1. The shade avoidance effect of 730nm far red light.
If the plant is only exposed to the dark red light of 660nm, the plant will feel that it is under direct sunlight and thus grow normally. If the plant is mainly exposed to the far red light of the 730nm, the plant will feel as if it is being obscured by another taller plant, so the plant will grow harder to break through the barrier, which helps the plant grow taller, but does not necessarily mean that there will be more biomass (bio mass).
2. Flowering induction of far red light at 730 nm.
Another important role of 730nm far red light in horticultural lighting is that the flowering cycle can be controlled by the lighting of 660nm and 730nm, rather than relying only on the influence of season, which is of great value for ornamental flowers.
The conversion of photosensitive pigment Pr to Pfr is mainly induced by the dark red light of 660nm (representing daytime sunlight), while the conversion of Pfr to Pr usually occurs naturally at night, and can also be excited by 730nm far red light.
It is generally believed that the control of plant flowering by photosensitive pigments mainly depends on the ratio of Pfr/Pr, so we can control the Pfr/ pr value by far red light irradiation of 730 nm, so as to control the flowering cycle more accurately.
3. Customized light formula for LED grow light
LED is used for horticultural lighting, which can promote plant growth by up to 40% or flexibly control flowering. Since a single LED is independent of each other, the lighting performance can be easily controlled in the greenhouse.
The photosynthetic photon flux (Photosynthetic Photon Flux,PPF) light efficiency of LED itself is very high, the typical PPF light effect of dark blue (450nm) and far red (730nm) light LED is about 2.3?mol/J, and the typical PPF light effect of super red (660nm) LED is about 3.1?mol/J. In addition, the wavelengths of these LED are very consistent with the absorption spectra of chlorophyll a, carotenoid and photosensitive pigment Pr/Pfr. It can achieve efficient lighting and significantly reduce energy consumption.
LED does not emit heat in the direction of lighting and does not damage plants. It is suitable for top lighting, internal lighting and multi-layer cultivation. The R/FR ratio is the ratio of the intensity of red light (660 nm) to that of far red light (730 nm). R / B ratio is the ratio of red light (660 nm) to blue light (450nm). The best customized light formula for all kinds of plants can be realized by controlling the R/FR ratio and RhampB ratio.