) College,Modinagar, Uttar Pradesh 
 
Language Editor: Dr Sonal Bhatnagar 
Department/College: Hindu College 
 
 
Lesson Editor: Dr Rama Sisodia, Fellow in Botany ILLL
Page 2


 
General Anatomy of Leaf 
Institute of Life Long Learning, University of Delhi 
 
0 
                                                                                              
 
 
Lesson Prepared Under MHRD project “National Mission 
on Education Through ICT” 
 
Discipline: Botany 
Paper: Plant Anatomy 
 
National Coordinator: Prof. S.C. Bhatla 
 
Lesson: General Anatomy of Leaf 
Lesson Developer: Dr Anita Rani, Dr Arun Kumar Maurya 
Department/College: Dyal Singh College 
 
 
Lesson Reviewer: Dr Basudha Sharma 
Department/College: MM (PG) College,Modinagar, Uttar Pradesh 
 
Language Editor: Dr Sonal Bhatnagar 
Department/College: Hindu College 
 
 
Lesson Editor: Dr Rama Sisodia, Fellow in Botany ILLL
 
General Anatomy of Leaf 
Institute of Life Long Learning, University of Delhi 
 
1 
Table of Contents  
Chapter: General Anatomy of Leaf 
 
? Introduction 
? General anatomy of leaf 
? Epidermis 
? Mesophyll 
? Veins (Vascular tissue) 
? Leaf development  
? Initiation 
? Early differentiation 
? Leaf axis development 
? Origin of lamina 
? Histogenesis of lamina 
? Development of veins 
? Genetic aspect of leaf development 
? Leaf arrangement 
? Alternate/ spiral  
? Distichous  
? Opposite  
? Decussate  
? Whorled  
 
? Types of leaves 
? Simple leaf 
? Compound leaf 
? Pinnate compound leaf 
? Palmate compound leaf 
Page 3


 
General Anatomy of Leaf 
Institute of Life Long Learning, University of Delhi 
 
0 
                                                                                              
 
 
Lesson Prepared Under MHRD project “National Mission 
on Education Through ICT” 
 
Discipline: Botany 
Paper: Plant Anatomy 
 
National Coordinator: Prof. S.C. Bhatla 
 
Lesson: General Anatomy of Leaf 
Lesson Developer: Dr Anita Rani, Dr Arun Kumar Maurya 
Department/College: Dyal Singh College 
 
 
Lesson Reviewer: Dr Basudha Sharma 
Department/College: MM (PG) College,Modinagar, Uttar Pradesh 
 
Language Editor: Dr Sonal Bhatnagar 
Department/College: Hindu College 
 
 
Lesson Editor: Dr Rama Sisodia, Fellow in Botany ILLL
 
General Anatomy of Leaf 
Institute of Life Long Learning, University of Delhi 
 
1 
Table of Contents  
Chapter: General Anatomy of Leaf 
 
? Introduction 
? General anatomy of leaf 
? Epidermis 
? Mesophyll 
? Veins (Vascular tissue) 
? Leaf development  
? Initiation 
? Early differentiation 
? Leaf axis development 
? Origin of lamina 
? Histogenesis of lamina 
? Development of veins 
? Genetic aspect of leaf development 
? Leaf arrangement 
? Alternate/ spiral  
? Distichous  
? Opposite  
? Decussate  
? Whorled  
 
? Types of leaves 
? Simple leaf 
? Compound leaf 
? Pinnate compound leaf 
? Palmate compound leaf 
 
General Anatomy of Leaf 
Institute of Life Long Learning, University of Delhi 
 
2 
? Modification of leaves 
? Leaf tendril 
? Leaf spine 
? Leaf pitcher 
? Leaf bladder 
? Leaf hooks 
? Phyllode 
? Fleshy leaves 
 
? Anatomy of dicot and monocot leaf 
? Dicot Leaf 
? Epidermis 
? Mesophyll 
? Conducting system 
? Monocot leaf 
? Epidermis 
? Mesophyll 
? Conducting system 
? Kranz Anatomy 
? Anatomy of Petiole 
? Summary 
? Glossary    
? Exercise 
? References 
Page 4


 
General Anatomy of Leaf 
Institute of Life Long Learning, University of Delhi 
 
0 
                                                                                              
 
 
Lesson Prepared Under MHRD project “National Mission 
on Education Through ICT” 
 
Discipline: Botany 
Paper: Plant Anatomy 
 
National Coordinator: Prof. S.C. Bhatla 
 
Lesson: General Anatomy of Leaf 
Lesson Developer: Dr Anita Rani, Dr Arun Kumar Maurya 
Department/College: Dyal Singh College 
 
