View article

The interactive effects of light and drought on water relations and soluble sugars were addressed on Quercus suber L. seedlings grown under the combination of four irradiances and two soil water contents. Leaf water potentials at predawn and midday were lower for water stressed seedlings, independently of light environment. Osmotic potentials at full (100) and zero turgor (0) decreased with drought, under the four light treatments. However, the decline was greater with the development of water stress under the two treatments of higher light availability. The higher soluble sugar concentrations in seedlings grown under higher irradiances provoked a decrease of 0. The decrease in 100 and 0 in moderate stressed seedlings was accompanied by an increase in max. The lower ability for osmotic adjustment in seedlings grown under moderate water stress and low light environment suggested a lower efficiency in developing physiological mechanisms for …