| Abstract:In order to understand effects of low temperature on photosynthesis of Viola×wittrockiana and Viola cornuta,and provide reference for cultivation and breeding under environment of low temperature ,an experiment was conducted with a Viola×wittrockiana germplasm,named HAR,and three Viola cornuta germplasm,named JB,E01 and 08H.The photosynthetic and chlorophyll fluorescence parameters of 4 pansies were measured after the plants treated under five low temperature conditions,namely,-5 ℃ for 8 h,16 h and 24 h,-10 ℃ for 7 h and 14 h.The results showed that under low temperature stress,the net photosynthetic rate(Pn),stomatal conductance(Gs),transpiration rate(Tr),Fv/Fm,photochemical quenching coefficient(qP) and actual photochemistry(ΦPSⅡ) of pansies decreased with the increace of low temperature stress,while the intercellular CO2 concentration(Ci),initial fluorescence(F0) and non photochemical quenching coefficient(qn) increased.The degree of change was different among four genotypes.According to changes of photosynthetic and chlorophyll fluorescence parameters of the tested materials,we found that E01 and JB had stronger cold tolerance,the next one was 08H,while the cold tolerance of HAR was poor relatively. |
