- Photosynthetically active radiation (PAR) had no significant directly influence to the Pn, but through other factors affect Pn indirectly.
- Wavelength-selective or photoselective mulches absorb photosynthetically active radiation （PAR） and transmit solar infrared radiation.
- The results showed that the percentage of photosynthetically active radiation (PAR) was about 80.1 in the absorption spectrum.
- The frequency of fog occurrence has been as high as 40% of annual time and has reduced ca. 70% of the accumulated photosynthetically active radiation.
- The transmittance of solar total radiation and the transmittance of photosynthetically active radiation (PAR) in a gable-type, single PVC covered greenhouse were studied.