ISHS Acta Horticulturae 610: V International Symposium on Kiwifruit
WHOLE-PLANT GAS EXCHANGES AND CARBOHYDRATE METABOLISM IN KIWIFRUIT |
| Authors: | G. Vizzotto, G. Costa, M. Noferini, L. Corelli-Grappadelli |
| Keywords: | Net photosynthesis, transpiration, Actinidia deliciosa, sucrose, glucose, fructose, water relations |
| Abstract:
The gas exchanges of two cropping kiwifruit vines, which had been growing for 7 years on two scale lysimeters at the Udine University Experimental Farm, were recorded during a deep water stress/rewatering cycle between 72 and 87 DAFB. The instantaneous carbon and water exchanges were recorded on one heavily cropping and one lightly cropping vine. Crop loads were adjusted at 26 DAFB. Carbohydrate contents of fruits were followed during the study. The daily carbon uptake of the high-cropping vine was consistently higher (>30%) than the low-cropping one, both in absolute terms, and in terms of unit leaf area. Transpiration, on the other side, was higher in the low-cropping vine, in virtue of a 30% greater leaf area, probably resulting from the greater availability of resources for vegetative growth in this vine. When expressed in normalised terms (moles/leaf area) in fact, transpiration between the two vines appeared much more similar, although still slightly higher in the low-cropping one. Water shortage appeared to modify the fruit carbohydrates profile by increasing the glucose/fructose ratio, with the heavy-crop vine exhibiting a higher glucose content. On the contrary, the hexoses/sucrose ratio was reduced as a consequence of the water shortage, particularly in the low-crop plant. | |
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