Effect of pericarp removal on buckwheat seed respiration and germination under submerged conditions

ABSTRACTExcessive soil moisture (ESM) is a critical factor limiting the productivity of buckwheat (Fagopyrum esculentum Moench) because ESM inhibits its germination. This study investigated the effects of pericarp and seed respiration on reduced buckwheat germination caused by submergence. Seeds were submerged prior to germination testing under aerobic conditions. The effects of days of submergence treatment and pericarp removal on germination percentage were significant. The germination percentage in the 3-day submergence treatment was low in seeds with pericarp (P+) but was significantly improved in seeds without pericarp (P−). Pericarp removal also improved the germination percentage of non-submerged seeds. Pericarp thickness and pericarp/seed dry weight ratio (PWR) were not significantly correlated with the germination percentage in 3-day submerged P+. However, both were significantly negatively correlated with the germination percentage in 1-day submerged P+. Seed respiration rate in water, measured on seeds not submerged before measurement, was significantly higher in P− than in P+; that of P− increased with time, while that of P+ showed a decreasing trend with time beyond the first 24 h. Seed respiration rate during the first 24 h was significantly negatively correlated with germination percentage in 3-day submerged P+. A negative influence of pericarp thickness and PWR on the seed respiration rate of P+ during the first 24 h was suggested. Suppressed seed respiration by the pericarp is probably a cause of inhibited buckwheat germination under ESM conditions.