The interactive effect of phosphorus and nitrogen on "In vitro" spore germination of glomus etunicatum Becker & Gerdemann, root growth and mycorrhizal colonization

RESUMO

The effects of P and N amendment and its interactions on spore germination, root growth and colonized root length by Glomus etunicatum Becker & Gerdemann (INVAM S329) was studied "in vitro"in RiT-DNA transformed roots of Anthylis vulneraria sub sp. Sampaiana (Kidney vetch). Three N media concentrations (5, 10 and 50 mg/l) at P constant level (2 mg/l) and three P media concentrations (2, 10 and 20 mg/l) at N constant level (5 mg/l) were utilized as a treatment. Bécard & Fortin medium was used as a basal medium for root growth and colonized root length, and water/agar 0.8(per cent) media was the control for spore germination. Spore germination of G. etunicatum at low P level was reduced by N addition in relation to the control media, and at low N level addition of P stimulated spore germination. Total root length was stimulated by N addtion at low P level, but no significant difference (p<0.05) was observed among P concentrations. Colonized root lenght by G. etunicatum increased significantly (pz0,05) with P additions at low N levels. Under low P level no significant differences was found between 10 and 50 mg/l of N. These results demonstrate that the interaction between P and N affect differently spore germination, root growth and colonized root lenght.