TERM PAPER - 2nd SEMESTER ROLE OF LIGHT QUALITY ON

PHOTOSYNTHESIS AND CHLOROPHYLL BIOGENESIS

SUBMITTED TO: SUBMITTED BY: MICROBIAL TECHNOLOGY DEPTT ADITYA SHARMA AMITY UNIVERSITY, NOIDA MSC (MT-3RD SEM) UTTAR PRADESH A0901209012

CONTENTS•INTRODUCTION TO LIGHT•PHOTOSYNTHESIS• CHLOROPHYLL AND ITS BIOGENESIS•EFFECT OF LIGHT ON PHOTOSYNTHESIS•PUBLISHED PAPER ON LIGHT QUALITY ON PHOTOSYNTHESIS.•PUBLISHED PAPERS ON EFFECT OF LIGHT QUALITY ON CHLOROPHYLL BIOGENESIS •REFRENCES

INTRODUCTION TO LIGHT

• Light is electromagnetic radiation of a wavelength that is visible to the human eye (in a range from about 400 nanometres to about 700 nm).

• Light has wave as well as particle properties.• Electromagnetic spectrum of light

• Important formula: E=hV

PHOTOSYNTHESIS

• Photosynthesis is a process that converts carbon dioxide into organic compounds, especially sugars, using the energy from sunlight and water from soil . Thus leading to production of carbohydrate and oxygen.

• Takes place in thylakoids,present in chloroplast in the mesophyll cells.

• 2 step mechanism: 1)light reaction 2)Dark reaction n CO2 +n(H2O) → (CH2O)N +nO2

MECHANISM OF PHOTOSYNTHESIS

CHLOROPHYLL

• Chlorophyll is a green pigment found in all plants, algae, and cyanobacteria.

• Chlorophyll molecules are specifically arranged in and around photosystems that are embedded in the thylakoid membranes of chloroplasts.

• The function of the vast majority of chlorophyll (up to several hundred molecules per photosystem) is to absorb light and transfer that light energy by energy transfer to a specific chlorophyll pair in the reaction center of the photosystems.

CHLOROPHYLL BIOGENESIS

• Aminolevulinic acid (ALA) is the precursor for all types of chlorophyll biosynthesis.

• In case of plants and animals ALA is made from glutamate this pathway is called C-5 pathway.

• In animals,yeast and purple bacteria the ALA is formed from glycine and succinyl CoA (Shemin pathway) .

• Structure of chlorophyll a.

EFFECT OF LIGHT ON PHOTOSYNTHESIS

• Light has 3 different effects on degree of photosynthesis : 1)Intensity of light- bright/dull light 2)Quality of light – PAR (400-700nm) 3)Duration of light – long/short

PAPER - 1

Effect of Light Quality on the Organization Of Photosynthetic Electron Transport Chain of Pea Seedlings

Received for publication June 25, 1976 and in revised form August 27, 1976NATALIA P. VOSKRESENSKAYA AND INNA S. DROZDOVAInstitute of Plant Physiology, Academy of Sciences ofthe USSR, Moscow 127106,

Botanicheskaya 35, USSRTATJANA E. KRENDELEVADepartment of Biology, Moscow State University, Moscow 117234, USSR

INTRODUCTION

• The activity of NADP and O2 photoreduction by water is essentially higher in chloroplasts isolated from pea seedlings (Pisum sativum L.) grown under blue light as compared with that from plants grown under red light.

• In contrast, the photoreduction of NADP and O2 with photosystem I only is practically the same or even lower in chloroplasts isolated from plants grown under blue light?

• NEED ?• It is becoming increasingly evident that in green plants, light not only

excites the energy-dependent reactions of photosynthesis, but it also serves in a regulatory capacity and controls essential mechanisms participating in the endogenous regulation of the vital activity of plants.

PROCEDURE

• Pea seedlings grown on vermiculate under red and blue light, light intensity kept equal accordingly.

• Prepration of chloroplast from leaves (15-20 days old).• Determination of activity of NADP reduction. -use of DPIP -Ferrodoxin and DCMU used -Note : NADP REDUCED WAS SAME IN BOTH CASES.• Determination of oxygen photoreduction. -using clark electrode.

