heliosis

from The Century Dictionary.

• noun In botany, the production of burned patches or spots on leaves by the concentration of the rays of the sun through inequalities of the glass of conservatories, or through drops of water resting on the leaves.
• noun In medicine: Treatment of disease in certain cases by exposure to the rays of the sun.
• noun Sunstroke.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun Sunstroke
• noun Exposure to the sun
• noun Scorching of plants by the sun