The rate of photosynthesis increases with the increase in temperature, only upto a certain limit. For every 10° rise, the rate is almost doubled. The plants show maximum photosynthesis at optimum temperature. It is between 20-30° C. Further increase in temperature leads to decrease in the rate of photosynthesis as the enzymes get denatured at high temperature and do not work efficiently.
Figure : Effect of temperature on photosynthesis.