Cell quotas and stoichiometry
The C, N, and P cell quotas in Scenedesmus varied significantly among the culture media from different types of leaf litter leachates in the control treatment (Fig. 3; F = 33.24, p < 0.001 for C quota; F = 40.27, p < 0.001 for N quota; F = 16.36, p < 0.001 for P quota). The micronutrient amendment of the culture media had a significant negative effect on the C cell quota in the leaf litter leachates of oak and Japanese hemlock, and a significant positive effect was detected in the leaf litter leachate of hinoki cypress (Fig. 3a). The micronutrient amendment had a negative effect on the N cell quota only in the leaf litter leachate of Japanese hemlock (Fig. 3b). Similarly, the negative effect of the micronutrient amendment on the P cell quota was detected in the leaf litter leachate of Japanese hemlock, and a significant positive effect was found in the leaf litter leachates of Japanese red pine and hinoki cypress (species ID 9 and 11; Fig. 3c).
The molar C:N cell quota ratios of Scenedesmus varied from 6.6:1 to 21:1, and was less than 12:1 except for Japanese maple, oak, Japanese hemlock, Japanese red pine, and Japanese larch (species ID 1, 4, 7, 9, 10 in Fig. 4a). The molar C:P ratios of the algae varied from 106:1 to 300:1, except for cells in grown in the culture medium prepared from the leaf litter leachate of Japanese maple (species ID 1), which reached C:P = 600:1 (Fig. 4b). The molar N:P ratio of the algae was distributed between 10:1 and 30:1, and was lower than 16:1 in the leaf litter leachates of Siebold’s beech, Japanese elm, Japanese red pine, and hinoki cypress (species ID 5, 6, 9, 11 in Fig. 4c).