To germinate or not to germinate : a question of dormancy relief not germination stimulation

A common understanding of the control of germination through dormancy is essential for effective communication between seed scientists whether they are ecologists, physiologists or molecular biologists. Vleeshouwers et al. (1995) realized that barriers between disciplines limited progress and through insightful conclusions in their paper ‘Redefining seed dormancy: an attempt to integrate physiology and ecology’, they did much to overcome these barriers at that time. However, times move on, understanding develops, and now there is a case for ‘Redefining seed dormancy as an integration of physiology, ecology and molecular biology’. Finch-Savage and Leubner-Metzger (2006) had this in mind when they extended and re-interpreted the definition of dormancy proposed by Vleeshouwers et al. (1995), by considering dormancy as a having a number of layers that must be removed, with the final layer of dormancy being synonymous with the stimulation/induction of germination

Optimization of timing of next-generation emergence in Amaranthus hybridus is determined via modulation of seed dormancy by the maternal environment

The timing of emergence of weed species has critical ecological and agronomical implications. In several species, emergence patterns largely depend on the level of dormancy of the seedbank, which is modulated by specific environmental factors. In addition, environmental conditions during seed maturation on the mother plant can have marked effects on the dormancy level at the time of seed dispersal. Hence, the maternal environment has been suggested to affect seedbank dormancy dynamics and subsequent emergence; however, this modulation has not been adequately examined under field conditions, and the mechanisms involved are only partly understood. Combining laboratory and field experiments with population-based models, we investigated how dormancy level and emergence in the field are affected by the sowing date and photoperiod experienced by the mother plant in Amaranthus hybridus, a troublesome weed worldwide. The results showed that an earlier sowing date and a longer photoperiod enhanced the level of dormancy by increasing the dormancy imposed by both the embryo and the seed coat. However, this did not affect the timing and extent of emergence in the field; on the contrary, the variations in dormancy level contributed to synchronizing the emergence of the next generation of plants with the time period that maximized population fitness. Our results largely correspond with effects previously observed in other species such as Polygonum aviculare and Arabidopsis, suggesting a common effect exists within different species.Fil: Fernández Farnocchia, Rocio Belen. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Producción Vegetal. Cátedra de Cultivos Industriales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: Benech-Arnold, Roberto Luis. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Producción Vegetal. Cátedra de Cultivos Industriales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: Mantese, Anita Ida. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Recursos Naturales y Ambiente; ArgentinaFil: Batlla, Diego. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentin

Seed dormancy responses to temperature relate to Nothofagus species distribution and determine temporal patterns of germination across altitudes in Patagonia

507-520. Seeds integrate environmental cues that modulate their dormancy and germination. Although many mechanisms have been identified in laboratory experiments, their contribution to germination dynamics in existing communities and their involvement in defining species habitats remain elusive. . By coupling mathematical models with ecological data we investigated the contribution of seed temperature responses to the dynamics of germination of three Nothofagus species that are sharply distributed across different altitudes in the Patagonian Andes. . Seed responsiveness to temperature of the three Nothofagus species was linked to the thermal characteristics of their preferred ecological niche. In their natural distribution range, there was overlap in the timing of germination of the species, which was restricted to mid - spring. By contrast, outside their species distribution range, germination was temporally uncoupled with altitude. This phenomenon was described mathematically by the interplay between interspecific differences in seed population thermal parameters and the range in soil thermic environments across different altitudes. . The observed interspecific variations in seed responsiveness to temperature and its environmental regulation, constitute a major determinant of the dynamics of Nothofagus germination across elevations. This phenomenon likely contributes to the maintenance of patterns of species abundance across altitude by placing germinated seeds in a favorable environment for plant growth

Seed dormancy responses to temperature relate to Nothofagus species distribution and determine temporal patterns of germination across altitudes in Patagonia

Seeds integrate environmental cues that modulate their dormancy and germination. Although many mechanisms have been identified in laboratory experiments, their contribution to germination dynamics in existing communities and their involvement in defining species habitats remain elusive. By coupling mathematical models with ecological data we investigated the contribution of seed temperature responses to the dynamics of germination of three Nothofagus species that are sharply distributed across different altitudes in the Patagonian Andes. Seed responsiveness to temperature of the three Nothofagus species was linked to the thermal characteristics of their preferred ecological niche. In their natural distribution range, there was overlap in the timing of germination of the species, which was restricted to mid-spring. By contrast, outside their species distribution range, germination was temporally uncoupled with altitude. This phenomenon was described mathematically by the interplay between interspecific differences in seed population thermal parameters and the range in soil thermic environments across different altitudes. The observed interspecific variations in seed responsiveness to temperature and its environmental regulation, constitute a major determinant of the dynamics of Nothofagus germination across elevations. This phenomenon likely contributes to the maintenance of patterns of species abundance across altitude by placing germinated seeds in a favorable environment for plant growth.Fil: Arana, María Verónica. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Gonzalez Polo, Marina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Instituto de Investigación En Biodiversidad y Medioambiente; Argentina. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche; ArgentinaFil: Martinez Meier, Alejandro. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche; ArgentinaFil: Gallo, Leonardo Ariel. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche; ArgentinaFil: Benech-arnold, Roberto Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: Sanchez, Rodolfo Augusto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas A la Agricultura; ArgentinaFil: Batlla, Diego. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentin

