Table 2.
Photosynthetic parameter of maize seedlings
| |
|
Low temperature |
Low nitrogen |
Low phosphorus |
||||||
|---|---|---|---|---|---|---|---|---|---|---|
| PS parameter | Unit | Control T | Cold | % | Control N | Low N | % | Control P | Low P | % |
|
assimilation |
μmol m-2 s-1 |
8.00 |
8.92 |
111.51 |
8.11 |
5.46 |
67.33 |
8.11 |
4.06 |
49.98 |
| |
|
(±1.29) |
(±1.20) |
|
(±1.07) |
(±1.41) |
|
(±1.07) |
(±1.39) |
|
|
conductance |
mmol m-2 s-1 |
74.71 |
90.25 |
120.79 |
47.19 |
32.58 |
69.04 |
47.19 |
47.19 |
99.99 |
| |
|
(±10.11) |
(±16.54) |
|
(±7.68) |
(±7.74) |
|
(±7.68) |
(±6.49) |
|
|
Ci |
ppm |
161.59 |
167.24 |
103.49 |
154.57 |
166.47 |
107.70 |
154.57 |
283.11 |
183.16 |
| |
|
(±12.00) |
(±43.79) |
|
(±19.14) |
(±17.40) |
|
(±19.14) |
(±22.75) |
|
|
PSII efficiency |
|
0.187 |
0.224 |
119.75 |
0.312 |
0.269 |
86.32 |
0.312 |
0.139 |
44.56 |
| (±0.028) | (±0.046) | (±0.028) | (±0.014) | (±0.028) | (±0.030) | |||||
Gas exchange and fluorescence measurements were performed on leaf 4 at day 20 after germination in the cold stress experiment, and on leaf 6 at days 28–30 after germination in the nutrient experiments. Photosynthesis measurements for nutrient deficient leaves were performed on plants which were cultivated in the greenhouse at the same time and the data for control N and P was therefore the same.