Deep shade alters the acclimation response to moderate water streee in Quercus suber L.

• The interactive effects of shade and drought on different morphologicaland physiological traits were addressed on Quercus suber L.seedlings. In our experiment, limited light treatment (1 percent) represented the main factor constraining cork oak seedlingsgrowth. Maximal photochemical efficiency (Fv/Fm) with light15 per cent exhibited a midday fall, but under deep shade (1per cent), Fv/Fm remained constant (<0.8 values) throughoutthe day. The quantum efficiency of photosystem II (PSII) waslower under moderate drought only in deeply shaded plants. Thedrought also interacted with light through the increase of thesoluble sugar content at 100 per cent light, but not under shade.Under deep shade, soluble sugar content tended to be even lowerunder moderate drought conditions. The chlorophyll content wasnot the highest under deep shade as could be expected, whilethe efficiency of PSII was the lowest under deep shade. We concludedthat cork oak can acclimate to moderate shade (15 per cent light),but deep shade impairs some of the physiological responses tocope with low light conditions under moderate drought stress.Plants growing under deep shade were very sensitive to moderatewater stress in terms of loss of carbon fixation capacity.

Ämnesord

NATURVETENSKAP  -- Biologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences (hsv//eng)

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)