Method for the physical characterization of substrates using centrifugation

The characterization of substrate properties supports the correct choice of components and directs management decisions in container cultivation. There are several systems of analysis, however, the routine procedures to determine the water retention curve (WRC) are time consuming and inaccurate. This study proposed a reproducible, less time-consuming, and easy to perform method for physical characterization of substrates. We used Sphagnum peat, coconut powder, carbonized rice husk, expanded vermiculite, and expanded clay in isolation. The WRC was obtained at tensions 0, 10, 50, and 100 hPa using the method of Büchner funnel, the European standard (CEN-EN13041), and by the centrifugation method of samples. In centrifugation, tensions were simulated by combining the angular velocity, sample height, and radius measured from the sample outermost point to the central point of the centrifuge. Three rotations were applied (230; 520 and 730 rpm), testing the centrifugation time for each tension and then the volumetric water content was compared between the methods. The results showed a positive correlation (p < 0.001) between the centrifugation and standard methods, considering that the centrifugation time required for moisture stabilization varied according to the material analyzed and the tension applied. However, the time required to obtain a report was reduced by half. Sample centrifugation is a promising method, ensuring that the tensile force actually acts on the entire sample to determine the water retention curve of the substrate also reducing the duration of the analyses.

The physicochemical properties of fruits and seed germination of Campomanesia aurea O. Berg / Características físico-químicas de frutos e germinação de sementes de Campomanesia aurea

Campomanesia aurea is a potentially ornamental native fruit shrub. There are no studies on the seed germination capacity and fruit properties of the species. Therefore, the main goal of this paper was to describe the seed germination and the physical and chemical properties of fruits from two C. aurea accession areas. The study was conducted with fruits collected from two native vegetation areas located inthe Morro do Osso Natural Park and in the municipality of Barão do Triunfo, Brazil. Physical and chemical analyzes, seed counting and germination tests were performed. Results were submitted to ANOVA and the means were compared by t test at 5% error probability. C. aurea has oblong-shaped fruits weighting around 1.26 g with a high content of vitamin C. Each fruit usually has four intact seeds of which 3% are polyembryonic. Seed germination averaged 93% in 20 days. It is concluded that the C. aurea fruitscollected from two different accession areas differ in the concentration of TSS, TSS/TA ratio and vitamin C content, but not physically. Seeds have shown a high germination rate.(AU)

Campomanesia aurea é uma planta nativa e frutífera de porte arbustivo com potencial ornamental. Ainda não foram encontrados trabalhos que abordem as características dos frutos e acapacidade de germinação das sementes dessa espécie. O objetivo deste trabalho foi caracterizar as propriedades físicas e químicas dos frutos e a germinação das sementes de dois acessos de C. aurea. O estudo foi conduzido com frutos coletados em áreas de vegetação nativa localizadas no Parque NaturalMorro do Osso, em Porto Alegre, e em Barão do Triunfo, RS. Realizaram-se análises físicas e químicas, contagem de sementes e teste de germinação. Os resultados foram submetidos à ANOVA e as médiasforam comparadas pelo teste t a 5%. Os frutos de C. aurea tem formato oblongo, pesam em média 1,26 g e apresentam elevado conteúdo de vitamina C. Cada fruto possui em média quatro sementes íntegras, sendoque 3% são poliembriônicas. A germinação média é de 93% e ocorre em 20 dias. Concluiu-se que os frutosde C. aurea coletados a partir de dois acessos diferem na concentração de TSS, na relação TSS/TA e no teor de vitamina C, entretanto, não há diferenças quanto às características físicas. As sementes da espéciepossuem alta germinação.(AU)

The physicochemical properties of fruits and seed germination of Campomanesia aurea O. Berg / Características físico-químicas de frutos e germinação de sementes de Campomanesia aurea

Campomanesia aurea is a potentially ornamental native fruit shrub. There are no studies on the seed germination capacity and fruit properties of the species. Therefore, the main goal of this paper was to describe the seed germination and the physical and chemical properties of fruits from two C. aurea accession areas. The study was conducted with fruits collected from two native vegetation areas located inthe Morro do Osso Natural Park and in the municipality of Barão do Triunfo, Brazil. Physical and chemical analyzes, seed counting and germination tests were performed. Results were submitted to ANOVA and the means were compared by t test at 5% error probability. C. aurea has oblong-shaped fruits weighting around 1.26 g with a high content of vitamin C. Each fruit usually has four intact seeds of which 3% are polyembryonic. Seed germination averaged 93% in 20 days. It is concluded that the C. aurea fruitscollected from two different accession areas differ in the concentration of TSS, TSS/TA ratio and vitamin C content, but not physically. Seeds have shown a high germination rate.

