Optimal growth conditions of Azolla pinnata R. Brown: impacts of light intensity, nitrogen addition, pH control, and humidity
Dataset for a journal article published on Plants 2022, vol. 11, no. 1048.
Nitrogen pollution from agriculture, a major challenge facing our society today. Biological nitrogen fixation is key to combat damages caused by synthetic nitrogen. The Azolla spp. species are ideal candidates for fast nitrogen fixation. This study aims to investigate the optimal growth conditions of Azolla pinnata R. Brown. The growth conditions investigated were the growth medium type and strength, light intensity, nitrogen presence/absence in the medium, pH control, and humidity. Higher light intensities increased plants growth by, on average, 32 %. The highest humidity (90 %) yielded higher growth rate values than the lower humidity values (60 % and 75 %). The presence of nitrogen in the medium had no significant effect on the growth rate of the plants. pH control was critical under fast growth conditions of high light intensity and high humidity, and this reduced algal growth (from visual observation). The optimal growth rate achieved was 0.321 day-1, a doubling time of 2.16 days. This was achieved by using a 15 % strength of Hoagland’s medium, high light intensity (20 000 lx), nitrogen present, and pH control at 90 % humidity. These optimised conditions offer an improvement to existing Azolla pinnata-phytoremediation systems and aids in the fight against synthetic nitrogen pollution.