ISHS Acta Horticulturae 297: II International Symposium on Kiwifruit
LOW-TEMPERATURE AND BRIGHT-LIGHT INDUCED PHOTOINHIBITION OF PHOTOSYNTHESIS IN KIWIFRUIT LEAVES |
| Authors: | D.H. Greer, W.A. Laing |
| Keywords: | Actinidia deliciosa, photon yield, photosynthetic efficiency, photosynthetic capacity, stress |
| Abstract:
Light-limited (photon yield) and light-saturated photosynthesis (Pmax) of kiwifruit leaves is inhibited when the leaves are exposed to bright light (photoinhibition), especially at low temperatures. Exposures at 75% of full sun and at a temperature of 10 C results in a 90 and 50% loss in photon yield and Pmax respectively while exposures at 30 C result in 10 and 15% losses. Similarly, when kiwifruit leaves at 20 C are exposed to PFDs from 50 to 100% of full sun then the photon yield is photoinhibited by 18 to 60% and Pmax by 20 to 40%. Although the growth conditions can affect the susceptibility to high light stress, up to 88% of photoinhibition of photon yield and 65% of Pmax is directly attributable to the prevailing light and temperature combination that the leaves experience. As low temperatures and bright light are common conditions in kiwifruit orchards, at least in spring and autumn, the carbon balance of this crop is likely to be reduced by low-temperature induced photoinhibition. | |
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