Table 3.
Growth and nitrogen fixation of wild-type and sunn M. truncatula plants. Data are given per plant as means of 6 replicates. Specific N2-fixation was calculated from the N increment in plants (N-free nutrient solution) and the number of nodules at the end of the experimental period.
| Parameter | Wild-type | Mtsunn | ||
|---|---|---|---|---|
|
|
|
|||
| 400 ppm CO2 | 1200 ppm CO2 | 400 ppm CO2 | 1200 ppm CO2 | |
| Shoot [g DM] | 3.4 | 4.1 * | 2.7 | 3.4 * |
| Root/Nodules [g DM] | 1 | 1.7 | 0.6 | 1.3 * |
| Nodule Number per plant | 186 | 287 | 798 | 1004 |
| Specific N2 fixation [μg N·day−1·nodule−1] | 1.45 | 0.93 * | 0.26 | 0.31 |
*
indicates a statistically significant difference when compared to plants grown at 400 ppm CO2 around shoots (t-test, p < 0.05, n = 6).
Plants were grown for 8 weeks at ambient CO2. Subsequently the treatment and control conditions were maintained for three weeks. The experiment was done under greenhouse conditions with natural light and the plants enclosed in a plexiglass chamber with regulated atmosphere.