ISHS Acta Horticulturae 449: II International Symposium on Irrigation of Horticultural Crops
THE RESPONSE OF PISTACHIO TREES TO WATER STRESS AS AFFECTED BY TWO DIFFERENT ROOTSTOCKS |
| Author: | C. Germana |
| Keywords: | Pistacia vera, Pistacia terebinthus, Pistacia atlantica, xylem potential, net photosynthesis, transpiration rate, temperature difference |
| Abstract:
A research was conducted to assess the response of pistachio plants to water stress, in terms of intensity in selected physiological activities. The plants were 12 years old trees of the cultivar 'Nostrale' grafted on rootstocks of P. terebinthus and P. atlantica; variables were the rootstocks and the irrigation regime ('wet'/'dry'). The main processes and parameters observed included net photosynthetic activity (CER), transpiration rate (TR), water xylem potential (Y), stomatal conductance (SC), temperature difference between canopies and the surrounding atmosphere (DT). Environmental conditions such as vapour pressure deficit (VPD) and photosynthetically active radiation (PAR) were also monitored. Results showed a surprising response to water stress from plants grafted on both rootstocks, since xylem potential never fell below - 0.5 MPa even in unirrigated plants under the most demanding conditions, while photosynthesis and transpiration rate were rather little affected by water stress. Temperature differences between irrigated and stressed plants remained negative (i.e. leaves were cooler than atmosphere) in all cases in plants grafted on P. atlantica whereas were almost constantly positive in those grafted on P. terebinthus. P. atlantica induced also a more intense transpiration and net photosynthetic activity, particularly in water-stressed plants, when compared to P. terebinthus. All the above findings point out a particular attitude of pistachio plants to thrive under water-stressed conditions and show promise for the possibility of achieving even better results through a selection of appropriate rootstocks. | |
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