Variability in colonization of arbuscular mycorrhizal fungi and its effect on mycorrhizal dependency of improved and unimproved soybean cultivars.

Breeding selection of germplasm under fertilized conditions may reduce the frequency of genes that promote mycorrhizal associations. This study was developed to compare variability in mycorrhizal colonization and its effect on mycorrhizal dependency (MD) in improved soybean genotypes (I-1 and I-2) with differential tolerance to drought stress, and in unimproved soybean genotypes (UI-3 and UI-4). As inoculum, a mixed native arbuscular mycorrhizal fungi (AMF) was isolated from soybean roots, showing spores mostly of the species Funneliformis mosseae. At 20 days, unimproved genotypes followed by I-2, showed an increase in arbuscule formation, but not in I-1. At 40 days, mycorrhizal plants showed an increase in nodulation, this effect being more evident in unimproved genotypes. Mycorrhizal dependency, evaluated as growth and biochemical parameters from oxidative stress was increased in unimproved and I-2 since 20 days, whereas in I-1, MD increased at 40 days. We cannot distinguish significant differences in AMF colonization and MD between unimproved and I-2. However, variability among improved genotypes was observed. Our results suggest that selection for improved soybean genotypes with good and rapid AMF colonization, particularly high arbuscule/hyphae ratio could be a useful strategy for the development of genotypes that optimize AMF contribution to cropping systems.

[Liposarcoma in the submandibular region. Clinical case]. / Liposarcoma della regione sottomandibolare. Caso clinico.

The authors report a case of liposarcoma in the sub-mandibular region, and they describe the histological species and the way of spreading. They suggest a surgical, non-demolitional therapy, that they carried radical if it is related to a strict follow-up. Anatomical and functional results, after demolishing surgical therapy, are sometimes unacceptable if the real benefits in terms of survival are considered. No supporting therapy has been used because of the presumed insensibility of the neoplasm to the chemo-radiotherapeutic treatments. At 2 years from surgical treatment no local relapses, on distance metastasis have been related.