Pattern of plasticity to irradiance levels and genotypic correlations between structural and physiological leaf traits in Iris pumila

Plasticity to irradiance and genotypic correlations between structural and physiological leaf traits in Iris pumila were investigated in an experiment conducted at a sun-exposed dune habitat in the Deliblato Sands. A sample of six native, genetically different clones were covered with a neutral screen which transmitted similar to 35% of daylight, so that one clone-half of each clone experienced reduced sunlight, while the other one full sunlight. LMA, stomatal density, psi sub(leaf), enzymatic and non-enzymatic antioxidants and lipid peroxidation were determined in unshaded and shaded leaves of the same clone. It was found that the plasticity index, PIv was higher for physiological than for structural traits. Genotypic correlations between trait pairs were high, but rarely significant, in contrast to the correlation matrices which were significantly different between unshaded and shaded leaves. Key words: light intensity, phenotypic plasticity, genotypic correlations, Iris pumila