Cuando la clave es integrar : introducción al desarrollo de grupos de comportamiento de dormición de malezas en cultivos agrícolas

La versión impresa del vol. 35 (2015) publicó juntos los nos. 1 y 2.p.153-169La intensificación agrícola ha generado la aparición de malezas de difícil control, tanto por cambios en su abundancia, como por el surgimiento de genotipos tolerantes o resistentes a herbicidas. Por ello es importante desarrollar aproximaciones analíticas basadas en la biología de las malezas que permitan predecir cambios florísticos ante diferentes escenarios ambientales. Aunque existen descripciones sobre el funcionamiento de ciertas especies en particular, es escaso el desarrollo de aproximaciones que aborden la predicción del enmalezamiento de manera mecanística. Este trabajo plantea un marco teórico novedoso para el estudio del proceso de enmalezamiento a través del estudio de los efectos de distintos filtros ambientales sobre el riesgo de salida de dormición de propágulos en campos agrícolas, aspecto clave para entender el riesgo de establecimiento de malezas en estos sitios. Para ello se describe la clasificación de especies de malezas en grupos de comportamiento de dormición (GCD), y se describe de manera cualitativa la influencia de distintos filtros ambientales sobre la determinación de ocurrencia de los GCD descriptos. En total se identificaron cuatro GCD de especies anuales y tres de especies perennes, a través de una revisión de 150 trabajos de la literatura. La aproximación teórica descripta en este trabajo ayuda a sistematizar de manera más eficiente el abordaje del problema del enmalezamiento, reduciendo su complejidad basándose en el uso de estrategias funcionales en lugar de las identidades de las especies

Seed dormancy responses to temperature relate to Nothofagus species distribution and determine temporal patterns of germination across altitudes in Patagonia

Seeds integrate environmental cues that modulate their dormancy and germination.Although many mechanisms have been identified in laboratory experiments, their contribu-tion to germination dynamics in existing communities and their involvement in definingspecies habitats remain elusive.By coupling mathematical models with ecological data we investigated the contribution ofseed temperature responses to the dynamics of germination of three Nothofagus species thatare sharply distributed across different altitudes in the Patagonian Andes.Seed responsiveness to temperature of the three Nothofagus species was linked to the ther-mal characteristics of their preferred ecological niche. In their natural distribution range, therewas overlap in the timing of germination of the species, which was restricted to mid-spring.By contrast, outside their species distribution range, germination was temporally uncoupledwith altitude. This phenomenon was described mathematically by the interplay between inter-specific differences in seed population thermal parameters and the range in soil thermic envi-ronments across different altitudes.The observed interspecific variations in seed responsiveness to temperature and its environ-mental regulation, constitute a major determinant of the dynamics of Nothofagus germinationacross elevations. This phenomenon likely contributes to the maintenance of patterns ofspecies abundance across altitude by placing germinated seeds in a favorable environment forplant growthFil: Arana, Maria Veronica. Instituto Nacional de Tecnologia Agropecuaria. Centro Reg.patagonia Norte. Estacion Exptal.agrop.s.c.de Bariloche; ArgentinaFil: Gonzalez Polo, Marina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Instituto de Investigación en Biodiversidad y Medioambiente; ArgentinaFil: Martinez Meier, Alehandro. Instituto Nacional de Tecnologia Agropecuaria. Centro Reg.patagonia Norte. Estacion Exptal.agrop.s.c.de Bariloche; ArgentinaFil: Gallo, Leonardo. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Patagonia Norte. Estación Experimental Agropecuaria San Carlos de Bariloche; ArgentinaFil: Benech-arnold, Roberto Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: Sánchez, Roberto Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: Batlla, Diego. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentin

Efecto de la temperatura, el potencial hídrico y su interacción sobre la germinación de semillas de lapacho rosado (Handroanthus impetiginosus)

