<p> A salinidade dos solos é um dos mais importantes fatores de estresse abiótico, afetando negativamente diversos aspectos da fisiologia e bioquímica das plantas. Este trabalho teve por objetivo avaliar o efeito do pré-condicionamento de sementes de <em>Gallesia integrifolia </em>sob de estresse salino com nitrato de potássio (KNO<sub>3</sub>) e nitropurinato de sódio (SNP). As sementes foram tratadas através do pré-condicionamento de imersão em soluções com cinco concentrações de KNO<sub>3</sub> (0,0, 0,01, 0,1, 1 e 10 mg L-1) e de SNP (0, 0,01, 0,1, 1 e 10 mg L<sup>-1</sup>) por uma hora. Em seguida, as sementes foram distribuídas em folhas de papel filtro previamente umedecidos com soluções salinas em três potenciais osmóticos (0,0, -0,6 e - 1,2 MPa), sendo os rolos de papel mantidos em câmara de germinação do tipo BOD sob temperatura alternada de 20-30 ºC com fotoperíodo de 8/16 h durante 22 dias. Observou-se que o menor potencial osmótico acarretou redução das médias para todas as variáveis avaliadas. O potencial osmótico de -1,2 MPa influenciou negativamente a germinação e vigor de sementes de pau d’alho. KNO<sub>3</sub> e SNP na concentração de 1 mg L<sup>-1</sup> proporcionam redução do efeito salino nas sementes.</p>
The objective of this study was to analyze the spatial distribution of the attributes that determine the physiological quality of Joannesia princeps seeds. Seeds were collected, individually from, 40 mother plants in the Horto Florestal Municipal Laerth Paiva Gama, in Alegre-ES, which constituted the georeferenced sampling mesh. For germination, the seeds tegument was cracked and was held the imbibition in gibberellic acid GA3 500 mg L-1 for 24 h in environmental chamber with temperature adjusted to 30 ºC. The seeds were sown in plastic bags of ± 600 cm3 containing soil+sand+manure in the proportion of 1:1:1. On the 65th day after sowing, the following variables were analised: emergence (E), emergence speed index (IVE), root length (CR), diameter of base (DC), shoot length of the aerial part (CPA), fresh mass of the root system (MFSR), fresh mass of the aerial part (MFPA), dry mass of the root system (MSSR) and dry mass of the aerial part (MSPA). Data were subjected to descriptive statistics, geostatistics and kriging. With the exception of CPA and MFSR, it was found spatial dependence for the other studied variables: E, IVE, CR, DC, MFPA, MSSR e MSPA; varying of 14,0 a 47,5 m, so that the lowest range for the CR and longer range and degree of spatial dependence for the IVE. The analysis of the spatial distribution of the physiological quality of seeds of J. princeps can be used as a tool to define the sampling region of seeds with high and low vigor.
Joannesia princeps, popularmente conhecida como cutieira, é uma Euphorbiaceae endêmica do Brasil, cuja madeira é utilizada para diversos fins industriais. As sementes possuem aproximadamente 37% de óleo útil para fins industrias e medicinais, servem de alimento para cutias (Dasyprocta azarae), além de apresentarem destacada importância na sucessão ecológica em áreas degradas. Objetivou-se estudar a germinação, fenologia e a morfometria de frutos, sementes e plântulas de Joannesia princeps. Foram utilizados 1000 frutos de Joannesia princeps colhidos de 40 matrizes de Mata Atlântica do Entorno do Caparaó, que compõem um bosque existente no Horto Municipal da cidade de Alegre - ES, nos quais foram analisados os atributos qualitativos em relação à morfologia. Na análise biométrica, foram analisados: comprimento, diâmetro e espessura. As análises das plântulas foram conduzidas periodicamente no 6°, 7º, 14º, 21º, 28º, 35º e 42º dia após a germinação, utilizando-se quatro repetições de 15 plântulas normais e sadias para as descrições. Observou-se que as raízes mudaram o tom de sua coloração de esbranquiçada para branco-amarelada entre o 14º para o 21º dia após a germinação (DAG), enquanto o hipocótilo, nos estádios iniciais, apresentava coloração avermelhada passando para verde após o 14º DAG. Os demais órgãos não apresentaram mudanças consideráveis, contudo, biometricamente, todos os órgãos apresentaram acréscimo nas suas dimensões, conforme a evolução do desenvolvimento. Os aspectos morfológicos descritos e ilustrados demonstraram-se estáveis e, portanto, informativos para a caracterização e identificação da espécie em processo de germinação e nos primeiros estádios de desenvolvimento.
