Plant Pigments and their role

Its all about pigments in plants Biological pigments, also known simply as pigments or biochromes are substances produced by living organisms that have a color resulting from selective color absorption. Biological pigments include plant pigments and flower pigments. Many biological structures, such as skin, eyes, fur and hair contain pigments such as melanin in specialized cells called chromatophores.
Pigment color differs from structural color in that it is the same for all viewing angles, whereas structural color is the result of selective reflection or iridescence, usually because of multilayer structures. For example, butterfly wings typically contain structural color, although many butterflies have cells that contain pigment as well.

1. Term Paper Presentation BTY 105: Principles of Biochemistry Topic: Plant Pigments and their role Submitted to: Dr. Kuldip Chandra Verma Deptt . Of Biotechnology Lovely Professional University Submitted by: Vir Sapan Pratap Anand 11202530 Section : B1205 Roll No. : A07

2. Introduction: What Are Pigments ? Pigments are “molecules that absorb specific wavelength (energies) of light and reflect all others.” Pigments are coloured . The colour we see is the net effect of all the light reflecting back at us…! They are the substances produced by living organisms that have a colour resulting from selective colour absorption.

3. What Do I Mean By “ Absorb” ? Electrons exist at specific levels Normally exist at lowest specific levels However, if enough energy comes to boost them into the next level, they can ABSORB that energy…!!! And occupy that higher level.

4. What Do I Mean By “Absorb” ? (Cont…) The light they absorb contains just the right amount of energy to push them into the next level. Light not having enough energy or having too much energy is reflected back…!!! Electron does not want to stay at higher level It wants to return because it is unstable there. Inorder to do this it has to release energy that has put it into higher level.

5. Ways to release energy ?? By heat: Conversion in molecular motion By fluorescence: Losing e- by light By Resonance: The energy but not the e- itself can be passed on to another molecule. By transferring the electron to another molecule - - - - - - - - - - - - - - - - - - - - - Plant pigments usually utilize the last two of these reactions to convert the sun’s energy into their own.

6. Biological Pigments Produced by living organisms. Have a colour resulting from selective colour absorption. Include “Plant pigments” and “Flower pigments.” Biological structures such as Skin Eyes Fur Hair Contain “melanin” pigment in specialized cells called “ chromatophores ”.

7. Pigment Colour V/s Structural Colour Pigments colour differs from structural colour . Pigment colour : “Same for all viewing angles”. Structural colour : “ Result of selective reflection or iridescence, usually because of multilayer structure. For example butterfly wings typically contain structural colour , although many butterflies have cells that contain pigment as well.

8. Types of Biological Pigments 1. Heme / Porphyrin based: Chlorophyll, bilirubin , hemoglobin , myoglobin . 2. Light Emitting: Luciferin 3. Carotenoids : Hematochromes : Algal pigments, mixes of carotenoids and their derivatives. Carotenes: alpha and beta Carotene Xanthophylls: Oxidised Carotenes ( Eg . Canthaxanthin ) 4. Proteinaceous : Phytochrome 5. Polyene enolates : A class of red pigments unique to parrots 6. Other: Melanin, Urochrome , flavanoids

9. Pigments in Plants-: The Principal pigments in plants are-: Chlorophyll Carotenoids Xanthophylls Anthocyanins Betalins

10. Primary Function of Pigments in plants:- Primary Function : Photosynthesis Uses green pigment chlorophyll along with several red and yellow pigments. Help to capture as much light as possible. Other functions include attracting insects to flowers to encourage pollination.

11. Chlorophyll Primary pigment in plant. Chlorin absorbs yellow and blue wavelengths. Reflecting green. All land plants and green algae have two types of chlorophyll. Chlorophyll a and Chlorophyll b. Kelps and photosynthetic heterokonts contain Chlorophyll c. Chlorophyll serve as fuel to photosynthesis.

12. Structure of Chlorophyll

13. More About Chlorophyll-: Name derived from greek words Chloros means “green” and phyllon means “leaf”. Synthesized from succinyl-CoA and Glycine . Immediate precursor to Chlorophyll A and B is protochlorophyllide . Contains hydrophobic phytol chain embedded in lipid membrane. Rest structure is tetrapyrrolic ring. It is the part of pigment that absorbs the energy from light.

14. CHLOROPHYLL and PHOTOSYNTHESIS Autotrophic Process: Plants and plant-like organisms make their energy (glucose) from sunlight. Stored as carbohydrate in their bodies. 6CO 2 + 6H 2 O + sunlight  C 6 H 12 O 6 + 6O 2 Makes organic molecules (glucose) out of inorganic materials (carbon dioxide and water). It begins all food chains/webs. Thus all life is supported by this process. It also makes oxygen gas!!

15. Why only Green and not Black ?? Black Colour is the best absorber of light. Then why couldn’t plants evolve this change ? Plants except some red algae appear brown or green but not black. Why ? If plants had pigments that absorbed UV and X-Rays, this would mean that electrons could be knocked off their orbitals and the molecule destroyed. If plants absorbed IR and Radio waves, there would not be enough energy for electron transfer, just enough to warm up the molecule.

16. Carotenoids : Red, orange or yellow pigments. Function as accessory pigments in plants. Absorb wavelength not readily absorbed by chlotophyll . Ex: Carotene ( Found in Carrots) Lutein ( Yellow pigment found in fruits and vegetables). Lycopene ( Red pigment in tomatoes)

17. Role of Carotenoids Attract pollinators and seed dispersers Accessory photosynthetic Pigment in periods of low light, Absorbs excess light energy, Anti oxidant roles, Substrate for hormones

18. Carotenoids : Carotenoids are Present in: Carrot, Sweet potato, Winter squash, Pumpkin, Green leafy vegetables, Cantaloupe, Apricot

19. Anthocyanins : Literally “Flower blue” Water soluble flavanoid pigments Colour appear as red to blue, acc to pH. Occur in all tissues of higher plants but colour not noticeable. Have purple colur and are present in: vegetables (onions, cabbage, potatoes), red, blue & purple berries, black beans

20. Role of Anthocyanins : attract pollinators and seed dispersers repel predators, protect cells from damage by excess light, improve plant tolerance to stress such as drought, U V-B, improve night vision and other vision disorders, protect against heart disease,

21. Betalins Red or yellow pigments. Water soluble. Synthesized from tyrosine. Never co-occur in plants having anthocyanins . Occur in: beets (red and yellow ), chard, spinach, fruit of prickly-pear cactus.

22. Role of Betalins Anti oxidant, May protect against heart disease, various cancers, ulcers, liver damage

23. Xanthophylls Fourth common class of pigments Essentially oxidized carotenes Usually red and yellow Do not absorb energy as well as carotenoids .

24. Conclusion: Life would be nothing without Plants… And Plants would be nothing without colours … Green plants having chlorophyll have a vital role in photosynthesis, a process neccessary for life on earth. Red and yellow plants and flowers having carotenoids or Betalins provide fresh fruits, and help in pollination. Blue plants and flowers having Anthocyanins are strong anti-oxidants.

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