Efeito do tratamento com aminoetoxivinilglicina (AVG) na queda pré-colheita e na maturação dos frutos em macieiras

ABSTRACTApple trees cultivars Gala and Fuji were sprayed four weeks before commercial harvest with aminoethoxyvinilglycine (AVG), at doses of 0, 125, or 250 mg L-1, and assessed for preharvest fruit drop, fruit growth, and maturation on tree. In 'Gala', 64 days after AVG spraying, fruit drop for control treatment was 85%, and AVG (at 125 and 250 mg L-1) reduced it to 10%. In 'Fuji', 64 days after AVG spraying, fruit drop for control was 6%, while treatments with AVG (at 125 and 250 mg L-1) increased fruit drop to 10%. AVG was a powerful retardant of fruit maturation for 'Gala' but not for 'Fuji'. In 'Gala', the most affected attribute was the skin background color, followed, in decreasing order, by soluble solids content, the starch index, skin red color, the flesh firmness, and titratable acidity. In 'Gala', only flesh firmness retention was improved by increasing AVG dose from 125 mg L-1 to 250 mg L-1. The AVG at 250 mg L-1 inhibited "Gala" late fruit growth but not 'Fuji'. __________________________________________________________________________________ RESUMOMacieiras, das cultivares Gala e Fuji, foram pulverizadas quatro semanas antes do início da colheita comercial dos frutos com aminoetoxivinilglicina (AVG), nas concentrações de 0; 125 ou 250 mg L-1, e avaliadas quanto à queda de frutos na pré-colheita, o crescimento e maturação dos frutos. Na cultivar Gala, 64 dias após a pulverização com AVG, a queda pré-colheita no tratamento-controle era de 85%, mas os tratamentos com AVG (125 e 250 mg L-1) reduziram esta queda para 10%. Na cultivar Fuji, 64 dias após a pulverização com AVG, a queda de frutos no tratamento-controle era de 6%, e os tratamentos com AVG (125 e 250 mg L-1) aumentaram esta queda para 10%. Tratamentos com AVG retardaram substancialmente a maturação dos frutos da cultivar Gala, mas não da 'Fuji'. Na cultivar Gala, o atributo mais afetado foi a cor de fundo da casca, seguido, em ordem decrescente, pelo conteúdo de sólidos solúveis totais, índice de iodo-amido, cor vermelha da casca, firmeza de polpa e acidez titulável. Na cultivar Gala, apenas a retenção de firmeza de polpa foi significativamente aumentada com o aumento na concentração de AVG de 125 mg L-1 para 250 mg L-1. A concentração de 250 mg L-1 inibiu o crescimento final de frutos na cultivar Gala, mas não na 'Fuji'

Uso de poda verde, plásticos refletivos, antitranspirante e potássio na produção de pêssegos Using green pruning, reflective plastics, antitranspirant and potassium in peach production

O objetivo deste trabalho foi avaliar técnicas que viabilizem a produção de pêssegos de melhor qualidade, ao potencializar características externas como a coloração vermelha na epiderme e o tamanho, bem como características químicas relativas ao sabor. Num pomar comercial de pessegueiros da cultivar Maciel, no Município de Pelotas, RS, foram avaliados os efeitos da poda verde, o uso de dois tipos de plástico refletivo sob a copa das plantas, diferentes concentrações de cloreto de potássio (KCl) incorporado ao solo, com ou sem KCl via foliar e antitranspirante. O delineamento experimental utilizado foi o de blocos ao acaso. O uso de 1.200 g de KCl via solo, combinado com 10 g de KCl via foliar e poda verde, produziu coloração vermelha mais intensa na epiderme dos pêssegos. O uso de 1.600 g de KCl no solo, combinado com poda verde, produziu pêssegos com maior peso médio, maior diâmetro e baixa acidez titulável. A cobertura do solo, sob a copa das plantas, com plástico de ráfia, combinado com poda verde, resultou num maior teor de sólidos solúveis totais nos frutos. O uso dessas práticas culturais, realizadas na pré-colheita, influencia positivamente a qualidade final das frutas de pessegueiro da cultivar Maciel.<br>The objective of this work was to evaluate techniques which make possible the production of peaches of high quality by improving external characteristics, percent of red cover color, fruit size, and chemical characteristics that influence flavor, in a field peach of cultivar Maciel, in Pelotas, RS, Brazil. Effects evaluated were: vegetative pruning, the use of two types of reflective plastics under the plant canopy, the different potassium chloride concentrations incorporated to the soil, with and without foliar aplication of KCl, and the use of antitranspirant. The experiment was carried out in a randomized block design. The results showed that the use of 1,200 g of KCl applied to soil, combined with 10 g of KCl as foliar application and vegetative pruning, provided intense red coloration of the peaches epidermis. The use of 1,600 g of KCl in the soil, combined with green pruning, resulted in higher average weight, larger diameter and low titratable acidity. Soil cover with raffia plastic under plant canopy, combined with green pruning, resulted in higher soluble solids content in the fruits. These practics during preharvest influence positively the final quality of cultivar Maciel peaches

DNA methylation in Friedreich ataxia silences expression of frataxin isoform E

Epigenetic silencing in Friedreich ataxia (FRDA), induced by an expanded GAA triplet-repeat in intron 1 of the FXN gene, results in deficiency of the mitochondrial protein, frataxin. A lesser known extramitochondrial isoform of frataxin detected in erythrocytes, frataxin-E, is encoded via an alternate transcript (FXN-E) originating in intron 1 that lacks a mitochondrial targeting sequence. We show that FXN-E is deficient in FRDA, including in patient-derived cell lines, iPS-derived proprioceptive neurons, and tissues from a humanized mouse model. In a series of FRDA patients, deficiency of frataxin-E protein correlated with the length of the expanded GAA triplet-repeat, and with repeat-induced DNA hypermethylation that occurs in close proximity to the intronic origin of FXN-E. CRISPR-induced epimodification to mimic DNA hypermethylation seen in FRDA reproduced FXN-E transcriptional deficiency. Deficiency of frataxin E is a consequence of FRDA-specific epigenetic silencing, and therapeutic strategies may need to address this deficiency.SCOPUS: ar.jinfo:eu-repo/semantics/publishe