PosterUno de los procesos más importantes del ciclo de vida de las plantas es la germinación de las semillas. La temperatura y la disponibilidad de agua son los principales factores ambientales que regulan la germinación de las semillas, afectando tanto el porcentaje final como el tiempo de germinación (Baskin y Baskin, 2014). Para el lapacho rosado (Handroanthus impetiginosus) se ha indicado que las semillas pueden germinar en un amplio rango de temperaturas (15- 40°C) con una temperatura óptima alrededor de los 32°C y que son sensibles al estrés hídrico (hasta -0,6M o -0.8 Mpa; Pastrana-Ignes, 2020). Sin embargo, se ha indicado que ambos factores actuarían de manera independiente sobre la germinación de las semillas, aunque esta interacción ha sido evaluada solo a 25 y 30°C (Valdovinos et al., 2021). El objetivo de este trabajo fue determinar el efecto de la temperatura, potencial hídrico y su interacción sobre la germinación de semillas de esta especie, considerando un amplio rango de temperaturas y potenciales hídricos.Instituto de Recursos BiológicosFil: Rivero, María Victoria. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Biológicos. Banco Base de Germoplasma; Argentina.Fil: Malagrina, Gisela. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Biológicos. Banco Base de Germoplasma; Argentina.Fil: Alvarez, Ana Carolina. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Biológicos. Banco Base de Germoplasma; Argentina.Fil: Amarillo, Karina. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Biológicos. Banco Base de Germoplasma; Argentina.Fil: Fornes, Luis. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Famaillá; ArgentinaFil: Suhring, Silvia. Universidad Nacional de Salta; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Batlla, Diego. Universidad de Buenos Aires. Facultad de Agronomía. Catedra de Cerealicultura; ArgentinaFil: Galindez, Guadalupe. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Laboratorio de Investigaciones Botánicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Decision Support Systems for Weed Management

Editors: Guillermo R. Chantre, José L. González-Andújar.Weed management Decision Support Systems (DSS) are increasingly important computer-based tools for modern agriculture. Nowadays, extensive agriculture has become highly dependent on external inputs and both economic costs, as well the negative environmental impact of agricultural activities, demands knowledge-based technology for the optimization and protection of non-renewable resources. In this context, weed management strategies should aim to maximize economic profit by preserving and enhancing agricultural systems. Although previous contributions focusing on weed biology and weed management provide valuable insight on many aspects of weed species ecology and practical guides for weed control, no attempts have been made to highlight the forthcoming importance of DSS in weed management. This book is a first attempt to integrate 'concepts and practice' providing a novel guide to the state-of-art of DSS and the future prospects which hopefully would be of interest to higher-level students, academics and professionals in related areas

After-ripening alters the gene expression pattern of oxidases involved in the ethylene and gibberellin pathways during early imbibition of Sisymbrium officinale L. seeds

After-ripening (AR) in Sisymbrium officinale seeds altered SoACS7, SoACO2, SoGA20ox2, SoGA3ox2, and SoGA2ox6 gene expression. Except for SoGA20ox2 expression, which sharply diminished, the expression of the other genes rose during development, particularly that of SoACS7. In contrast, only the SoACO2 and SoGA2ox6 transcripts increased with seed desiccation; the others decreased. AR increased the SoGA3ox2 transcript in dry seed, but dramatically decreased the SoACS7 transcript. At the onset of imbibition, AR inhibited SoACS7 and SoACO2 expression and stimulated that of SoGA20ox2, SoGA3ox2, and SoGA2ox6, demonstrating that the participation of ethylene (ET) and gibberellins (GAs) differs in after-ripened and non-after-ripened seeds. The inhibition of SoACO2 expression in the presence of GA4+7, paclobutrazol (PB), inhibitors of ET synthesis and signalling (IESS), and notably ET+GA4+7 indicated ET–GA cross-talk in non-after-ripened seeds. A positive effect of AR in reversing this inhibition was found. The idea of ET–GA cross-talk is also supported by the effect of ET on SoGA3ox2 expression, notably induced by the AR process. In contrast, SoGA20ox2 expression did not appear to be susceptible to AR. SoGA2ox6 expression, poorly known in seeds, suggests that AR prompted an up-regulation under all treatments studied, whereas in non-after-ripened seeds expression was down-regulated. On the other hand, the β-mannanase (MAN) activity dramatically increased in dry after-ripened seed, being significantly boosted by ET. The absence of MAN inhibition by IESS suggests that although ET seems to be one of the factors controlling MAN, its presence did not appear to be essential. GA4+7 only increased MAN in seeds wich were after-ripened. Here, it is proposed that ET and GAs participate actively in establishing the AR process