Low concentration of nitrate increases germination velocity of intact seeds of Nepeta micrantha in the first few days of germination

Nitrate promotes seed germination at low concentrations in many plant species. Meanwhile, mucilage plays a crucial role in germination by regulating seed responses to different environmental factors. This study investigated the effect of nitrate and mucilage on seed germination of the ephemeral plant Nepeta micrantha. Nitrate had distinct effects on intact and demucilaged seeds. Specifically, low nitrate concentration significantly increased the germination velocity of intact seeds, but decreased that of demucilaged seeds in the first few days. The addition of nitrate did not significantly affect the final germination percentage and germination index of intact and demucilaged seeds within the 20-day germination period, except for the demucilaged seeds treated with 0.01 mmol L-1 KNO3. This study suggests that nitrate and mucilage have a positive impact on germination of N. micrantha seeds in harsh environments.