Salinity and pH Stress on Lolium multiflorum Lam. Germination

Direct spreading on agricultural lands of olive mill wastewaters (OMWs) may represent an environmentally friendly disposal method. In the olive oil-producing Mediterranean regions OMWs spreading on soil represents a simple and cheap alternative to detoxification techniques that result in final waste discharge into natural water bodies (Barbera et al., 2013). Additionally, because these regions are characterized by serious deficiencies in water availability and soil organic matter, the reuse of OMWs could be particularly beneficial (Piotrowska et al., 2006) and may contribute to a more sustainable agricultural system. However, the agronomic use of OMWs is limited by some constraints, such as oil and grease (Amaral et al., 2008; Ouzounidou et al., 2008), high salinity, acidity, and phenolic compounds content (Hanifi e El Hadrami, 2008) that exert an antimicrobial action (Obied et al., 2005) and a phytotoxic effect. Many authors (El Hadrami et al., 2004; Isidori et al., 2005) studied OMWs polyphenol phytotoxic effects, but only few (Pierantozzi et al. 2011) the effects of salinity and acidity on seed germination. High levels of lethality or seed germination inhibition of Lactuca sativa L. induced by OMWs were attributed by Pierantozzi et al. (2011) not only to polyphenols content, but also to acid pH, salts and other organic compounds. Positive effects of pH enhancement on seed germination had been reported by Suthar et al. (2009). In a previous research (unpublished data), the addition of Ca(OH)2 to activated charcoal (AC), determined a pH raise in the OMWs solutions and a significant enhancement on Lolium seed germination up to 79% as compared to the effects of AC alone (43%). With this in mind, on five Lolium multiflorum cultivars, a research was carried out to study the effects on germination of two levels of salinity induced by two different salts, and two pH