Light plays a crucial role in the lives of all organisms, affecting animal growth and the photosynthesis of plants. Only adequate light allows fruit tree seedlings to grow well. What are the impacts of light on fruit tree seedlings? Let's explain it for you.

Orchard seedlings are light-loving species, with light serving as the energy source for photosynthesis in the seedling leaves to produce organic matter. However, the utilization of light has a certain intensity range, typically represented by the light compensation point and the light saturation point. The light compensation point is the lower limit of light energy utilization, while the light saturation point is the upper limit. When the light intensity decreases to the point where the net photosynthetic rate of the leaves is zero, this light intensity value is called the light compensation point, which ranges from 600 to 1,000 lux. When the light intensity increases to a certain level, the net photosynthetic rate of the leaves no longer increases, at which point it reaches the light saturation point. For most apple orchards, the light saturation point ranges from 3,000 to 5,000 lux.

In regions with annual sunlight hours ranging from 2,200 to 2,800 and a sunlight rate during the growing season of 50 to 60 percent, it is suitable for the normal growth and development of fruit trees. In areas of China where annual sunlight hours exceed 2,500, the fruit quality is good. In regions with 2,000 to 2,500 hours of sunlight, the fruit quality is still relatively good. However, in areas with less than 1,500 hours of sunlight annually or where the monthly average sunlight during the growing season is less than 150 hours, the fruit quality is poor.

The development of red fruit color is greatly related to the quality of light. UV light can induce the production of ethylene in fruits and the synthesis of anthocyanins. Therefore, in areas with less smoke and dust, moderate humidity, and higher altitudes, fruit coloring is better. Most apple varieties require direct sunlight for fruit coloring, but diffused light can also be beneficial.