Lecture 2 - Plant Pigments | Plant Metabolism - Botany PDF Download

 Page 1


Plant Pigments 
 
Institute of Lifelong Learning, University of Delhi      
                                          1 
 
                                                                                                                                                      
 
 
 
 
 
 
 
 
Discipline: Botany 
Paper: Plant physiology 
Lesson: Plant Pigments 
Lesson Developer: Ms. Dhara Arora
 
Department/College: Department of Botany,  
University of Delhi
 
 
 
 
 
 
 
 
 
 
Page 2


Plant Pigments 
 
Institute of Lifelong Learning, University of Delhi      
                                          1 
 
                                                                                                                                                      
 
 
 
 
 
 
 
 
Discipline: Botany 
Paper: Plant physiology 
Lesson: Plant Pigments 
Lesson Developer: Ms. Dhara Arora
 
Department/College: Department of Botany,  
University of Delhi
 
 
 
 
 
 
 
 
 
 
Plant Pigments 
 
Institute of Lifelong Learning, University of Delhi      
                                          2 
 
 
Table of contents 
Lesson: Plant pigments 
? Introduction 
? Carotenoids 
? Flavonoid/ Anthocyanins 
? Chlorophylls 
? Betalains 
? Summary 
? Exercise/ Practice 
? Glossary 
? References/ Weblinks 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Page 3


Plant Pigments 
 
Institute of Lifelong Learning, University of Delhi      
                                          1 
 
                                                                                                                                                      
 
 
 
 
 
 
 
 
Discipline: Botany 
Paper: Plant physiology 
Lesson: Plant Pigments 
Lesson Developer: Ms. Dhara Arora
 
Department/College: Department of Botany,  
University of Delhi
 
 
 
 
 
 
 
 
 
 
Plant Pigments 
 
Institute of Lifelong Learning, University of Delhi      
                                          2 
 
 
Table of contents 
Lesson: Plant pigments 
? Introduction 
? Carotenoids 
? Flavonoid/ Anthocyanins 
? Chlorophylls 
? Betalains 
? Summary 
? Exercise/ Practice 
? Glossary 
? References/ Weblinks 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Plant Pigments 
 
Institute of Lifelong Learning, University of Delhi      
                                          3 
 
 
Learning outcomes: 
The student will be able to 
? Learn about the principal plant pigments 
? Learn about various kinds of pigments and their occurrence in plants  
? Understand Structures and biosynthetic pathway of carotenoids  
? Understand role of carotenoids present in plants 
? Understand types of flavonoids and their biological significance 
? Learn about anthocyanins and their uses 
? Understand the structure of chloroplasst  
? Understand the significant role of chlorophylls in photosynthesis  
? Explain the entire biosynthetic pathway of betalains 
? Learn about the properties and applications of betalains 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Page 4


Plant Pigments 
 
Institute of Lifelong Learning, University of Delhi      
                                          1 
 
                                                                                                                                                      
 
 
 
 
 
 
 
 
Discipline: Botany 
Paper: Plant physiology 
Lesson: Plant Pigments 
Lesson Developer: Ms. Dhara Arora
 
Department/College: Department of Botany,  
University of Delhi
 
 
 
 
 
 
 
 
 
 
Plant Pigments 
 
Institute of Lifelong Learning, University of Delhi      
                                          2 
 
 
Table of contents 
Lesson: Plant pigments 
? Introduction 
? Carotenoids 
? Flavonoid/ Anthocyanins 
? Chlorophylls 
? Betalains 
? Summary 
? Exercise/ Practice 
? Glossary 
? References/ Weblinks 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Plant Pigments 
 
Institute of Lifelong Learning, University of Delhi      
                                          3 
 
 
Learning outcomes: 
The student will be able to 
? Learn about the principal plant pigments 
? Learn about various kinds of pigments and their occurrence in plants  
? Understand Structures and biosynthetic pathway of carotenoids  
? Understand role of carotenoids present in plants 
? Understand types of flavonoids and their biological significance 
? Learn about anthocyanins and their uses 
? Understand the structure of chloroplasst  
? Understand the significant role of chlorophylls in photosynthesis  
? Explain the entire biosynthetic pathway of betalains 
? Learn about the properties and applications of betalains 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Plant Pigments 
 