Campomanesia aurea é uma planta nativa e frutífera de porte arbustivo com potencial ornamental. Ainda não foram encontrados trabalhos que abordem as características dos frutos e acapacidade de germinação das sementes dessa espécie. O objetivo deste trabalho foi caracterizar as propriedades físicas e químicas dos frutos e a germinação das sementes de dois acessos de C. aurea. O estudo foi conduzido com frutos coletados em áreas de vegetação nativa localizadas no Parque NaturalMorro do Osso, em Porto Alegre, e em Barão do Triunfo, RS. Realizaram-se análises físicas e químicas, contagem de sementes e teste de germinação. Os resultados foram submetidos à ANOVA e as médiasforam comparadas pelo teste t a 5%. Os frutos de C. aurea tem formato oblongo, pesam em média 1,26 g e apresentam elevado conteúdo de vitamina C. Cada fruto possui em média quatro sementes íntegras, sendoque 3% são poliembriônicas. A germinação média é de 93% e ocorre em 20 dias. Concluiu-se que os frutosde C. aurea coletados a partir de dois acessos diferem na concentração de TSS, na relação TSS/TA e no teor de vitamina C, entretanto, não há diferenças quanto às características físicas. As sementes da espéciepossuem alta germinação.

The physicochemical properties of fruits and seed germination of Campomanesia aurea O. Berg

Campomanesia aurea is a potentially ornamental native fruit shrub. There are no studies on the seed germination capacity and fruit properties of the species. Therefore, the main goal of this paper was to describe the seed germination and the physical and chemical properties of fruits from two C. aurea accession areas. The study was conducted with fruits collected from two native vegetation areas located in the Morro do Osso Natural Park and in the municipality of Barão do Triunfo, Brazil. Physical and chemical analyzes, seed counting and germination tests were performed. Results were submitted to ANOVA and the means were compared by t test at 5% error probability. C. aurea has oblong-shaped fruits weighting around 1.26 g with a high content of vitamin C. Each fruit usually has four intact seeds of which 3% are polyembryonic. Seed germination averaged 93% in 20 days. It is concluded that the C. aurea fruits collected from two different accession areas differ in the concentration of TSS, TSS/TA ratio and vitamin C content, but not physically. Seeds have shown a high germination rate.

Ex vitro acclimatization of Hippeastrum reticulatum (Amaryllidaceae) using different substrates / Aclimatização ex vitro de Hippeastrum reticulatum (Amaryllidaceae) em diferentes substratos

Hippeastrum spp. are herbaceous species belonging to the family Amaryllidaceae, widely marketed worldwide as indoor plants. Aiming to characterize chemically and physically and to compare five substrates in acclimatization, micropropagated seedlings of Hippeastrum reticulatum var. striatifolium (Herb), with an average of four roots, two leaves and bulbs with a 4.7mm diameter, were transplanted to 50-cell polyethylene trays each containing the following substrates: T1 - vermiculite, T2 - carbonized rice husk (CRH), T3 - commercial (peat + vermiculite + CRH), T4 - coconut fiber, and T5 - composted Pinus bark. After transplantation, the trays were kept for 17 days at a greenhouse with intermittent irrigation by nebulization, and 80 days at a greenhouse on a bench with intermittent irrigation by capillarity. The experimental design was randomized blocks with seven replications and ten seedlings per plot. The acclimatization of seedlings was efficient for the substrates tested despite the differences verified by chemical and physical characterization. The mean survival rate was 96%. However, seedlings acclimatized in the T5 substrate showed a qualitative improvement due to a higher formation of roots, leaves and fresh matter.(AU)

Hippeastrum spp. são espécies herbáceas pertencentes à família Amaryllidaceae, muito comercializadas mundialmente como plantas envasadas para ambientes de interior. Objetivando caracterizar química e fisicamente, e comparar cinco substratos na aclimatização, mudas micropropagadas de Hippeastrum reticulatum var. striatifolium (Herb) Herb., com média de quatro raízes, duas folhas e bulbos com 4,7mm de diâmetro, foram transplantadas para bandejas de polietileno com 50 células de 50cm³ cada, contendo os substratos: T1 - vermiculita; T2 - casca de arroz carbonizada (CAC); T3 - comercial (turfa+vermiculita+CAC); T4 - fibra de coco; e, T5 - casca de pinus compostada. Após o transplante as bandejas foram mantidas por 17 dias em casa de vegetação com irrigação intermitente por nebulização, e mais 80 dias em casa de vegetação sobre bancada com irrigação intermitente por capilaridade. O delineamento experimental foi o de blocos casualizados, com sete repetições e dez mudas por parcela. A aclimatização de mudas foi eficiente nos substratos testados, apesar das diferenças obtidas na caracterização química e física, com sobrevivência média de 96%. No entanto, as mudas aclimatizadas no substrato T5 se destacaram qualitativamente, por apresentar maior formação de raízes, folhas e massa da matéria fresca.(AU)