What are the effects of light exposure on plants?

The effect of irradiation time on plants can be analyzed from two angles:

1) absolute time, that is when to illuminate. Artificial lighting is mostly in the evening activities, but as people, plants at night also need a dark environment, improper artificial lighting will disrupt the plant's light cycle thereby affecting its growth and development.

2 relative to, that is, as long as the light in the daytime is a natural phenomenon and has long been adapted to the plant, while the night long artificial lighting will disrupt the normal growth cycle of plants, and may even endanger life. For example, some plants undergo a period of low temperature treatment to complete the induction of flowers, and in some plants, he asked the length of day and night changes. Usually for plants that bloom in the spring, the sun must be long enough. For flowering plants in autumn, the sun must be short enough (dark enough to last).