ISHS Acta Horticulturae 528: VII International Symposium on Grapevine Genetics and Breeding
ROOTSTOCK-SCION INTERACTION MAY AFFECT DROUGHT TOLERANCE IN VITIS VINIFERA CULTIVARS. IMPLICATIONS IN SELECTION PROGRAMS |
| Authors: | F. Iacono, E. Peterlunger |
| Keywords: | Graft combination, xylem abscisic acid, abscisic acid flux |
| Abstract:
Selection for drought tolerance in Vitis vinifera is usually done on the basis of rootstock resistance to water deficit. Recently it has been demonstrated that photosynthesis and stomatal conductance are affected by the rootstock and that this effect is scion-specific. Stomatal closure is more closely related to events in the root than in the shoot and there is strong evidence that the root physiological status plays an important role in modulating shoot behaviour. Transport of chemical signals, e.g. abscisic acid (ABA), from roots to the shoot in the transpiration stream is the mechanism most often proposed to explain these responses. A research program has been developed to evaluate the possibility to understand the biological and physiological mechanisms used by vines to show such an interaction. Data showed that xylem abscisic acid (ABA) is controlled by transpiration rate and by ABA flux in transpiration stream and it is involved in modulating stomatal closure and therefore net photosynthesis. On the basis of these findings a possible model to know drought tolerance of rootstock-scion plants has been elaborated. Scion-rootstock combinations were grouped through cluster analysis in drought tolerance classes by using net photosynthetic rates under water stress conditions. The same groups were evaluated under well-watered conditions in order to identify physiological parameters able to characterize their behaviour. Scion-rootstock combinations that showed high ABA flux and low net photosynthesis under well-watered conditions were those classified in the drought tolerant groups. | |
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