Characterization of volatile production during seed storage

This paper contributes to the understanding of factors that regulate seed longevity and mechanisms that cause seed deterioration during storage. The over-all goal is to characterize the types of chemical reactions that occur in dry seeds and to relate these to the properties of the seed glassy matrix and the inevitable decline in seed quality and viability. Oxidation and peroxidation reactions occur in stored seeds and are implicated in chemical degradation. Oxidation of macromolecules gives rise to low molecular weight carbonyl compounds, many of which are volatile and so escape into the airspace of the storage container. The identity of volatile compounds indicates the nature of chemical reactions. Production of volatile compounds from seeds of different species was investigated. Volatile composition produced by seeds differs with the species: species such as Carum carvi were detected to produce large amounts of volatile compounds, while others, such as Eruca sativa, produced low quantities of only a few compounds. Qualitative and quantitative differences in volatile composition were noted as a function of storage RH: above about 30% RH glycolysis-like reactions increase with increasing RH, and below about 30% RH peroxidation-like reactions increase with decreasing RH. Assessment of volatile production from seeds during storage provides a probe to address questions about the nature and kinetics of chemical reactions that occur in the glassy matrix of stored seeds. This information reveals important information about the glass such as the proximity of reacting ligands and inter- or intra-molecular motions required to effect chemical reactions. Moreover, it could be developed as a non-invasive and early detection method of seed ageing rates

Seed germination characteristics of Phillyrea angustifolia L. and P. latifolia L. (Oleaceae), two Mediterranean shrub species having lignified endocarp

The aim of this study was to determine the germination characteristics of Phillyrea angustifolia L. and P. latifolia L. seeds in order to develop an optimized propagation protocol for Phillyrea species. Seeds of P. angustifolia and P. latifolia were collected from wild plants growing in Cáceres province (CW Spain) and Andalucía (S Spain), respectively. Percentage of water uptake for P. latifolia seeds was calculated. Seeds with and without endocarp were germinated at different constant and alternating temperatures. Seeds without endocarp were soaked in distilled water or gibberellic acid, and then set to germinate. Seeds with endocarp of both species were stratified at 5 ºC for 30 or 90 days and then the endocarp was completely removed from the seeds before they were sowed. Chemical scarification with sulfuric acid and mechanical scarification were tested on P. angustifolia seeds with endocarp. Phillyrea endocarp was permeable to water, since Phillyrea seeds with endocarp imbibed water, but water uptake was faster when the endocarp was removed. Moreover, the encodarp could interfere mechanically in the emergence of the radicle, since seed germination of Phillyrea species was promoted by the complete removal of the lignified endocarp surrounding each seed. Optimal germination temperature for both species was 15 ºC, and lower temperatures produced secondary dormancy. Soaking in distilled water or gibberellic acid did not significantly enhance seed germination. Cold stratification and chemical scarification treatments were detrimental for seed germination. Keywords cold stratification, Phillyrea species, treatments before sowing, seed germination, seed scarification, lignified endocarp

Optimizing seed conservation protocols and cryopreservation at the CRF-INIA genebank to reduce genetic erosion

The CRF-INIA is the Spanish National Centre for Plant Genetic Resources where a duplicate of all seed active collections belonging to the Spanish Network of the National PGR Program should be deposited. First samples date from 1980?s. Nowadays, the long term collection (base collection) comprises approximately 39,000 samples. The CRF-INIA genebank also maintains the largest active collection in Spain, with up to 22.000 accessions, meanly of cereals and grain legumes. At the CRF-INIA genebank the seed conservation protocol follows the FAO/IPGRI recommendations: seed desiccation at 13-15% RH and 20 °C, and storage at -4 or -18 °C, for the active and base collections, respectively. Seed viability monitoring is performed systematically through germination tests. For most species, the current conservation protocol shows good performance (Martín et al. 2014). However, in some plant groups there is an accumulation of samples with low longevity, for which sample regeneration is costly. For example, after 20 or 30 years of storage, some accessions of Brassica ssp., Lactuca sativa or Secale cereale, have shown low seed viability after storage. In some cases, samples with low germination rates might be not only due to low longevity but also to other reasons, such as problems with dormancy interfiering with the germination test performance and low initial quality of the samples. The general aim of this project is to find alternative storage protocols to reduce genetic erosion, present and future, of the conserved material at the CRF-INIA seedbank. Cryoconservation of seeds at different water contents are being tested in species with low seed longevity and of problematic regeneration (rye, onion and cabbage). Results would be compared to the conventional storage at -18 °C after medium/long term storage

Conductivity test in seeds of different passion flower species

The objective of this work was to evaluate the use of the conductivity test as a means of predicting seed viability in seven Passiflora species: P. alata, P. cincinnata, P. edulis f. edulis, P. edulis f. flavicarpa, P. morifolia, P. mucronata, and P. nitida. Conductivity of non?desiccated (control), desiccated, and non?desiccated cryopreserved seeds was determined and related to their germination percentage. The obtained results suggest that the electrical conductivity test has potential as a germination predictor for P. edulis f. flavicarpa seed lots, but not for the other tested species. Index terms: Passiflora, seed cryopreservation, seed desiccation, seed viability