This research studied growth and yield of Syagrus schizophylla, an extinction-endangered ornamental palm, grown under five light gradients. The treatments were: G1 - PAR=1234.10 μmol photons m-2 s-1, G2 - PAR=913.16 μmol photons m-2 s-1, G3 - PAR=666.34 μmol photons m-2 s-1, G4 - PAR=419.56 μmol photons m-2 s-1 and G5 - PAR=534.77 μmol photons m-2s-1. Before the experiment and at three, five and seven months of treatment, growth (plant height, collar diameter, number of leaves, petiole length, leaf length and width), gas exchange, chlorophyll a, and leaf green color intensity were assessed. The highest net photosynthetic rates were observed in plants under G2, G3 and G4. Values of maximum quantum efficiency (Fv/Fm) over 0.75 were observed under G2. At seven months, estimated SPAD values were 36 in G2 plants and 32 in G1 plants. According to the Dickson quality index (DQI), presented the highest growth and development rates. We conclude that G2 suits plants to be transplanted into the field, whereas G3 would be best for plants grown under shade environments. Highlights: Syagrus schizophylla is an extinction endangered ornamental palm. One layer of Red Chromatinet® 50% should be recommended for the first year of growth of schizophylla plants to be later transplanted to the field. Two Red Chromatinet® 50% layers would be best for plants meant to grow under shade environments. The highest net photosynthetic rates were observed in plants under G2, G3 and G4.
Article AbstractThe interest in Syagrus schizophylla as an ornamental palm tree and the demand for conservation and preservation of the species led to this research. The objective was to study the physiological characteristics of its germination at different temperatures, as well as the morphological and biometrical characterization of diaspores and seedlings at the initial stages of growth and development. The research was divided into two experiments. In the first one, the aim was to identify the water absorption phases of seeds during germination under five scarification treatments as follows: intact diaspores, scarified diaspores, diaspores with endocarp rupture and intact seeds. In the second experiment, germination was tested at 25, 30 e 25 -35 ºC; the first germination count, seedling emergence, abnormal seedlings, non-germinated seeds, the emergence curve, the emergence speed index and the mean time of emergence were evaluated. Afterwards, the morphological and biometrical characteristics of diaspores and seedlings were described. The water absorption curve observed under the different scarification treatments showed different water absorption patterns. Emergence percentages were 53, 61 and 47% at 25, 30 and 25 -35 ºC, respectively. The highest emergence speed index was obtained at 30 ºC. The mean time of emergence was 30 days, approximately, under all the temperatures tested. The diaspores showed a great variability in both shape and size, presenting a globular to ovoid shape with an average length of 2.44 cm and an average width of 1.39 cm. The germination can be classified as hypogeal crypto cotyledonal of the remote-tubular type.
Phoenix roebelenii is a palm species widely used in Brazil due to its exuberant leaves and adaptability to different climatic variations. For proper propagation, detailed information about seed viability, vigor and longevity subjected to dehydration and storage is yet to be obtained. For this purpose, the present research comprised two stages. The first one aimed at evaluating the response of seeds to desiccation and storage based on formal protocols. In the second stage, seeds were desiccated to 33, 30, 25, 23, 20, 18, 16, 12, 10 and 7% of water content by monitoring water loss in a convection oven at 35±2°C. After reaching each established water content, the seeds were subjected to germination tests. At 65 days after sowing, root length, root area, volume and diameter, shoot and eophyll length, and total seedling fresh and dry weights, were measured. Significant increases in germination and eophyll length were observed for lower seed water contents. Aversely, collar diameter decreased with seed desiccation. Highlights: Phoenix roebelenii seeds are orthodox. Reduced seed water content increased the percentage of germination, the germination speed index, and eophyll length of Phoenix roebelenii seedlings. Significant increases in germination and eophyll length were observed for lower seed water contents. Aversely, collar diameter decreased with seed desiccation.
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