others are involved in later stages controlling the extension of colonisation and/or the lifespan of the arbuscules and some hormones can be involved at the different stages of the symbiosis.Despite their regulatory functions as plant hormones,SLs were initially identified as signalling molecules in he rhizosphere,where they were shown to act as hyphal branching factors of AM fungi of the Gigasporaceae and germination stimulants in a number of AM fungi of the Glomeraceae.