Search results for "Germination"
showing 10 items of 251 documents
Effect of water content and temperature on seed longevity of seven Brassicaceae species after 5 years of storage.
2014
Maximising seed longevity is crucial for genetic resource preservation and longevity of orthodox seeds is determined by environmental conditions (water content and temperature). The effect of water content (down to 0.01 g·H₂O·g(-1) ) on seed viability was studied at different temperatures for a 5-year storage period in taxonomically related species. Seeds of seven Brassicaceae species (Brassica repanda, Eruca vesicaria, Malcolmia littorea, Moricandia arvensis, Rorippa nasturtium-aquaticum, Sinapis alba, Sisymbrium runcinatum) were stored at 48 environments comprising a combination of eight water contents, from 0.21 to 0.01 g·H₂O·g(-1) DW and six temperatures (45, 35, 20, 5, -25, -170 °C). S…
Opportunistic Germination Behaviour of Gypsophila (Caryophyllaceae) in Two Priority Habitats from Semi-arid Mediterranean Steppes
2011
Gypsophila tomentosa and G. struthium are closely related species, characteristic of two European priority habitats, salt and gypsum inland steppes, respectively. Germination strategies of the two taxa were investigated in plants from two nearby populations, growing under the same climatic conditions but on different types of soil, and belonging to different plant communities. Their germination patterns were studied at five constant temperatures in darkness: 5oC, 10oC, 15oC, 20oC and 25oC, and the base temperature and the thermal time requirement were calculated. As the distribution area of both species is subjected to a Mediterranean continental climate with significant differences between…
The role of light in the emergence of weeds: using Camelina microcarpa as an example
2015
When modelling the emergence of weeds, two main factors are considered that condition this process: temperature and soil moisture. Optimum temperature is necessary for metabolic processes that generate energy for growth, while turgor pressure is necessary for root and shoot elongation which eventually leads to seedling emergence from the soil. Most emergence models do not usually consider light as a residual factor, but it could have an important role as it can alter directly or indirectly the dormancy and germination of seeds. In this paper, inclusion of light as an additional factor to photoperiod and radiation in emergence models is explored and compared with the classical hydrothermal t…
Assessing Effects of Temperature Change on Four Limonium Species from Threatened Mediterranean Salt-Affected Habitats
2018
[EN] Evaluation of tolerance to temperatures in the germination stage is an important tool to foresee the possible effect of global warming. Moreover, establishing germination protocols for endemic and threatened species is most interesting for restoration and management plans that focus on habitat conservation. Seed germination was analysed in four species of the genus Limonium (L. virgatum, L. narbonense, L. girardianum and L. santapolense) growing in two saline habitats on the eastern coast of the Iberian Peninsula. The study aim was to compare responses of seed germination to different temperature regimes. Seeds were collected in two protected areas, `L¿Albufera de Valencia¿ (province o…
Seed germination reports for coastal sand dune species from Sicily
2019
This study investigated seed germination in nine psammophilous species occurring in Sicilian sand dunes, some of which, such as Muscari gussonei, Launaea resedifolia and Pancratium maritimum, are endemic and/or rare and very scattered in the area. Different germination protocols were tested for one or more populations and the best germination results per species are provided, reporting experimental conditions and specific comments on the germination behaviour.
Modélisation des effets des systèmes de culture sur la levée des adventices à partir de relations fonctionnelles utilisant les traits des espèces
2008
The aim of the Ph. D. Was to adapt the monospecific model ALOMYSYS to a multi-specific flora, in order to predict the effects of cropping systems on the timing and quantities of emerging weed seedlings. Determining the parameters for each additional species is unfeasible. A second objective was thus to estimate the parameters from easily measurable species traits. After having performed a large literature analysis, 18 weeds were studied for the processes involved into the seedbank dynamics and emergence. The seed mortality in the soil could not be related with species traits and can be parameterised with literature data. A generic and simplified formalism represens the seasonal variations o…
Reactive oxygen species release, vitamin E, fatty acid and phytosterol contents of artificially aged radish (Raphanus sativus L.) seeds during germin…
2012
Abstract Seeds of Raphanus sativus L. subjected to accelerated ageing were investigated for reactive oxygen species (ROS) release and for content of vitamin E (tocopherol, TOC, and tocotrienol, TOC-3), fatty acids and phytosterols in seed coats, cotyledons and embryonic axes during germination. In unaged seeds, ROS release occurred mainly in seed coats of non-imbibed seeds and in seedlings (48 h of imbibition). TOC and TOC-3 were mainly represented by the c-isoform, abundant in embryonic axes. Fatty acids were mainly found in cotyledons. In seed coat and embryonic axis, phytosterols consisted mainly of sitosterols. The effects of ageing were mainly visible in embryonic axes at 48 h of imbib…
Maitrise de la fermentation butyrique par la microflore lactique réductrice
2018
Clostridium tyrobutyricum, bactérie anaérobie stricte, endosporulée, est à l’origine de l’apparition du défaut appelé «gonflement tardif » lors de l’étape d’affinage de nombreux fromages à pâtes pressées non cuites et cuites. Selon d’Incecco et al. (2018), elle passerait de l’état spore à un état de cellule végétative à la fin de l’étape d’acidification. Par ailleurs dans le projet ANR FoodREDOX, il a été montré qu’un ensemencement dans le lait d’une microflore abaissant le potentiel d’oxydoréduction, ralentirait la consommation de lactates et la production de butyrate par C. tyrobutyricum lors de l’affinage des fromages. Ainsi, connaître et comprendre les mécanismes de germination, sporula…
Dianthus superbus as a critically endangered species in Latvia: evaluation of its growth conditions and conservation possibilities
2021
Abstract Dianthus superbus is one of the most endangered species in Latvia and is on the verge of local extinction. Therefore, the aim of this study was to inventory previously identified populations of D. superbus in Latvia and to develop activities to conserve this species in accordance with the results obtained in situ. Expeditions on 18 previously documented locations, according to the data of Nature Conservation Agency, revealed only three existing D. superbus localities in Latvia with a significant number of specimens located in the Latgale region near Silenieki. In 2020, for the first time, two more new D. superbus localities were found in the vicinity of these three approved locatio…
Effects of seed production and storage conditions on blackgrass (Alopecurus myosuroides) germination and shoot elongation
2003
Abstract Blackgrass is a common winter annual grass weed in autumn-sown crop rotations in Atlantic European countries. Control with a minimum amount of herbicides in integrated cropping systems would be facilitated by modeling the effect of cropping systems on its demography. To develop the submodel relating weed seed bank to emerged seedlings, laboratory experiments were conducted to analyze and quantify seed germination and shoot elongation. These processes were studied as a function of environmental conditions during seed production (nitrogen availability, water deficit, plant density, and crop) and of seed characteristics (seed weight, harvest date, storage length, and dry-stored/soil-b…