Photosystem II acclimation to limiting growth light in fully developed leaves of Amaranthus hypochondriacus L., an NAD-ME C4 plant.

A remarkable acclimation strategy was exhibited by Photosystem II when fully mature Amaranthus hypochondriacus L. plants grown at light sufficient (2000 μE m(-2) s(-1)) conditions were transferred to light limited environment (650 μE m(-2) s(-1)). There was a two pronged response of PS II to low growth light both by way of modulating the size of LHC II to offset the decrease in excitation energy capture and by decreased synthesis of reaction centre protein, D1 the later through depressed level of transcription of psbA gene. The molecular regulation of PS II under low light stress is discussed.