Chlorophyll Fluorescence Characteristics of Phoebe zhennan Seedlings under Different Light Regimes
A study was performed to determine the daily changes of chlorophyll fluorescence parameters of Phoebe zhennan seedlings under different light regimes. Results show that the minimal fluorescence (F0), maximal fluorescence (Fm) , actual maximal fluorescence ( F1m ) , variable fluorescence (Fv) , optimal/maximal photochemical efficiency of PS II ( Fv/Fm), election transfer rate (Fm/F0) , and potential activity of PS II (Fv/F0) showed descending trends under 100% and 90% of light intensity between 8:00 and 18:00. However, these chlorophyll fluorescence parameters showed descending-ascending trends under 60%-65% and 50%-55% of light intensity between 8:00 and 18:00, and the lowest values occurred between 12:00 and 14:00. The non-photochemical quenching (NPQ) in 100% and 90% of light intensity showed ascending trends between 8:00 and 18:00. The NPQ in 60% -65% and 50% -55% of light intensity showed ascending-descending trends between 8:00 and 18:00, and the highest values occurred between 12:00 and 14:00. Results also showed that, except the significant differences (at the 0.05 level) in the average values of F0 and NPQ, there were no significant differences in other chlorophyll fluorescence parameters between 100% and 90% of light intensity. There were no significant differences in the average values of ail chlorophyll fluorescence parameters between 60% -65% and 50% -55% light intensity. The average values of F0, Fm, F'm, F,, Fv/Fm, Fm/F0, and Fv/F0 under 100% and 90% of light intensity, however, were significant (at the 0.01 level) lower than those under 60% -65% and 50% -55% of light intensity. On the contrary, the averages value of NPQ under 100% and 90% of light intensity were significant (at the 0.01 level) higher than those under 60% -65% and 50% -55% of light intensity, indicating that higher proportion of light energy absorbed by P. zhennan seedlings under 100% and 90% of light intensity was used for avoiding the destruction of photosynthetic tissue through heat dissipation.
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万方数据
维普