Teste de condutividade em sementes de diferentes espécies de maracujá

The objective of this work was to evaluate the use of the conductivity test as a means of predicting seed viability in seven Passiflora species: P. alata, P. cincinnata, P. edulis f. edulis, P. edulis f. flavicarpa, P. morifolia, P. mucronata, and P. nitida. Conductivity of non‑desiccated (control), desiccated, and non‑desiccated cryopreserved seeds was determined and related to their germination percentage. The obtained results suggest that the electrical conductivity test has potential as a germination predictor for P. edulis f. flavicarpa seed lots, but not for the other tested species.O objetivo deste trabalho foi avaliar o uso do teste de condutividade como meio de predição da viabilidade de sementes de sete espécies de Passiflora: P. alata, P. cincinnata, P. edulis f. edulis, P. edulis f. flavicarpa, P. morifolia, P. mucronata e P. nitida. A condutividade de sementes não dessecadas (controle), dessecadas e não dessecadas criopreservadas foi determinada e relacionada ao seu percentual de germinação. Os resultados obtidos sugerem que o teste de condutividade elétrica tem potencial como preditor de germinação para os lotes de sementes de P. edulis f. flavicarpa, mas não para os das outras espécies testadas

Indirect sinus lift without bone graft material: systematic review and meta-analysis

A systematic literature review and a meta-analysis of indirect sinus lift without the use of bone graft material was performed. A PubMed search was made from January 2005 to January 2012 with keywords: “sinus lift” , “osteo-tome” , “graft” and “maxillary sinus elevation” . The inclusion criteria were: maxillary sinus lift technique with osteotomes with a minimum follow-up period of 5 months after surgery without bone graft material. 11 articles were included. The mean gain in residual crestal bone height after maxillary sinus lift without bone graft material was 3,43 mm ± 0,09 (2,5 mm – 4,4 mm). The survival rate ranged from 94% to 100%. Placement of implants with sinus lift without bone graft material, is a valid surgical technique to gain residual crestal height and placed implants in an atrophic posterior maxillary with a crestal height from 5 to 9 m

Manejo en bancos de germoplasma: estrategia para la ruptura de dormición de semillas de leguminosas

La gestión de los bancos de germoplasma mediante la conservación de semillas se encuentra en ocasiones con dificultades técnicas que pueden llegar a hacer su tarea poco eficiente. Una de esas dificultades puede ser el llevar a cabo los ensayos de viabilidad de las semillas de forma que los resultados se acerquen lo más posible a la verdadera situación de los lotes estudiados. Este aspecto tiene especial importancia en aquellos casos en los que las semillas presentan dormición. Una característica de las semillas de especies de la familia Fabaceae es presentar cubiertas duras. En estos casos la estrategia a aplicar se basa en utilizar tratamientos de escarificación. Sin embargo, en ocasiones, la variabilidad dentro de un lote de semillas y entre lotes (por ejemplo distintas poblaciones de una misma especie) puede ser muy elevada. El objetivo de este trabajo fue estudiar la variabilidad de la dureza de las cubiertas seminales entre cuatro poblaciones de cada una de estas especies: Medicago polymorpha, Trifolium glomeratum y T. subterraneum. Estas especies presentan además semillas de muy pequeño tamaño que dificultan los tratamientos de escarificación. Se utilizaron diversos tratamientos de escarificación que incluían el lijado de las semillas y tratamientos térmicos (frío, calor o cambios bruscos de temperatura). Los mejores tratamientos variaron con las especies y se pudo determinar aquellos que dieron los mejores resultados en las cuatro poblaciones estudiadas, de forma que la germinación aumentó desde un 0-10 % de las semillas control a 84-100 % en las escarificadas. Mediante el equipo Texture Analyzer TAXTPLUS se midió la dureza de las semillas, en relación a su resistencia a la rotura. Se observó una gran variabilidad dentro de cada población y entre poblaciones. La contribución en la reducción de la dureza de las cubiertas del mejor tratamiento de escarificación varió entre especies y entre poblaciones. Se discute la utilidad del estudio previo de la dureza de las semillas para determinar el mejor tratamiento a emplear. Agradecimientos: Proyecto RF2012-00014-C02-0

Inter-population variation in germination characteristics of "Plantago lanceolata" seeds: effects of temperature, osmotic stress and salinity

Plantago lanceolata is a perennial herbaceous plant widely distributed throughout the Mediterranean region. Variation in germination requirements and tolerance to osmotic stress and salinity were tested using seeds from two wild populations. Germination experiments were conducted under controlled conditions at constant (15, 20 and 25ºC) and alternating (20/10 and 25/15ºC) temperatures, and under a 16 h/8 h light/dark photoperiod. Seeds of both populations were non-dormant and incubation temperature significantly affected the final germination percentage and germination rate. Germination percentages ranged from 27 to 85% for the different temperatures and populations. Significant inter-population variation was found for the germination percentages reached at alternate temperature regimes. To determine the effect of osmotic stress and salinity, four polyethylene glycol (PEG 6000: 10, 20, 30 and 40% w/v) and four NaCl concentrations (50, 100, 200 and 300 mmol·L-1) were tested. Seed germination significantly decreased with increasing in PEG and NaCl concentration. Seed germination recovery when they were transferred to distilled water after PEG or salinity treatments was variable depending on population, suggesting that P. lanceolata seeds are moderately tolerant to osmotic and salt stresses at germination stage

Estudio para la implantación de Programas en Inglés en los títulos de grado de la ETSI Agrónomos de la Universidad Politécnica de Madrid

Universities are offering more and more courses and programmes in an additional language. At HEPCLIL, therefore, we would like to debate the methodological im - plications of these changes, giving voice to practical classroom experiences and initiatives. We would also like to act as a platform for cutting-edge research on CLIL in higher education. What impact does teaching in an additional language have on content or language learning? What are the effects on teachers and stu - dents in higher education