Title : Leading Speaker for Plant Biology Conferences
Plant litter decomposition is a crucial process of nutrient cycling within ecosystems. However, many studies have shown that, apart from its several beneficial effects, organic matter decomposition can have also certain disadvantageous outcomes on other plants in terms of seed germination, seedling growth, and physiological activity. These effects have been reported to affect the next generation of the same plant species as well as the neighboring plant individuals and soil microbial communities. The aim of this work is to understand, first, the mechanism of functioning of these effects of leaf litter decomposition in the soil, also called plant-soil feedback processes or soil sickness in the agricultural field. Secondly, to test the effect of seed-associated endophytic fungi and arbuscular mycorrhizal fungi on the plant’s response to different types of litter including self-litter. For seed-associated endophytic fungi experiment, we collected the leaf material of four tree species, the decomposition process has been started in the laboratory for two ages (fresh undecomposed litter and after 120 days of decomposition). The experiment was set in a greenhouse using two plants (Trifolium repens and Triticum durum) with and without their associated endophytic fungi in the presence of several litter materials at two ages. For arbuscular mycorrhizal experiment, seedlings of Trifolium repens already grown with and without AMF were put into sheet paper and treated with different litter types at two ages (0 and after 120 days of decomposition). Results have demonstrated that away from the nutritional function, litter execute a strong inhibition effect on the plant growth, which is considered as a crucial factor in regulating plant community dynamics, since it limits their invasive capacity in new ranges. Moreover, Seed-associated endophytic fungi have demonstrated to enhance the inhibitory effect of litter in such conditions. The removal of seed-associated endophytic fungi has improved the plant’s capacity to resist litter stress. Therefore, endophytic fungi may be considered among the main causes of regulating plant-plant interactions, which restructures the plant community. Moreover, AMF have demonstrated an effect of accelerated assimilation of phytotoxic compounds released after decomposition, which means that these Fungi, in fact, have a negative effect on the next generation of the same plant species in the existence of leaf litter material.