Table 1.
Means (±SE) and F-values for observed photosynthetic rate under ambient light and [CO2] (A), water-use efficiency (WUE), and for leaf water potential (ΨL) at pre-dawn (PD) and mid-day (MD), measured on 1-, 2-, and 3-year-old cohorts of intermediate wheatgrass (Thinopyrum intermedium) in a 2013 study at Kellogg Biological Station (Hickory Corners, MI)
Means for the two older cohorts are compared against first-year plants (n=6 for first- and third-year cohorts, n=4 for second-year).
| A (μmol m −2 s −1) | IWUE (mmol mol−1) | A (μmol m −2 s −1) | IWUE (mmol mol−1) | ΨL,PD (MPa) | ΨL,MD (MPa) | |
|---|---|---|---|---|---|---|
| Date | 22 April | 22 April | 12 July | 12 July | 12 July | July 12 |
| Wheatgrass (1-year-old) | 26.6±4.5 | 139.9±19.2 | 37.2±3.4 | 42.9±5.0 | –0.16±0.01 | -0.46±0.06 |
| Wheatgrass (2-year-old) | 26.7±0.9 | 55.6±8.2 | 29.3±2.2 | 43.1±2.7 | –0.24±0.03* | -0.66±0.14 |
| Wheatgrass (3-year-old) | 24.2±1.6 | 72.3±3.7 | 30.7±2.2* | 43.5±7.5 | –0.17±0.02 | -0.81±0.19 |
| Source of variation | ||||||
| Age | 0.04 | 88.93*** | 21.06** | 2.90 | 2.90 | 0.00 |
| Mature cohort age | 0.62 | 7.92* | 2.01 | 0.04 | 6.35 | 0.94 |
*, **, and *** indicate significance at α=0.05, 0.01, and 0.001 respectively.