STUDIES ON KINETICS AND THERMODYNAMICS OF EFFECTS OF PRIMARY COLOURS ON PHOTOCHEMICAL REACTIONS: PHOTOSYNTHESIS IN Loudetia arundinacea IN FOCUS

Abstract

Light, especially green light in sunlight, is reflected alongside absorption of other wavelengths of electromagnetic radiation by leaf before photosynthesis can take place, with no application of extra external energy and without pollutants. Green being one of the primary colours of white light makes the investigation of effect of irradiation of elephant grass (Loudetia arundinacea) with primary colours. Duration of irradiation with LEDs and sunlight ranged from 300s to 1800s, at 300k. Primary colours were absorbed with 0.01M KMnO4, 0.01M methyl orange 1M CuSO4 and 1M NiSO4. Total carbohydrate formed by L .arundinacea after irradiation obtained using anthrone test became a measure of photosynthesis. Rate of photosynthesis in 30 minutes in L. arundinacea decreased in the order; BLED>WLED>GLED>RLED; also, W-b>W-g>W-br>W-r; and S-b>S-br>S>S-g>S-r. While BLED with TCPR of 15.62±0.001mg/100mg, is most favorable to photosynthesis, W-b had its TCPR reduced to 8.85±0.001mg/100mg, and W-r, as well as S-r had their TCPR as 1.91±0.001 and 5.09±0.001mg/100mg respectively, being higher than pure RLED with 0.26±0.001mg/100mg. Influence of green light over red light in W-b causes higher TCPR than when red light combines with blue light in W-g. Passage of other waves of electromagnetic spectrum causes elevated TCPR for S-b, S-br and S-r compared to those for W-b, W-br and W-r.