Analysis of architectural parameters and solar radiation distribution in cucumber canopy in sunlight greenhouse

In order to study the relationship between plant canopy architecture and environmental elements in sunlight greenhouse, cucumber architectural parameters and the spatial distributions of global solar radiation in canopy were observed. The results showed that leaf area index, leaf area density, leaf zenith and azimuth angles varied obviously with growth stages and differed from varieties. Leaf area index increased steadily as the growth stages went on, and leaf area density increased at the early stage and decreased at the late stage. The height where much leaf area density was located was going up as cucumber developed; The main leaf zenith angle distributions were horizontal and the most leaf azimuth angles were leaning to the south. The differences were found to be related closely to spatial distributions of global solar radiation in canopy, also influencing photosynthetic rate. The results were anticipated to be useful in modeling the radiation transfer into cucumber canopy, developing the crop model, controlling greenhouse environment, reforming greenhouse architectural structure and so on.