Endophyte infected perennial ryegrass was able to grow in the presence of excessive Zn (Monnet et al., 2001), possibly because of a mechanism that appears to exclude Zn from roots and which is similar to that proposed by Malinowski et al. (1998a) and Malinowski and Belesky (1999a). Endophyte infection seems to exclude Zn but allow Mn to accumulate in leaves. Zinc accumulates in some soils near industrial sites; E+ plants might serve as an effective cover crop to stabilize the Zn (see Chapter 28) and its effects on wildlife habitat in the soil (Stewart and Martin, 2003). Endophyte infected plants of perennial ryegrass appear to have greater tolerance of Zn than do E- plants (Monnet et al., 2001, 2005). The response was measured in terms of damage to photosystem II function. The E+ plants were able to maintain photosynthesis and growth at higher soil Zn levels than were E- plants.