Capacidade de enraizamento de estacas de quatro cultivares de Vitis L. (Vitaceae) relacionada com os aspectos anat\uf4micos

A estaquia é o método de propagação vegetativa mais utilizado e apresenta como ponto crítico o início do desenvolvimento de um sistema radicular funcional. A estrutura anatômica da estaca pode interferir no processo de enraizamento de algumas espécies, todavia em videira não há informações a respeito. O objetivo deste trabalho foi avaliar a capacidade de enraizamento de estacas de cultivares de Vitis, com ênfase aos aspectos anatômicos. Os quatro cultivares estudados foram: Vitis labrusca L. cv. Bordô, V. rotundifolia Michx. cv. Topsail e os porta-enxertos híbridos entre V. berlandieri Planch. × V. riparia Michx., 'Kobber 5BB' e 'SO4'. Destes cultivares apenas 'Topsail' apresentou dificuldade de enraizamento. Após 77 dias do plantio das estacas, foi observada uma baixa capacidade de enraizamento do cv. Topsail em relação aos outros três cultivares analisados. Também observou-se uma alta porcentagem de estacas vivas, porém não enraizadas, e a ausência de calos neste cultivar. Esses dados podem indicar a existência de fatores endógenos do cv. Topsail que dificultam o enraizamento das estacas. As características anatômicas da base das estacas do cv. Topsail diferiram das demais por manter as calotas de fibras no floema primário, pela presença de floema secundário reduzido com faixas radiais de fibras. Desse modo, a dificuldade de enraizamento desse cultivar pode estar relacionada a barreiras anatômicas

Association of Genetic Variants With Primary Open-Angle Glaucoma Among Individuals With African Ancestry

Item does not contain fulltextImportance: Primary open-angle glaucoma presents with increased prevalence and a higher degree of clinical severity in populations of African ancestry compared with European or Asian ancestry. Despite this, individuals of African ancestry remain understudied in genomic research for blinding disorders. Objectives: To perform a genome-wide association study (GWAS) of African ancestry populations and evaluate potential mechanisms of pathogenesis for loci associated with primary open-angle glaucoma. Design, Settings, and Participants: A 2-stage GWAS with a discovery data set of 2320 individuals with primary open-angle glaucoma and 2121 control individuals without primary open-angle glaucoma. The validation stage included an additional 6937 affected individuals and 14917 unaffected individuals using multicenter clinic- and population-based participant recruitment approaches. Study participants were recruited from Ghana, Nigeria, South Africa, the United States, Tanzania, Britain, Cameroon, Saudi Arabia, Brazil, the Democratic Republic of the Congo, Morocco, Peru, and Mali from 2003 to 2018. Individuals with primary open-angle glaucoma had open iridocorneal angles and displayed glaucomatous optic neuropathy with visual field defects. Elevated intraocular pressure was not included in the case definition. Control individuals had no elevated intraocular pressure and no signs of glaucoma. Exposures: Genetic variants associated with primary open-angle glaucoma. Main Outcomes and Measures: Presence of primary open-angle glaucoma. Genome-wide significance was defined as P C) with primary open-angle glaucoma (odds ratio [OR], 1.32 [95% CI, 1.20-1.46]; P = 2 x 10-8). The association was validated in an analysis of an additional 6937 affected individuals and 14917 unaffected individuals (OR, 1.15 [95% CI, 1.09-1.21]; P < .001). Each copy of the rs59892895*C risk allele was associated with increased risk of primary open-angle glaucoma when all data were included in a meta-analysis (OR, 1.19 [95% CI, 1.14-1.25]; P = 4 x 10-13). The rs59892895*C risk allele was present at appreciable frequency only in African ancestry populations. In contrast, the rs59892895*C risk allele had a frequency of less than 0.1% in individuals of European or Asian ancestry. Conclusions and Relevance: In this genome-wide association study, variants at the APBB2 locus demonstrated differential association with primary open-angle glaucoma by ancestry. If validated in additional populations this finding may have implications for risk assessment and therapeutic strategies