Table 3.

Photosynthetic and PSII function performances under soil drought and rewatering (measured on 15–18 October 2005), with soil relative water contents (SRWCs) of control (75–80%), LD (60–75%), MD (50–60%), SD (35–50%), and ED (25–35%)

	gs	gi	Asat	α	Vc,max	Fv/Fm	ΦPSII	NPQ
Control	0.415±0.076 a	0.225±0.027 a	17.01±0.99 a	0.078±0.004 a	103.34±5.68 a	0.814±0.010 a	0.393±0.002 a	0.523±0.080 c
LD	0.412±0.048 a	0.217±0.029 a,b	18.00±1.36 a	0.080±0.003 a	100.12±1.82 a,b	0.816±0.003 a	0.369±0.024 a	1.064±0.081 b
MD	0.269±0.017 b	0.157±0.007 b,c	17.82±0.57 a	0.053±0.002 b	88.63±3.25 a,b	0.810±0.004 a	0.309±0.011 b	1.358±0.126 b
SD	0.218±0.012 b,c	0.120±0.017 c	13.21±0.58 b	0.030±0.001 c	90.62±1.37b c	0.791±0.002 b	0.246±0.037 b	2.090±0.070 a
ED	0.146±0.019 c	0.057±0.009 d	4.27±0.46 c	0.028±0.002 c	84.89±3.43 c	0.749±0.005 c	0.203±0.007 b	2.483±0.248 a
F	7.91	12.58	45.42	83.63	4.79	24.12	16.42	32.90
P	0.004	<0.01	<0.01	<0.01	0.020	<0.01	<0.01	<0.01
Performances after rewatering
R-MD	0.272±0.030 a*	0.180±0.013 a	18.18±0.95 a	0.077±0.001 a	107.71±20.68 a	0.820±0.003 a	0.312±0.012 a*	1.625±0.147 a*
R-SD	0.254±0.019 a*	0.148±0.012 a,b*	17.89±0.56 a	0.070±0.004 a,b	113.09±3.47 a	0.819±0.003 a	0.295±0.002 a*	1.824±0.042 a*
R-ED	0.249±0.009 a*	0.126±0.005 b*	18.95±1.49 a	0.067±0.003 b*	122.18±6.77 a*	0.767±0.054 a	0.268±0.021 a*	1.935±0.153 a*
F	0.94	5.88	0.26	2.64	0.32	0.96	2.52	1.58
P	0.441	0.069	0.778	0.150	0.736	0.44	0.160	0.28
PDL (%)
R-MD	34.41±8.02	19.82±5.87 a	–6.88±5.64	1.28±4.95 b	–4.23±20.01	–0.74±0.82	20.61±2.60	–210.71±22.92
R-SD	38.75±8.20	34.26±5.87 a,b	–5.17±7.46	10.26±1.04 a,b	–9.44±3.36	–0.61±0.98	24.94±0.22	–248.76±41.52
R-ED	39.95±9.5	43.82±2.37 b	–11.41±10.43	14.10±1.5 2a	–18.24±7.28	5.77±5.94	31.81±4.97	–269.98±34.91

R-MD, R-SD, and R-ED represent rewatering after the plants have undergone the corresponding pre-drought treatments.

A_sat is the light-saturated CO₂ accumulation rate (μmol mol⁻¹); F_v/F_m is the maximal efficiency of PSII photochemistry (dimensionless); g_s is stomatal conductance (mmol mol⁻¹); g_i is mesophyll conductance (mmol mol⁻¹); NPQ is non-photochemical quenching (dimensionless); PDL is pre-drought limitation; V_c,max is maximum carboxylation velocity (μmol mol⁻¹); α is the maximum photosynthetic quantum yield of CO₂ uptake (dimensionless); and Φ_PSII is the actual PSII efficiency (dimensionless). Asterisks indicate significance at the 0.05 level, compared with those of the control value.