COMPARISON

• The rate of NADP photoreduction by water is significantly higher in the blue chloroplast as compared with red.

• While NADP photoreduction by an artificial electron donor the activity in blue decreses by 2 units from red.while in case of red both the cases remain the same.

-hence difference between blue and red happens when water is electron donor.

• The endogenous O2 uptake excited by PS-2 is more in blue than red which ultimately proves electron transport from water driven by PS-2 is responsible for higher reduction of oxidants in blue chloroplast.

CONCLUSION

• Quality of light during growth of plants induces some alterations in ETC.

1)Increase in excitation enegy transfer from

chlorophyll to reaction centre of PS-2. 2)As well as same change in Electron transport chain organisation.

PAPER 2International Journal of Biotechnology and BiochemistryISSN 0973-2691 Volume 6 Number 4 (2010) pp. 521–536© Research India Publicationshttp://www.ripublication.com/ijbb.htm 

Effect of Light Quality on Chlorophyll Accumulationand Protein Expression in Wheat(Triticum aestivum L.) Seedlings Varsha Gupta1 and Baishnab C. Tripathy21Department of BiotechnologyChhatrapati Shahu Ji Maharaj University, Kalyanpur, Kanpur, U.P., IndiaE-mail: varsha5@yahoo.co.uk2School of Life Sciences, Jawaharlal Nehru University, New Delhi-110067, India

INTRODUCTION

• Quality and quantity of light defines growth of a plant.

• OBJECTIVE: To analyze growth of wheat seedlings in different light quality.

• NEED ?• WHEAT IS STAPLE FOOD in many parts of the

world.

PROCEDUREMEDIUM USED LGHT USED ABBRIVATION FOR 

LIGHT USEDRESULT (SEEDLING COLOUR)

WHITE GERMINATI--ON PAPER

RED LIGHT V- NON GREEN,NO Chl and carotenoids

VERMICULITE RED LIGHT V+ GREEN,Chl AND CAROTENOIDS

VERMICULITE FAR-RED FR GREEN, LOW Chl

VERMICULITE FAR-RED+RED FR+R GREEN,Chl and carotenoids

VERMICULITE/PAPE-R

WHITE LIGHT W GREEN,LOW CHLOROPHYLL

VERMICULITE DARK D GREEN,Chl PRESENT

VERMICULITE RED+BLUE R+B GREEN,Chl PRESENT

ANALYSIS SDS-PAGE and 2-D PAGE for protein analysis of all the protein

isolated in red light grown non green and green seedlings.• All the green plants grown under different light condition

showed steady protien expression in many cases.NOTE : these also acquired certain special special proteins which

were only present under certain light emission.

Western blot analysis of Cyt f,OEC-33,POR,and rubisco showed no presence in non green seedling,while showing different in abundance in green ones.

CONCLUSION

• Results show that light quality is a very important factor in influencing chlorophyll content as well as protein expression.

THUS AFFECTING PLANT GROWTH.

REFERENCES

FOR PAPER – 11. AKSYONOV, S. I., V. N. VERKHOTUROV, B. S. KAUROV, AND A. B. RUBIN. 1968. A

doublebeamspectrophotometer for recording difference spectra in photosynthesizing objects.Nauchni. doklady vys. shkoly. Biol. nauki 8: 123-128.2. ARNON, D. 1. 1949. Copper enzymes in isolated chloroplasts. Polyphenol oxidase in Betavulgaris. Plant Physiol. 24: 1-15.

FOR PAPER – 2[1] Beggs CJ, Wellman E. 1985 Analysis of light controlled anthocyaninformation in coleoptiles of Zea mays L. The role of UV-B, blue, red, and farredlight. Photochemistry and Photobiology41, 481-486.[2] Borthwick H, Hendricks S, Parker M, Toole E, Toole V. 1952. A reversiblephotoreaction controlling seed germination. Proceedings of the NationalAcademy of Sciences, USA 38, 662–666.

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