Why should you avoid placing plants in direct sunlight?

Direct sunlight and high temperatures should be avoided as much as possible. This may sound contradictory, because light and heat are essential for the growth of plants, so-called photosynthesis. For an optimal growth there should be a good balance in climate between temperature, light and humidity. A plant in direct sunlight and high temperatures also need a high humidity, which is often lacking in room conditions. By this the photosynthesis process quickly decreases or stops altogether and heat becomes an important factor in leaf burn and premature ageing through accelerated bud and flower development and the tendency to drop leaves and flowers.