arXiv subjects

A. Dupont

Publications and source records attributed to A. Dupont.

2 recordsLinked to original sources

arXiv2025

Breaking seed dormancy in Mediterranean Brassica rapa wild populations: is cold plasma treatment efficient?

Turnip (Brassica rapa) is a native species of the Mediterranean area, spread from northwest France to south Algeria. In this study, dormancy and germination traits were assessed for 61 wild Brassica rapa populations collected across the Mediterranean region. Seed dormancy is a key factor influencing germination and seedling establishment. Three dormancy-breaking methods were compared: gibberellic acid, scarification and cold plasma. The efficiency and selectivity were evaluated through germination ability, time to 10% germination (T10), mean germination time and greenhouse emergence. Five days after imbibition, germination was only 18% for the untreated seeds but 60% for the plasma-treated seeds. Germination also began 24 hours earlier and mean germination time was reduced across most populations. However, there was a limited effect on seedling emergence, which remained around 55% for both untreated and treated samples. Comparative analysis indicates that cold plasma was more effective in alleviating embryo dormancy. In addition, histological and scanning electron microscopy showed that the seed coat differed according to the geographical origin of the populations, with a deeper dormancy in seeds from Sicilian populations.

physics.plasm-ph↗

arXiv2023

Fish evacuate smoothly respecting a social bubble

Crowd movements are observed among different species and on different scales, from insects to mammals, as well as in non-cognitive systems, such as motile cells. When forced to escape through a narrow opening, most terrestrial animals behave like granular materials and clogging events decrease the efficiency of the evacuation. Here, we explore the evacuation behavior of macroscopic, aquatic agents, neon fish, and challenge their gregarious behavior by forcing the school through a constricted passage. Using a statistical analysis method developed for granular matter and applied to crowd evacuation, our results clearly show that, unlike crowds of people or herds of sheep, no clogging occurs at the bottleneck. The fish do not collide and wait for a minimum waiting time between two successive exits, while respecting a social distance. When the constriction becomes similar to or smaller than their social distance, the individual domains defined by this cognitive distance are deformed and fish density increases. We show that the current of escaping fish behaves like a set of deformable 2D-bubbles, their 2D domain, passing through a constriction. Schools of fish show that, by respecting social rules, a crowd of individuals can evacuate without clogging, even in an emergency situation.

physics.bio-ph↗