Photosynthetic Physiology of Blue, Green, and Red Light: Light Intensity Effects and Underlying Mechanisms

• DOI: 10.3389/fpls.2021.619987
• Publication Date: 2021-03-05T15:46:21Z
• Authors: Jun Liu; Marc W. van Iersel
• Keywords: Light intensity; Phytochrome

Red and blue light are traditionally believed to have a higher quantum yield of CO 2 assimilation ( QY , moles assimilated per mole photons) than green light, because is absorbed less efficiently. However, its lower absorptance, can penetrate deeper excite chlorophyll in leaves. We hypothesized that, at high photosynthetic photon flux density PPFD ), may achieve net rate A n ) red or more uniform absorption throughtout To test the interactive effects spectrum on photosynthesis, we measured leaf “Green Tower” lettuce Lactuca sativa under red, blue, combinations those s from 30 1,300 μmol⋅m –2 ⋅s –1 . The electron transport rates J maximum Rubisco carboxylation V c,max low (200 (1,000 were estimated response curves. Both m,inc (maximum incident basis) light. Factoring absorption, m,abs (the both indicating that was due while photons used inherently least At inc [gross g )/incident ] similar, confirming our hypothesis. not limit photosynthesis 200 μmol m largely unaffected by 1,000 different spectra positively correlated, suggesting effect between No interaction three colors detected. In summary, had lowest efficiency absorptance. Contrary, among highest, likely resulting distribution