ISHS Acta Horticulturae 708: V International Strawberry Symposium
WATER CHANNELS IN STRAWBERRY, AND THEIR ROLE IN THE PLANT¿S RESPONSE TO WATER STRESS |
| Authors: | M.M. Blanke, D.T. Cooke |
| Keywords: | Fragaria × ananassa Duch., salinity, stomata, transpiration, water transport, water potential |
| Abstract:
The objective of the present work was to demonstrate the presence of water channels in strawberry (Fragaria × ananassa Duch.) and to identify their role in the adaptation of the plant to water stress. Drought stress decreased strawberry leaf water potential from –1 to -2 MPa with a concomitant reduction in transpiration from 5.6 to 3.4 mmol H2O m-2 s-1. However, leaf water potentials remained unchanged after flooding. Similarly, membrane vesicles derived from flooded strawberry plants showed no change in water channel activity, indicating that water channels remained open. By contrast, water channel activity was reduced in drought stressed strawberry plants. The effect of flooding on water relations of strawberry was less pronounced than that of drought, a result that cannot be explained by increased ABA. Stomatal closure under drought could be attributed to increased delivery of ABA from roots to the leaves. However, stomata closed more rapidly in leaves of flooded strawberry than drought stressed strawberry, despite ABA delivery from the roots in the xylem to the leaves being strongly depressed. In flooded plants, turgor may be preserved by maintaining root pressure and an electrochemical and ion gradient, assuming water channels remain open. The lesser effects of flooding could be explained in terms of water channel activity. In conclusion, strawberry plants appear to be more affected by drought than by flooding. If water channels act as a hydrostatic signal, under flooding conditions, water channels might be maintained in the open position, whereas under drought, they are likely to close. Closure of the water channels may be the first stress signal, followed by ABA, to cause stomatal closure in plants including strawberry. | |
Download Adobe Acrobat Reader (free software to read PDF files) | |
