Glomus intraradices

The paper reports the estab li shmcill or mycorrhi za l inrecti on or a non-mycorrhi za l Ri-T-DN A trans rormcd carrot root when co-c ultured with a su rrace sterili zcd swcd potato root scgment coloni zcd by arbusc ular mycorrhi zal (A M) rungus C. ill/rami/ices on minimal M medi um. Extensivc rungal hypha I cmergence rrom eac h cut end of the mycorrhi zal swcet potato root piece was observed in one weck old cullUres. Thes\: hyphae causcd infecti on on contacting the transrormed-carrotroot segment and produced many hyphae and spores both inside and outside the zone of the root aft er 6 week or growth. Axeni call y produced rungal propagules prolirerated on the surface of fresh minimal M medium when sub-cu ltured without any root seg ment. On repeated sub-culturing, thesc propagules did not lose their ability to grow and produced man y juveni le small spore-likc ves icles durin g thc non-sy mbiotic phase. Although these spores were morphologicall y and anatomical ly si milar to their soi l borne counter part s, they were much smaller. When pl aced in the vieinity or a fresh hairy root on the minimal medium or a Sudan grass seedling in sand eu llllre, thc axenica ll y produced AM runga l propagu les caused root in rec ti on, but the inrection characteri stics we re signiri cantl y dirfe rent to the ori ginal culture in terills o r shape (spheri cal vs oval) anc! sizc (20 ~lIn vs 45 pm) or thc intraradical ves icles. and absence or 'H' branches. Sudan grass seedlings inocu lated with the axcni call y cultured rungus showed signiri cantly (P <: 0.05) higher dry weights plant i . When compared to the plants inocu lated wi th sand cultures. the growt h paranlcters and thc pcrcentage inrec ti on werc not signifi cant ly dilTerent. However, when bot h sources o r inoc l'la werc uscd together, a sy nergistic cl'fcct on plant growth as we ll as root infection was obscrvcd.