Abstract: The effects of different irradiance pre-treatments on leaf photosynthesis and low temperature ( 77K) chlorophyll
fluorescence (LTCF) parameters F685 , F735 , and F685􊄯F735 were observed in Arabidopsis, wheat , and soybean leaves
. The curve of photosynthetic responsing to irradiance transition from saturating to limiting one in Arabidopsis wild- type
leaves was the V pattern , while the curve in Arabidopsis mutant lacking chloroplast protein kinase STN7 was the L pattern .
Saturating white irradiation (SWI ) could induce the significantly decreased F685􊄯F735 without a significantly increased
F735 , while weak red irradiation (WRI) could lead to the significantly declined F685􊄯F735 with a significantly increased
F735 . The results showed that the attachment of dissociated LHC II to PS I in Arabidopsis wild-type leaves , indicating that
WRI can cause the transition from state 1 to sate 2 , while SWI can only induce LHC II dissociation from PSII reaction cen-ter complex . Moreover the results of LTCF analysis demonstrated that SWI could induce the LHC II dissociation in soybean
but not wheat leaves , while WRI could cause the state transition in wheat but not soybean leaves . Hence the LHC II dissociation
caused by SWI in Arabidopsis wild-type and soybean leaves was not a typical phenomenon of the state transition .

Key words: Arabidopsis