ICOM1 Abstract

ALVARENGA, FLAVIA1, ROSADO, SEBASTIAO1 & SIQUEIRA, JOSE2. 1Ciencias Florestais and 2Ciencia do Solo, Universidade Federal de Lavras. Lavras -MG. 37200-000. Brazil. Growth and phenotypic stability of ecotypes of Trema micrantha Brume (Ulmaceae) as affected by AM fungus inoculation and superphosphate Growth response and phenotypic stability of the pioneer wild woody specie T. micrantha from different seed sources to increased phosphorus rates and inoculation with the arbuscular mycorrhizal fungus Glomus etunicatum (Ge) were studied in an 5x2x4 factorial design composed of five P-rates (0, 60, 120, 240 and 480ppm), two mycorrhizal conditions (I- inoculated and NI-non-inoculated) and four seed sources (designated as S1...S4). The study was conducted in a grasshouse using a soil-mix with pHwater=7.0 and Mehlich-P=2, 14, 25, 25, 272µg.g-1 soil. Seedlings from all sources grew better when inoculated with Ge, irrespective to P-rates. Root colonization (RC) and mycorrhizal dependency (MD) were maximum when P was not added to soil-mix. In absence of P, RC was high ranging from 66.5 to 93.1% whereas MD was low ranging from 8.8 to 25.2%. There was no correlation between RC and MD. Linear regression coefficients (b) for shoot dry weight as related to environmental index (P-rates) were used to assess seed source stability by the Finlay and WilknsonÕs method. Stability for non-inoculated and inoculated seedlings differed only for seed source S2 with values of b=0.53 and 0.33 for NI and I plants, respectively. Therefore, indicating mycorrhizal contribution to increased stability, which means higher adaptability of I plants to varied soil P- availability.