Light distribution oncitrus canopyaffects physiological parameters and fruiting pattern

Light interception by the orange tree canopy during flower bud differentiation and subsequent
flowering and fruit setting has been monitored by continuous data recording from 48 silicon
cells distributed in different canopy zones. Two experimental conditions have been tested:
trees artificially shaded by a black nylon net cage, and non-shaded trees. Observations were
made on the total radiation accumulated in the different canopy zones, and they were related
to photosynthetic activity, stomatal conductance) flowering and fruiting pattern, and fruit
quality. The different light distribution affected both photosyntesis and stomatal conductance:
in fact, they were both drastically reduced in shaded trees, and a significant decrease was also
found in both shaded and unshaded trees in relation to different canopy zones. A significant
decrease of flowering and fruit setting was found from the top of the canopy to the bottom
and from outside to inside, in relation to the different amount of radiant energy availability.
Finally significant differences were found on fruit quality.