Figure 4. Average number of seeds per plant.

Average number of seeds per plant depends on the CO₂ concentration (ambient, 365 ppm or enriched, 750 ppm), the condition of inoculation (I: inoculated or NI: not with Pseudomonas fluorescens C7R12) and the developmental stage of Medicago truncatula (Fp, Pf, see text). Data were log-transformed to achieve normality and equal variances respectively tested by Shapiro-Wilk and Bartlett tests. Number of seeds, measured during the second experiment replicate only, was analysed by linear model with condition of inoculation, CO₂ concentration and developmental stage as fixed factors and with their interactions. Standard errors are represented by vertical bars.