Development of mycorrhized vitroplants of Jatropha curcas L. at different rooting stages

In this work, we attempted to assess the effects of inoculation of arbuscular mycorrhizal fungus (AMF), Glomus clarum, on the survival and development of micropropagated Jatropha curcas plantlets at different rooting stages. Elongated shoots (average 3?cm) of J. curcas, maintained for 0, 14, or 21?days on rooting medium in the presence or absence of 1?mg?L^?1 indole-3-butyric acid (IBA), were transferred to a sand:soil:vermiculite (1:1/2:1) (v:v:v) substrate. At the time of transplantation, the plantlets were either inoculated or not inoculated with G. clarum that had been monoaxenically produced in Ri-transformed carrot roots. After a 2-week acclimatization period, 100?% of the plants kept for 0 or 14?days in rooting medium survived. However, those that remained for 21?days in rooting medium displayed post-acclimatization survival rates of 93 and 89?% for plants inoculated and non-inoculated with G. clarum, respectively. Colonization rates ranged from 70 to 93?%, and the stimulatory effects of AMF were evidenced by increased phosphorus uptake by plants and increases in all evaluated growth parameters, except plant height. Plants that were not subjected to the rooting stage showed growth similar to or higher than those subjected to the rooting stage, regardless of the addition of IBA. It can be concluded that stimulatory effects of mycorrhizal fungi were observed, and that the inoculation of J. curcas proved effective during the initial period of the acclimatization phase.