Epigenetic rather than genetic factors may explain phenotypic divergence between coastal populations of diploid and tetraploid Limonium spp. (Plumbaginacaeae) in Portugal

BACKGROUND: The genus Limonium Miller comprises annual and perennial halophytes that can produce sexual and/or asexual seeds (apomixis). Genetic and epigenetic (DNA methylation) variation patterns were investigated in populations of three phenotypically similar putative sexual diploid species (L. nydeggeri, L. ovalifolium, L. lanceolatum), one sexual tetraploid species (L. vulgare) and two apomict tetraploid species thought to be related (L. dodartii, L. multiflorum). The extent of morphological differentiation between these species was assessed using ten diagnostic morphometric characters. RESULTS: A discriminant analysis using the morphometric variables reliably assigns individuals into their respective species groups. We found that only modest genetic and epigenetic differentiation was revealed between species by Methylation Sensitive Amplification Polymorphism (MSAP). However, whilst there was little separation possible between ploidy levels on the basis of genetic profiles, there was clear and pronounced interploidy discrimination on the basis of epigenetic profiles. Here we investigate the relative contribution of genetic and epigenetic factors in explaining the complex phenotypic variability seen in problematic taxonomic groups such as Limonium that operate both apomixis and sexual modes of reproduction. CONCLUSIONS: Our results suggest that epigenetic variation might be one of the drivers of the phenotypic divergence between diploid and tetraploid taxa and discuss that intergenome silencing offers a plausible mechanistic explanation for the observed phenotypic divergence between these microspecies. These results also suggest that epigenetic profiling offer an additional tool to infer ploidy level in stored specimens and that stable epigenetic change may play an important role in apomict evolution and species recognition

Influence of storage conditions on fruit quality of ‘Royal Time’ and ‘Royal Summer’ peach cultivars

Peach is a very perishable climacteric fruit whose firmness may decay rapidly depending on the temperature. Refrigeration is usually used to delay ripening and maintain fruit quality. However, often temperature storage conditions are not optimized. This work aims to characterize the storage conditions (temperature and humidity) of three peach producers of Beira Interior region, Portugal. Additionally, correlate those conditions with peach quality evolution comparing two peach cultivars – Royal Summer and Royal Time – with similar harvest dates but very different acidity content. The three refrigeration chambers monitored have very distinct conditions of average air temperature, namely 8.29±3.53 °C (local C), 5.50±0.88 °C (local G) and 0.80±0.83 °C (local L) but similar high humidity, in an average range of 90%-98%. At harvest time, major differences were in fruit firmness and acidity. ‘Royal Summer’ firmness was 6.61 kgf and ‘Royal Time’ was 5.20 kgf. For all storage conditions, fruit firmness decrease faster for ‘Royal Time’ cultivar than for ‘Royal Summer’. The results suggest that in general farmers use inadequate range temperature for long storage period. For short periods of 7 days, conditions like those of local G allow fruit quality maintenance like firmness and loss of weight without problems of chilling injury, and, simultaneously, save energy that is also not only a desirable international goal but also contributes to decrease of production costs.O pêssego é um fruto climatérico, altamente perecível, cuja firmeza diminui rapidamente dependendo da temperatura de conservação. A refrigeração é o processo utilizado para atrasar a maturação e manter a qualidade embora, em muitos casos, a temperatura de refrigeração não seja otimizada. Este trabalho pretende caracterizar as condições de refrigeração (temperatura e humidade) das câmaras de três produtores de pêssego da Beira Interior. Adicionalmente, pretende também relacionar essas condições com a evolução da qualidade dos frutos utilizando duas cultivares – Royal Summer e Royal Time – com data de colheita semelhante, mas teor de acidez distinto. As três câmaras de refrigeração monitorizadas corresponderam a condições bastante diferentes de temperatura, nomeadamente, 8,29±3,53°C (local C), 5,50±0,88°C (local G) e 0,80±0,83°C (local L), mas semelhantes em termos de humidade, que está compreendida entre 90% e 98%. À colheita, as maiores diferenças observadas foram a firmeza e acidez. A firmeza dos pêssegos da ‘Royal Summer’ foi de 6,61 kgf e a da ‘Royal Time’ foi de 5,20 kgf. Para todas as condições de conservação, a firmeza diminuiu mais rapidamente na ‘Royal Time’. Os resultados sugerem que, em geral, os produtores usam intervalos de temperatura inadequados para períodos de conservação longos. Contudo, considerando períodos curtos, entre 7 dias, as condições observadas no local G permitiram manter a qualidade como firmeza e perda de peso, sem se observarem danos por frio. Simultaneamente, permitem economizar energia o que é um objetivo internacional e contribui para a diminuição dos custos de produção.This research work is part of project “PrunusPÓS – Otimização de processos de armazenamento, conservação em frio e embalamento inteligente no pós-colheita de pêssego e cereja”, n.º PDR2020-101-031695 (PDR 020), Portugal 2020. The authors would like to thank the producers who allowed the use of the refrigeration chambers and the respective monitoring of its conditions.info:eu-repo/semantics/publishedVersio

Panorâma sócio-econômico e evidências ambientais de impactos decorrentes da pressão antrópica pela expansão da cultura do açaí (Euterpe oleracea) na ilha do Murutucu, Pará.

No presente trabalho investigou-se aspectos que evidenciassem respostas ambientais à pressão antrópica decorrente da expansão do açaí na ilha de Murutucu para subsidiar ações conservacionistas na área de estudo