Table I.
Effects of Zn deficiency on Zn content, photosynthesis, δ13C value, chlorophyll content, and levels of CA and Rubisco in fully expanded leaves
| Parameter | +Zn | ±Zn | −Zn |
|---|---|---|---|
| Zn content (mg m−2) | 0.51 ± 0.05 | 0.23 ± 0.03 (45) | 0.19 ± 0.04 (37) |
| Specific leaf wt (g m−2) | 19.3 ± 2.0 | 20.2 ± 2.6 (105) | 19.9 ± 3.6 (103) |
| Chlorophyll content (g m−2) | 0.59 ± 0.09 | 0.49 ± 0.15 (82) | 0.45 ± 0.14 (78) |
| Photosynthesis (μmol CO2 m−2 s−1) | 22.9 ± 1.7 | 19.7 ± 3.6 (86) | 20.4 ± 2.3 (89) |
| Soluble protein (g m−2) | 6.5 ± 0.3 | 7.7 ± 0.3 (118) | 7.5 ± 0.2 (116) |
| CA activity (× 103 units m−2) | 473 ± 57 | 126 ± 23 (27) | 68 ± 36 (14) |
| Rubisco content (g m−2) | 3.5 ± 0.3 | 4.3 ± 0.3 (126) | 4.8 ± 0.4 (139) |
| Rubisco activity (μmol CO2 m−2 s−1) | 29.4 ± 2.6 | 23.5 ± 4.3 (80) | 26.3 ± 5.2 (89) |
| δ13C value (‰) | −25.83 ± 0.24 | −24.05 ± 1.27 | −23.55 ± 1.91 |
Values are expressed as means ± se; n = 18 except for the δ13C value (n = 3). Numbers in parentheses are percentages relative to values for +Zn plants.