 
Lesson Reviewer: Dr Basudha Sharma 
Department/College: MM (PG) College,Modinagar, Uttar Pradesh 
 
Language Editor: Dr Sonal Bhatnagar 
Department/College: Hindu College 
 
 
Lesson Editor: Dr Rama Sisodia, Fellow in Botany ILLL
 
General Anatomy of Leaf 
Institute of Life Long Learning, University of Delhi 
 
1 
Table of Contents  
Chapter: General Anatomy of Leaf 
 
? Introduction 
? General anatomy of leaf 
? Epidermis 
? Mesophyll 
? Veins (Vascular tissue) 
? Leaf development  
? Initiation 
? Early differentiation 
? Leaf axis development 
? Origin of lamina 
? Histogenesis of lamina 
? Development of veins 
? Genetic aspect of leaf development 
? Leaf arrangement 
? Alternate/ spiral  
? Distichous  
? Opposite  
? Decussate  
? Whorled  
 
? Types of leaves 
? Simple leaf 
? Compound leaf 
? Pinnate compound leaf 
? Palmate compound leaf 
 
General Anatomy of Leaf 
Institute of Life Long Learning, University of Delhi 
 
2 
? Modification of leaves 
? Leaf tendril 
? Leaf spine 
? Leaf pitcher 
? Leaf bladder 
? Leaf hooks 
? Phyllode 
? Fleshy leaves 
 
? Anatomy of dicot and monocot leaf 
? Dicot Leaf 
? Epidermis 
? Mesophyll 
? Conducting system 
? Monocot leaf 
? Epidermis 
? Mesophyll 
? Conducting system 
? Kranz Anatomy 
? Anatomy of Petiole 
? Summary 
? Glossary    
? Exercise 
? References 
 
General Anatomy of Leaf 
Institute of Life Long Learning, University of Delhi 
 
3 
Introduction 
Leaves are one of the most important organs of the plants. They are the prime source 
that provide green colour to our planet earth. They capture the light or solar energy and 
convert it into chemical energy with the help of chlorophyll molecules that are present in 
chloroplast, through the process known as photosynthesis. Leaves also help plants in 
water absorption by the process known as transpiration because of development of 
strong suction pressure in the cells of leaves that in turn helps in absorption of water 
from the roots and root hairs. In turn, leaves also act as conservator of water in plants 
by modifying them into spines (Opuntia), phylloclade and phyllode. The leaves modified 
into spines not only to prevent water loss but also act as a protective agent against 
herbivory.  
 
Figure: Leaves and their modifications: Opuntia A); Homalocladium platycladum – a 
phylloclade B); Acacia melanoxylon - phyllode C); Aloe and Bryophyllum - succulent 
plants (D-E); Macfadenya unguis-cati  with climbing hooks F); Lathyrus - tendrils G); 
Venus fly trap - insectivorous plants H) and Dischidia rafflesiana - pitcher I). 
Page 5


 
General Anatomy of Leaf 
Institute of Life Long Learning, University of Delhi 
 
0 
                                                                                              
 
 
Lesson Prepared Under MHRD project “National Mission 
on Education Through ICT” 
 
Discipline: Botany 
Paper: Plant Anatomy 
 
National Coordinator: Prof. S.C. Bhatla 
 
Lesson: General Anatomy of Leaf 
Lesson Developer: Dr Anita Rani, Dr Arun Kumar Maurya 
Department/College: Dyal Singh College 
 
 
Lesson Reviewer: Dr Basudha Sharma 
Department/College: MM (PG) College,Modinagar, Uttar Pradesh 
 
Language Editor: Dr Sonal Bhatnagar 
Department/College: Hindu College 
 
 
Lesson Editor: Dr Rama Sisodia, Fellow in Botany ILLL
 
General Anatomy of Leaf 
Institute of Life Long Learning, University of Delhi 
 
1 
Table of Contents  
Chapter: General Anatomy of Leaf 
 
? Introduction 
? General anatomy of leaf 
? Epidermis 
? Mesophyll 
? Veins (Vascular tissue) 
? Leaf development  
? Initiation 
? Early differentiation 
? Leaf axis development 
? Origin of lamina 
? Histogenesis of lamina 
? Development of veins 
? Genetic aspect of leaf development 
? Leaf arrangement 
? Alternate/ spiral  
? Distichous  
? Opposite  
? Decussate  
? Whorled  
 
