Abstract
Using traditional photosynthesis-intercellular CO2
concentration (A-Ci) response (TACiR) curves to
obtain the maximum rates of ribulose-1,5-bisphosphate carboxylase
oxygenase carboxylation (Vcmax) and electron
transport (Jmax) is time-consuming and
labor-intensive. Instead, the rapid A-Ci response
(RACiR) technique provides a potential way with high efficiency.
However, multiple parameter settings of RACiR technique for different
plant life forms remain unclear. Here, we used Li-Cor 6800 to test the
applicability and optimum parameter settings of RACiR curves for
evergreens and herbs. We set 11 groups of [CO2],
i.e., R1 (400-1500 ppm), R2 (400-200-800 ppm), R3 (420-20-620 ppm), R4
(420-20-820 ppm), R5 (420-20-1020 ppm), R6 (420-20-1220 ppm), R7
(420-20-1520 ppm), R8 (420-20-1820 ppm), R9 (450-50-650 ppm), R10
(650-50 ppm) and R11 (650-50-650 ppm), and made contrasts between TACiR
and RACiR curves. We found that Vcmax and
Jmax calculated by TACiR and RACiR overall showed
no significant differences across 11 [CO2] gradients
(P<0.05). The efficiency and accuracy of R2, R3, R4, R9
and R10 showed higher superiority than others. Moreover, the accuracy of
manual empty chamber correction method was higher than the automatic
method. In conclusion, the RACiR technique could be generally used to
obtain photosynthetic parameters with higher efficiency than traditional
methods for various life forms.