STAY FOCUSED DESPITE STRESS: PERCEPTION OF ENVIRONMENTAL SIGNALS THAT BREAK SEED DORMANCY IN ECHINOCHLOA CRUS-GALLI SEEDS UNDER HYPOXIC FLOODWATERS

PERALTA OGOREK LL; MOLLARD FPO; ECHEVERRY J; STRIKER GG

Congreso; XVI Congreso Latinoamericaco de Fisiología Vegetal; 2018

Asociación Sociedad Argentina de Fisiología Vegetal

Seedlings have limited resources to tolerate or to escape from submergence. Seed dormancy could be an effective trait to avoid lethalunderwater germination, and defer seedling growth until the post-flooding period. This research aimed at testing potential adaptive dormancyresponses to hypoxic floodwaters in Echinochloa crus-galli seeds. E. crus-galli seeds were 1) submerged under hypoxic floodwaters at differenttemperatures during 15 or 30 days and then, germination was tested while exposing seeds to dormancy-breaking signals (alternatingtemperatures, high nitrates, and light) under drained conditions or 2) exposed to dormancy-breaking signals during hypoxic submergence and their germination was monitored during and after incubation. Hypoxic submergence hindered the induction of secondary dormancy by warm temperatures. Seeds submerged under hypoxic water could sense light through phytochromes. Moreover, seeds remained under phytochrome control during hypoxic submergence and did not break dormancy until normoxic conditions were regained. Only a fraction of seeds (≈35%) could perceive alternating temperatures under hypoxic floodwaters. In conclusion, hypoxic floodwaters interfere with E. crus-galli seed dormancy cycling. Additionally, results indicate that a fraction of E. crus-galli of seeds are able to perceive dormancy breaking signals under hypoxic water and can germinate immediately after aerobic conditions are restored.