RADIATION AND PHOTOSYNTHESIS IN KIWIFRUIT CANOPIES

Inclination angles, incident radiation, and photosynthesis were measured for leaves of kiwifruit vines in the field.
Soon after flowering, mean leaf inclination angles were 29.5° and 27.6° for vines on T-bar and pergola trellises respectively.
The diurnal integral of incident radiation for the upward-facing part of a T-bar vine exceeded that for the inclined part, by 50–100%.

The radiation saturated rate of photosynthesis increased from 8–10 μmol CO₂ m^-2 s^-1 about 1 month after leaf emergence to about 16–17 μmol CO₂ m^-2 s^-1 at 3–5 months after leaf emergence, before declining as leaves senesced in autumn.
The quantum efficiency increased marginally with leaf age.
Simulated canopy photosynthesis early in the season was strongly related to leaf area development.

II International Symposium on Kiwifruit

J.G. Buwalda, J.S. Meekings, G.S. Smith

incident PAR, leaf inclination, quantum efficiency

https://doi.org/10.17660/ActaHortic.1992.297.41