LAUSR

Abstract Germination and postgermination are essential processes in plant establishment, which are affected by several biotic and abiotic factors. In this job we performed an experiment to evaluate the effect of the arbuscular – mycorrhizal fungi and mercury pollution in postgerminated seedlings of Lactuca sativa, assessing their morphogenesis and cell architecture. Seeds of L. sativa were planted in substrates polluted with mercury with and without arbuscular mycorrhizae. The colonization percentage in seedlings, root length and cell morphology state were measured with histological staining in seedlings harvested seven days after planting. It was found that arbuscular – mycorrhizae enhance root elongation and seedling development, but do not prevent cell damage in roots and hypocotyl caused by oxidative stress. Mercury and arbuscular – mycorrhizal fungi effects where more sharpen in roots than in hypocotyl. It is hypothesized that the better condition of mycorrhizal seedlings occurs due to the nutritional benefits that mycorrhizae cause in these seedlings.