AI+200 and AI+160 were short-term (one
growing season) abrupt increase of [CO2] by
~200 μmol mol-1 and
~160 μmol mol-1, respectively. CI:
constant increase of [CO2] by ~200
μmol mol-1 based on ambient [CO2]
for four generations. SI: stepwise increase of [CO2]
for four generations with the [CO2] being
~40, 80, 120 and 160 μmol mol-1 higher
than ambient in each generation. Significance levels are indicated by *,
** and *** for p <0.05, p <0.01 andp <0.001.
Table 5 Predawn values of Fv/Fm (maximum
photochemical efficiency of PS II), ψo (probability that
trapped exciton moves an electron further than QA-),
φEo (electron transport quantum yield) and
PIABS (performance index) and results of analysis of
variance among growth stages under different treatment of
CO2 concentration [CO2] elevation.