ISHS Acta Horticulturae 526: V International Symposium on Grapevine Physiology
SAP FLOW AND STEM CONDUCTIVITY OF POTTED WATER STRESSED GRAPEVINES. |
| Authors: | C. Lovisolo, A. Schubert, E. Peterlunger, S. Ferraris |
| Keywords: | embolism, vessels, Vitis vinifera, xylem |
| Abstract:
Potted plants of Vitis vinifera cv.Freisa were water stressed for 40 days; after this period sap flow was measured by the Stem Heat Balance method. Hydraulic conductivity (kh) at constant pressure gradient (0.1 MPa m-1) and the average transectional area of xylem vessels were measured after leaf fall on stem segments along the shoot. For all the plants the pattern of water flow during the day was similar and it depended mainly from the evapotranspirative demand, but water-stressed plants had always lower flow than control irrigated plants. Mean leaf area was 15% higher in irrigated plants, while shoot transectional area did not show differences between the 2 treatments. Shoot hydraulic conductivity decreased from the base towards the shoot apex and was greater in irrigated plants than in the water stressed ones. The transectional area of xylem vessels was positively correlated with Kh for different thesis and for different positions along the shoot. In vines submitted to water stress, a decreased size of xylem vessels is linked to limited Kh and transpiration flow. This suggests that in the grapevine the regulation of xylem development may contribute to drought resistance. | |
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