Table II
Gas exchange measurements in two contrasting P. cathayana populations exposed to different UV-B levels under well-watered or drought-stressed conditions.
Population | Treatment | A (μmol m−2 s−1) | gs (μmol m−2 s−1) | E (mmol m−2 s−1) | PNUE (μmol g−1 N s−1) |
---|---|---|---|---|---|
JZ | W | 17.23 ± 0.19e | 0.75 ± 0.02d | 5.75 ± 0.07f | 7.32 ± 0.55c |
WU | 13.78 ± 0.05d | 0.64 ± 0.01c | 3.88 ± 0.04c | 4.91 ± 0.43b | |
D | 12.72 ± 0.11c | 0.38 ± 0.05b | 2.53 ± 0.20b | 4.69 ± 0.11b | |
DU | 5.88 ± 0.28a | 0.09 ± 0.00a | 0.93 ± 0.04a | 2.65 ± 0.36a | |
DT | W | 23.35 ± 0.33g | 0.82 ± 0.00e | 5.78 ± 0.05f | 13.17 ± 0.95c |
WU | 21.55 ± 0.07f | 0.60 ± 0.01c | 5.00 ± 0.04e | 9.68 ± 0.22b | |
D | 21.3 ± 0.21f | 0.64 ± 0.02c | 4.13 ± 0.07d | 9.76 ± 0.34b | |
DU | 8.15 ± 0.29b | 0.13 ± 0.01a | 1.16 ± 0.06a | 7.61 ± 0.82a | |
P(P) | 0.000 | 0.000 | 0.000 | 0.000 | |
P(D) | 0.000 | 0.000 | 0.000 | 0.000 | |
P(U) | 0.000 | 0.000 | 0.000 | 0.000 | |
P(P×D) | 0.001 | 0.000 | 0.005 | 0.173 | |
P(P×U) | 0.000 | 0.000 | 0.217 | 0.024 | |
P(D×U) | 0.000 | 0.000 | 0.000 | 0.001 | |
P(P×D×U) | 0.000 | 0.069 | 0.000 | 0.070 |
JZ, the low altitude population; DT, the high altitude population. ANOVA: P(P) : population effect; P(D) : drought effect; P(U) : UV-B effect; P(P×D) : population × drought effect; P(P×U) : population × UV-B effect; P(D×U) : drought × UV-B effect; P(P×D×U) : population × drought × UV-B effect. W, well-watered; WU, well-watered+enhanced UV-B radiation condition; D, drought; DU, drought+enhanced UV-B radiation condition. Values followed by the same letter in the same column are not significantly different at the P < 0.05 level according to Duncan’s multiple range test. Values are means± SE, n = 5.