Effects of Heat Stress on Photosynthesis and Chlorophyll Fluorescence Parameters in Tomato Seedlings

Heat-tolerant tomato accession Saladette was used to analysis assimilation product distribution,photosynthesis and chlorophyll fluorescence parameters.The results showed that under the high temperature treatment,the plant height and expansion were increased,however,fresh and dry weight of shoot and root were less than those of the control,and the photosynthetic rate of tomato leaves was suppressed as well.With the extension of processing time,photosynthetic rate decreased by 31.65%,23.57%,22.71% and 14.5% respectively.Regulated energy dissipation of the quantum yield Y(NPQ) increased by 144%,but non-regulated energy dissipation of the quantum yield Y(NO) had little change.The increment of Y(NPQ) of leaves can protect photosynthetic apparatus against high temperature.