The effect of temperature, substrate, light, oxygen availability and burial depth on Ottelia alismoides seed germination

• 25–30 °C was favorable for seed germination of Ottelia alismoides.
• Seed germination percentage is significantly higher in mud than that in sand.
• Oxygen availability had no significant effect on seed germination.
• Germination occurred only in the light.
• Burial significantly inhibited seed germination.

Populations of Ottelia alismoides (Linn.) Pers. in China appear to decrease rapidly. Recruitment and expansion of O. alismoides depends solely on sexual reproduction. This makes the understanding of its germination requirements vital for conservation and management. We conducted laboratory studies to investigate the effects of five environmental variables (temperature, substratum, oxygen, light availability, and burial depth) on the seed germination of O. alismoides. Our results showed that a temperature range of 25–30 °C was favorable for seed germination. Seeds germinated well in mud and variations in oxygen availability had no significant effect on this. Germination occurred only in the light at all tested temperatures. Burial significantly inhibited seed germination. These results indicate that burial and light availability could be a limiting factor for O. alismoides seed germination in natural freshwaters, and lightly stirring up the sediment to bring seeds to the surface will be beneficial to the seed germination.