An experiment was conducted to study the effects of drought stress on three main parameters of chlorophyll fluorescence in Toona sinensis potted seedlings from six provenances,including Nanjing of Jiangsu,Guangyuan of Sichuan,Dongkou of Hunan,Suizhou of Hubei,Xixia of Henan and Ankang of Shanxi. Results showed that the changing tendencies of the parameters were not completely identical. With the continuance of drought stress,the decreasing extent of Fv/Fm of T.sinensis leaves was very small for the six provenances. After rewatering,the other four provenances could almost recover to normal level except Dongkou of Hunan and Suizhou of Hubei. The photochemical quenching （qP） was heavily influenced by the prolonged drought stress. During the later stages of drought stress,the qP of Xixia of Henan and Ankang of Shanxi changed little,while the decreasing extent of qP of the other four provenances increased,especially for Dongkou of Hunan and Suizhou of Hubei provenances,but after rewatering,the two provenances could hardly recover. This indicated that the photochemical quenching of these two provenances was heavily influenced by drought stress. The non-photochemical quenching （qN） of all the six provenances increased to some extent in the initial and the later stages（except Guangyuan of Sichuan provenance） as well as after rewatering （except Suizhou of Hubei provenance）,which could avoid the harm of excess light energy to photosynthetic organs. But in the middle stage of drought stress,the qN of the six provenances decreased. The dynamic changes of the three main chlorophyll fluorescence parameters of six T.sinensis provenances were consistent with the level of drought resistance.
Journal of Northeast Forestry University
Chlorophyll fluorescence parameters