Influence of Drought Stress on Chlorophyll Fluorescence in Ramie [Boehmeria Nivea(L.) Gaud.]

Ramie Chuanzhu 11was planted in pots which were set 4 treatments( namely well-watered,mildly-watered,moderate and severe drought stress) for 18 days in a rain-proof house.Then chlorophyll fluorescence traits were assessed.The results showed that drought stress caused a substantial decrease in the maximum quantum efficiency of PSII photochemistry( Fv / Fm),quantum efficiency of open PSII reaction centers( F'v / F'm),quantum yield of PSII( φPSII),photochemical quenching( qP) and electron transport rate of PSII( ETR) while non-photochemical quenching( NPQ) changed in opposite direction.Nonetheless,these changes were closely related with the intensity of the drought stress.Mild drought stress led to no significant change while moderate and severe drought stress caused significant alteration in the chlorophyll fluorescence characteristics,suggesting that ramie could withstand mild drought stress( ρ 0.05).Therefore,when the field soil is under a moderate drought condition,mitigation measures must be timely taken in order to ensure the normal growth of the plants.