The relationship between light transmittance and canopy structure parameters of nectarine trees in Chinese lean-to greenhouse.

摘要

Canopy structure plays an important role in affecting canopy light environment. The canopy structure parameters (including LAI, canopy thickness, canopy openness and canopy gap characters), associated with canopy light transmittance, were observed in 5-year-old 'Ruiguang 5' nectarine trees inside Chinese lean-to greenhouse. All the canopies were divided into three regions, i.e. northern region, middle region and southern region. The results showed that during stage I of fruit growth canopy light transmittance decreased exponentially with the development of LAI. During stage III, the light transmittance of canopy was affected most strongly by canopy thickness in northern and southern region and by canopy openness in middle region. The relative light intensity decreased most rapidly before sunlight reached a canopy depth of 75 cm in southern region and of 100 cm in northern and middle region. Canopy thickness and canopy openness are the key canopy structure parameters limiting the light interception of lower canopy during stage III. It is necessary for growers to adjust the two canopy parameters by summer pruning to improve canopy light environment.