The researchers studied how two types of wheat plants cope with heat stress during grain filling by looking at their photosynthetic pigments and chlorophyll fluorescence. They found that under heat stress, one type of wheat had stronger photoprotective mechanisms than the other. The wheat plants showed changes in their photosynthetic pigments and chlorophyll fluorescence throughout the day, with some pigments playing a role in protecting the plants from too much sunlight. Overall, the study suggests that certain wheat plants have better ways to protect themselves from heat stress than others.