Insufficient sunshine in winter mainly affects the growth of fruit trees in greenhouse, but has little effect on deciduous fruit trees in the north cultivated in the open field, and has great influence on evergreen fruit trees.

Northern deciduous fruit trees cultivated in the open field are dormant in winter, so the requirements for light are not strict, and the length and intensity of sunlight have little effect on them. The influence of the length and intensity of sunshine in winter on evergreen fruit trees in the south is much greater than that of deciduous fruit trees in the north, and there is no detailed data at present.

The length and intensity of sunshine in winter have the greatest influence on the fruit trees cultivated in protected areas. The length and intensity of sunshine in winter and spring will have a great influence on the growth and development of fruit trees in greenhouse. The length of sunshine and the intensity of light will not only directly affect the rate of photosynthesis, but also affect the temperature in the greenhouse, so the impact on fruit trees in the greenhouse is very great. Generally speaking, under the conditions of long sunshine time and sufficient sunshine, plants grow sturdily, have strong disease resistance, high fruit yield and good quality; On the contrary, it will lead to low fruit yield and poor quality. Therefore, in winter, when cultivating fruit trees in greenhouse, we should try our best to extend the illumination time and improve the illumination intensity.