Institute of Lifelong Learning, University of Delhi      
                                          4 
 
 
Introduction 
Pigments are the molecules which absorb light energy in the wavelength range 
of visible region. Upon absorption of light by a pigment molecule, the energy of 
absorbed photon is transferred to the electron. Chromophore (molecule-specific 
structure) captures the energy and excites the electron, due to which it jumps to 
a higher orbital. The non-absorbed energy is reflected and/or refracted back, 
captured by the eye and generates neural impulses, which are interpreted as 
color in the brain. The absorbed light can be used by the plant for chemical 
reactions. 
On the basis of origin, pigments can be classified as natural, synthetic, or 
inorganic. A variety of different kinds of molecules constitute the plant pigments 
such as, chlorophylls, flavonoids,  porphyrins, carotenoids, phycobilins, 
anthocyanins and betalains, etc. All biological pigments selectively absorb 
certain wavelengths of light while reflecting others. 
 
 
Page 5


Plant Pigments 
 
Institute of Lifelong Learning, University of Delhi      
                                          1 
 
                                                                                                                                                      
 
 
 
 
 
 
 
 
Discipline: Botany 
Paper: Plant physiology 
Lesson: Plant Pigments 
Lesson Developer: Ms. Dhara Arora
 
Department/College: Department of Botany,  
University of Delhi
 
 
 
 
 
 
 
 
 
 
Plant Pigments 
 
Institute of Lifelong Learning, University of Delhi      
                                          2 
 
 
Table of contents 
Lesson: Plant pigments 
? Introduction 
? Carotenoids 
? Flavonoid/ Anthocyanins 
? Chlorophylls 
? Betalains 
? Summary 
? Exercise/ Practice 
? Glossary 
? References/ Weblinks 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Plant Pigments 
 
Institute of Lifelong Learning, University of Delhi      
                                          3 
 
 
Learning outcomes: 
The student will be able to 
? Learn about the principal plant pigments 
? Learn about various kinds of pigments and their occurrence in plants  
? Understand Structures and biosynthetic pathway of carotenoids  
? Understand role of carotenoids present in plants 
? Understand types of flavonoids and their biological significance 
? Learn about anthocyanins and their uses 
? Understand the structure of chloroplasst  
? Understand the significant role of chlorophylls in photosynthesis  
? Explain the entire biosynthetic pathway of betalains 
? Learn about the properties and applications of betalains 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Plant Pigments 
 
Institute of Lifelong Learning, University of Delhi      
                                          4 
 
 
Introduction 
Pigments are the molecules which absorb light energy in the wavelength range 
of visible region. Upon absorption of light by a pigment molecule, the energy of 
absorbed photon is transferred to the electron. Chromophore (molecule-specific 
structure) captures the energy and excites the electron, due to which it jumps to 
a higher orbital. The non-absorbed energy is reflected and/or refracted back, 
captured by the eye and generates neural impulses, which are interpreted as 
color in the brain. The absorbed light can be used by the plant for chemical 
reactions. 
On the basis of origin, pigments can be classified as natural, synthetic, or 
inorganic. A variety of different kinds of molecules constitute the plant pigments 
such as, chlorophylls, flavonoids,  porphyrins, carotenoids, phycobilins, 
anthocyanins and betalains, etc. All biological pigments selectively absorb 
certain wavelengths of light while reflecting others. 
 
 
Plant Pigments 
 
Institute of Lifelong Learning, University of Delhi      
                                          5 
 
 
 
Figure: Some Major plant pigments 
 
Source:Author 
Some major plant pigments, their types and occurence 
Pigments Common types Occurrence color 
Chlorophylls Chlorophyll a, b Green plants Green 
Carotenoids 
Carotenes and 
xanthophylls 
Bacteria. Green plants 
(masked by chlorophyll), 
vegetables (carrots), fruits 
(mangoes). 
Orange, red, 
yellow, pink 
Flavonoids 
Anthocyanins, aurones, 
chalcones, flavonols and 
proanthocyanidins 
color production in flowers. 
Common in plants such as 
berries, citrus fruits, etc. 
Yellow, red, 
blue, purple 
Betalains 
Betacyanins and 
betaxanthins 
Flowers and fungi 
Red to violet, 
also yellow to 
orange