||Evaluation of a System for the Imposition of Plant Water Stress.
Snow, M. D. ;
Tingey, D. T. ;
||Corvallis Environmental Research Lab., OR. ;Portland Univ., OR. Dept. of Physical and Life Sciences.
Soil water ;
Experimental data ;
Hydraulic conductivity ;
Periodic variations ;
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A system which imposes a range of water stress levels was developed and evaluated. Water stress was controlled by employing a screen to suspend roots above a water column of known height. Levels of water stress were imposed by changing water column height and/or hydraulic conductivity of the medium in the column. The system was evaluated in a series of growth chamber experiments in which sunflowers(Helianthus annuus) were given three levels of water availability for a period of 3 weeks. Third leaf midday water potentials at the end of the trials ranged from -0.73+ or -0.04 to -2.35+ or -0.17 megapascals in water stressed plants compared to -0.04+ or - 0.02 megapascals for control plants. Repetition of experiments showed no statistical differences in leaf water potentials, plant leaf areas, or plastochron indices between trials.