Ecophysiology of seedling recruitment during floods: The case of Echinochloa colona, a harmful arable weed of extensive crops

JULIANA ECHEVERRY HOLGUÍN; MARÍA CREPY; GUSTAVO STRIKER; FEDERICO MOLLARD

ROSARIO

Conferencia; RAFV Conference 2023 XXXIV Argentinian Meeting of Plant Physiology; 2023

In the Pampas, the transition of floodplains to agriculture has facilitated the encroachment of hydrophyte weeds. Our objectives were: (i) to investigate whether flooding controls or promotes the spread of Echinochloa colona and, (ii) to explore environmental cues that can stimulate underwater germination of its seeds. To address (i), we conducted two flooding experiments (flood level: 10-15 cm) in soil mesocosms obtained from a floodplain crop in the Province of Buenos Aires (corn/wheat-soybean/sunflower rotation) and taken to FAUBA experimental field. We simulated the seasonal decrease in floodwater levels throughout the growing season by draining mesocosms monthly starting from winter (year 1). In year 2, we simulated intermittent flood and drainage conditions of varying monthly durations. Experiments included mesocosms constantly flooded and drained to field capacity (controls). We weekly monitored seedlings emergence and recorded established plants, as well as their biomass and fecundity. Significant interactions between treatment and time were observed for emergence in both years (p