There are two main effects of light on plants: First light is the necessary conditions for photosynthesis of green plants; Then, light can regulates the whole growth and development of plants. Plants make organic matter and release oxygen by absorbing light energy, assimilating carbon dioxide and water. The growth and development of plants rely on photosynthesis to provide the necessary organic material. In addition, light can inhibit the longitudinal elongation of plant cells, make plants grow robust, control the plant growth, development and differentiation known as light shaping. Light quality, illumination and period are all closely related to the growth and development of medicinal plants, which affect the quality and yield of medicinal materials.
The Effect of light intensity on growth and development of medicinal plants
The photosynthetic rate of plants increases with the increase of illumination, and within a certain range they are almost positively correlated, but the rate will become slow after a certain range.When reaching a certain illumination, the rate will be no longer increases, this phenomenon is called light saturation phenomenon, the illumination at this moment is called light saturation point. When the light is strong, the photosynthetic rate is several times larger than the respiration rate. But with the decrease of the illumination, the photosynthetic rate will gradually approaches the respiration rate, and finally reaches the point equal to the respiration rate. At this moment, the illumination is called the light compensation point. Different plants have different light saturation point and light compensation point. According to the different needs of light illumination, they are usually divided into Sun plants, Shade plants and Intermediate plants:
1) Sun plants (light-loving or sun-loving plants). Grow in direct sunlight. The light saturation point was 100% of total illumination, and the light compensation point was 3% ~ 5% of total illumination. Without enough sunlight, the plant can not grow well and with the low yield. Such as hemp, tomato, cucumber, lettuce, sunflower, chrysanthemum, peony, yam, wolfberry and so on. When growing these types of plants in low-light areas, Growook’s LED Growpower can be used to fill-in light to increase yield.
2) Shade plants (shade-loving or shade plants). Usually they can not bear the intense sunlight and like to grow in the dank environment or under the forest. The light saturation point is 10% ~ 50% of the total illumination, and the light compensation point is less than 1% of the total illumination. Such as ginseng, American ginseng, panax notoginseng, dendrobium, rhizoma.
3) Intermediate plant (shade tolerant plant).Plants which between the sun plant and shade plant. They can grow well in this two environments. For example, Ophiopogon japonicus, cardamom, Nutmeg, coltsfoot, lettuce, Viola philippica and Bupleurum longiradiatum Turcz, etc.
Under natural conditions, when plants grow and develop, the more light they receive around the light saturation point (or slightly higher than the light saturation point) with the longer time, the more photosynthetic accumulation, and the best growth and development.General speaking light illumination is lower than light saturation point, it is called the illumination is insufficient. The illumination is slightly higher than the compensation point, although the plant can grow and develop, but the yield is low, the quality is not good. If the illuminance is lower than the light compensation point, the plant will consumes nutrients instead of producing them. So in order to increase the yield, use Growook’s LED Growpower to increase the intensity and duration of light.