Plants available light focused on 400 ~ 460 nm blue-violet light district and 600 ~ 700 nm red-orange light district.
Blue-violet light (peak of 450nm) can improve the IAA oxidase activity, decreased levels of IAA, thereby inhibiting the elongation growth of plants, and has a fast response characteristics (can occur within a few minutes)but can also promote chloroplast movement, so phototropism more sensitive, but also to increase the content of plant protein.
Red-orange light (peak to 660nm) can enhance the ability of chlorophyll photosynthesis, and promoting plant growth and carbohydrate content increased, while the red light also reduces plants gibberellin (GA) levels, thereby reducing internode length and plant height.
Plants will be thin, slender or short,and stunted growth with in pure red or blue light irradiated,but the red and blue simultaneously irradiated plants are growing strong, so the two parts of red and blue light on the role of plants are complementary, with each other, are indispensable.