▁different ▁phys i ological ▁processes : ▁First , ▁they ▁promote ▁the ▁germ ination ▁of ▁par as it ic ▁organ isms ▁that ▁grow ▁in ▁the ▁host ▁plant ' s ▁roots , ▁such ▁as ▁Str iga ▁l ute a ▁and ▁other ▁plants ▁of ▁the ▁genus ▁Str iga . ▁Second , ▁str ig ol act ones ▁are ▁fundamental ▁for ▁the ▁recognition ▁of ▁the ▁plant ▁by ▁sym bi otic ▁fung i , ▁especially ▁ar bus cular ▁my cor rh iz al ▁fung i , ▁because ▁they ▁establish ▁a ▁mut ual istic ▁association ▁with ▁these ▁plants , ▁and ▁provide ▁ph osph ate ▁and ▁other ▁soil ▁nut ri ents . ▁Third , ▁str ig ol act ones ▁have ▁been ▁identified ▁as ▁branch ing ▁in hib ition ▁h orm ones ▁in ▁plants ; ▁when ▁present , ▁these ▁comp ounds ▁prevent ▁excess ▁bud ▁growing ▁in ▁stem ▁terminal s , ▁stopping ▁the ▁branch ing ▁mechanism ▁in ▁plants . ▁ ▁Str ig ol act ones ▁compr ise ▁a ▁diverse ▁group , ▁but ▁they ▁all ▁have ▁core ▁common ▁chemical ▁structure , ▁as ▁shown ▁in ▁the ▁image ▁to ▁the ▁right . ▁The ▁structure ▁is ▁based ▁on ▁a ▁tr icy clic ▁la ct one ▁linked ▁to ▁a ▁hydro x ym eth yl ▁but en ol ide ; ▁the ▁former ▁is ▁represented ▁in ▁the ▁figure ▁as ▁the ▁A - B - C ▁part , ▁while ▁the ▁latter ▁is ▁the ▁D ▁part ▁of ▁the ▁mole c ule . ▁It ▁is ▁important ▁to ▁note ▁that ▁most ▁str ig ol act ones ▁present ▁variations ▁in ▁the ▁ABC ▁part , ▁but