? Types of leaves 
? Simple leaf 
? Compound leaf 
? Pinnate compound leaf 
? Palmate compound leaf 
 
General Anatomy of Leaf 
Institute of Life Long Learning, University of Delhi 
 
2 
? Modification of leaves 
? Leaf tendril 
? Leaf spine 
? Leaf pitcher 
? Leaf bladder 
? Leaf hooks 
? Phyllode 
? Fleshy leaves 
 
? Anatomy of dicot and monocot leaf 
? Dicot Leaf 
? Epidermis 
? Mesophyll 
? Conducting system 
? Monocot leaf 
? Epidermis 
? Mesophyll 
? Conducting system 
? Kranz Anatomy 
? Anatomy of Petiole 
? Summary 
? Glossary    
? Exercise 
? References 
 
General Anatomy of Leaf 
Institute of Life Long Learning, University of Delhi 
 
3 
Introduction 
Leaves are one of the most important organs of the plants. They are the prime source 
that provide green colour to our planet earth. They capture the light or solar energy and 
convert it into chemical energy with the help of chlorophyll molecules that are present in 
chloroplast, through the process known as photosynthesis. Leaves also help plants in 
water absorption by the process known as transpiration because of development of 
strong suction pressure in the cells of leaves that in turn helps in absorption of water 
from the roots and root hairs. In turn, leaves also act as conservator of water in plants 
by modifying them into spines (Opuntia), phylloclade and phyllode. The leaves modified 
into spines not only to prevent water loss but also act as a protective agent against 
herbivory.  
 
Figure: Leaves and their modifications: Opuntia A); Homalocladium platycladum – a 
phylloclade B); Acacia melanoxylon - phyllode C); Aloe and Bryophyllum - succulent 
plants (D-E); Macfadenya unguis-cati  with climbing hooks F); Lathyrus - tendrils G); 
Venus fly trap - insectivorous plants H) and Dischidia rafflesiana - pitcher I). 
 
General Anatomy of Leaf 
Institute of Life Long Learning, University of Delhi 
 
4 
A) http://en.wikipedia.org/wiki/Opuntia 
B) http://commons.wikimedia.org/wiki/File:Homalocladium_platycladum_13.jpg 
C) http://davesgarden.com/guides/pf/showimage/93465/ 
D) http://www.safeandhealthylife.com/aloe-vera-natures-precious-gift-to-life; 
E) http://karnak.wikispaces.com/Herbal+Remedies 
F) http://herbaria.plants.ox.ac.uk/vfh/image/index.php?item=186 
G) http://www.colourbox.com/image/close-up-tendrils-of-pea-image-2151234 
H) http://www.darwinproject.ac.uk/insectivorous-plants; 
I) http://toptropicals.com/catalog/uid/Dischidia_rafflesiana.htm 
 
Leaves act as a store house of minerals and food material as found in succulent plants 
(Aloe and Bryophyllum). Leaves act as climbing agent by forming hooks (Macfadina 
unguis-cati) and tendrils (Lathyrus). Leaves in carnivorous or insectivorous plants are 
partially or wholly modified into pitcher like structures which trap insect. In epiphytic 
climber, Dischidia rafflesiana the pitcher not only traps insects but also helps in storage 
of water. Leaves act as major nutrient cycler in ecosystem operating with temporal 
adjustment at different regions. In temperate regions, deciduous plants typically shed 
their leaves in autumn whereas in regions with a severe dry season, plants may shed 
their leaves at the end of the dry season. In both the cases, the shed leaves contribute 
to the nutrients of the soil. Thus, the leaf performs diverse function and proves its 
importance. 
In contrast, many other non-seasonal plants, such as palms and conifers, retain their 
leaves for longer period of time; Welwitschia mirabilis, a monotypic genus found in 
Namib dessert of Namibia and Angola retains its two main leaves throughout its lifetime 
(approximately 1000 year or more). Many plants do not have true leaves for e.g. non-
vascular plants such as mosses and liverworts. They produce flattened, leaf-like 
structures which are green due to presence of chlorophyll, but these organs differ 
morphologically from the leaves of vascular plants. 
A typical foliage leaf of an angiosperm consists of a leaf base, petiole (leaf stalk), a 
lamina (leaf blade) and stipules (small structure located to either side of petiole base. 
Petiole forms a connection between leaf to stem or branches and aids in the 
transportation of water and sugar assimilates. These structures are not necessarily found 
in all plants species. The petiole or stipules are either not distinct or absent altogether, or 
the blade may not be laminar (flattened).