The Sun

The light can damage pigments and the heat can disrupt the biochemistry of the plant cells. Intense heat can cause evaporation of water in the plant to quicken. Then, the plant will die even faster.

To survive, each plant must have some way to protect itself from the rays of the sun. Some have a thick waxy coating to protect itself, like the cacti. And some hide behind in the shade. Some others shed their leaves when it is slightly hotter.