Interactions of Leaf Age, Fruiting, and Exogenous Cytokinins in Sangiovese Grapevines Under Non-Irrigated Conditions. I. Gas Exchange

¹ Istituto di Coltivazioni Arboree. Cattedra di Viticoltura, Sezione Viticola del Centro Ricerche Viticole ed Enologiche Università di Bologna, 40126 Bologna, Italy

The interactions of leaf age and gas exchange, together with modifications induced by fruiting and exogenous kinetin treatments, were investigated in field-grown Sangiovese (Vitis vinifera L.) grapevines. Analyses carried out both on a seasonal basis and within each sampling date as a function of the natural gradient of age along the shoot showed that maximum Pn occurred at 30 to 35 days of age. A progressive decline started at about 50 days and four-month-old leaves retained 45% of maximum Pn. Very young, rapidly expanding leaves (< 15 days) also showed a consistently lower Pn and water use efficiency (WUE) than recently fully expanded leaves. Differential rates of leaf senescence due to fruiting or kinetin were not observed. These data form a basis for improving the physiological understanding of widely used vineyard management operations (shoot topping, leaf removal) which normally induce variations in canopy leaf age.

Key words: leaf age, senescence, fruiting, cytokinins, photosynthesis

Submitted on December 3, 1992

This article has been cited by other articles:

				S. Poni, L. Casalini, F. Bernizzoni, S. Civardi, and C. Intrieri Effects of Early Defoliation on Shoot Photosynthesis, Yield Components, and Grape Composition Am. J. Enol. Vitic., December 1, 2006; 57(4): 397 - 407. [Abstract] [Full Text] [PDF]

				W. R. Nail and G. S. Howell Effects of Timing of Powdery Mildew Infection on Carbon Assimilation and Subsequent Seasonal Growth of Potted Chardonnay Grapevines Am. J. Enol. Vitic., September 1, 2005; 56(3): 220 - 227. [Abstract] [Full Text] [PDF]