The intensity of PPFD affects the photosynthesis of plants within a certain range (below the light saturation point), the higher the PPFD, the higher the photosynthetic rate and the higher the plant yield.
Photocompensation point: The point at which the photosynthetic rate and respiration rate of a plant’s leaves are equal at a given light intensity.Photosynthetic rate and respiration rate are equal, and net photosynthetic rate is zero(formation and consumption of organic matter). (organic matter formation and consumption are equal), the light intensity at this time is called the light compensation point.
Light saturation point:After the light intensity has reached a certain value, the photosynthetic rate no longer increases when the light intensity is increased again, which is the light saturation phenomenon.
Light intensity design.
The role of PPFD values for plant growth is very important, and it is important not to
pay too much attention to the spectral/light quality design of plant light and neglect
Ignore light intensity design.
Light compensation point and light saturation point of representative plants
| Item | Plant species | Light compensation point （μmol/m²/s) | light saturation point (μmol/m²/s) |
| 1 | Tomatoes | 53.1 | 1985 |
| 2 | Cucumber | 51 | 1421 |
| 3 | Green pepper | 80 | 1719 |
| 4 | Eggplant | 50 | 1400 |
| 5 | Lettuce | 59.5 | 1320 |
| 6 | Strawberries | 43 | 320 |
| 7 | Grapes | 50 | 484 |
| 8 | Moonflower | 52 | 550 |
| 9 | Orchidaceae | 60 | 620 |
| 10 | Dendrobium | 80 | 325 |
| 11 | Succulent Sedum | 55 | 617 |
| 12 | Polyphyllaceae | 58 | 749 |
| 13 | Succulent Liliaceae | 50 | 523 |
| 14 | Acorus calamus | 57 | 424 |
| 15 | Cordyceps | 50 | 526 |
| 16 | Indoor Foliage Plants | 44 | 376 |
| 17 | Bowl of lilies | 55 | 657 |
| 18 | Ginseng | 49 | 506 |
| 19 | Cannabis | 63 | 780 |