Chloroplast movement provides photoprotection to plants by redistributing PSII damage within leaves.
Plants use light to fix carbon through the process of photosynthesis but light also causes photoinhibition, by damaging photosystem II (PSII). Plants can usually adjust their rate of PSII repair to equal the rate of damage, but under stress conditions or supersaturating light-intensities damage may exceed the rate of repair. Light-induced chloroplast movements are one of the many mechanisms plants have evolved to minimize photoinhibition. We found that chloroplast movements achieve a measure of photoprotection to PSII by altering the distribution of photoinhibition through depth in leaves. When chloroplasts are in the low-light accumulation arrangement a greater proportion of PSII damage occurs near the illuminated surface than for leaves where the chloroplasts are in the high-light avoidance arrangement. According to our findings chloroplast movements can increase the overall efficiency of leaf photosynthesis in at least two ways. The movements alter light profiles within leaves to maximize photosynthetic output and at the same time redistribute PSII damage throughout the leaf to reduce the amount of inhibition received by individual chloroplasts and prevent a decrease in photosynthetic potential.
Department of Biology, Indiana University, Bloomington, IN 47405, USA. phillipdavis2002@hotmail.com
Phillip A
PA
Davis
Roger P
RP
Hangarter
D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects*; D002734:Chlorophyll / Q000378:metabolism / Q000528:radiation effects; D002736:Chloroplasts / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects*; D008027:Light; D008034:Lincomycin / Q000494:pharmacology; D009154:Mutation; D010788:Photosynthesis; D045332:Photosystem II Protein Complex / Q000187:drug effects / Q000235:genetics / Q000528:radiation effects*; D018515:Plant Leaves / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology
D045332:Photosystem II Protein Complex; D011500:Protein Synthesis Inhibitors; D002734:Chlorophyll; D008034:Lincomycin