Effects of low temperature stress on chlorophyll fluorescence characteristics and excitation energy dissipation in eggplant seedling leaves

Effects of low temperature stress on chlorophyll fluorescence of eggplant(Solanum melongena L.)seedlings were investigated in this experiment.Results indicated that,as the treatment temperature decrease,several parameters including maximum fluorescence(Fm),photochemical maximum efficiency of PSII(Fv/Fm),potential photochemical efficiency(Fv/Fo),the electron transport rate(ETR),actual photochemical efficiency of PSII(ΦPSII),photochemical quenching coefficient(qP),were decreased,and the ration of absorbed light in photochemistry(P)was also decreased. At the same time,minimal fluorescence(Fo),non-photochemical quenching coefficient(qN)were increased,and the ratio of thermal dissipation(D)and excess energy(E)were also increased.The response curve ofΦPSII to light intensi- ty demostrated when light intensity increased,ΦPSII responded in a quick decline way.Response curve of ETR to light intensity showed lower saturate electron transport rate and lower light saturation point on eggplant seedlings with low tem- perature stress.Results suggested that reaction center of PSII was damaged,and pathways of photosynthetic electron transport were inhibited in eggplant seedlings when exposed to the low temperature stress.