. 2014 Feb 5;19(2):1795–1819. doi: 10.3390/molecules19021795

Table 6.

Impact of potassium fertilization on the leaf gas exchange under water stress at different growth stages of rice. Data are means ± standard error of differences between means (SEM). N = 12. Means not sharing a common single letter were significantly different at p ≤ 0.05.

Treatments	Net photosynthesis (µmol/m²/s)	Stomatal conductance (mmol/m²/s)	Transpiration rate (mmol/m²/s)	Water use efficiency (µmol/m²/s CO₂ assimilated per mmol/m²/ water transpired
80CF	15.18 ± 0.24 ^b	0.33 ± 0.01 ^a	7.83 ± 0.34 ^b	1.95 ± 0.03 ^c
120PW15	15.69 ± 0.45 ^b	0.35 ± 0.01 ^a	7.60 ± 0.21 ^b	2.18 ± 0.02 ^a
120DS15V	15.72 ± 0.24 ^b	0.36 ± 0.02 ^a	7.82 ± 0.13 ^b	2.01 ± 0.01 ^b
120DS25V	16.31 ± 0.31 ^a	0.36 ± 0.01 ^a	8.09± 0.21 ^a	2.02 ± 0.02 ^b
120DS15R	14.28 ± 0.25 ^c	0.31 ± 0.02 ^a	7.19 ± 0.12 ^c	1.98 ± 0.04 ^b

Notes: 80CF = continuous flooding + 80 kg K₂O/ha; 120PW15 = periodical water stress for 15 days + 120 kg K₂O/ha; 120DS15V = drought stress for 15 days at the vegetative stage + 120 kg K₂O/ha; 120DS25V = drought stress for 25 days at the vegetative stage + 120 kgK₂O/ha; 120DS15R = drought stress for 15 days at the reproductive stage + 120 kg K₂O/ha]. A = net photosynthesis; g_s = stomatal conductance; E = transpiration rate; WUE = water use efficiency; f_o = initial fluorescence; f_v/f_o = maximum quantum yield of photochemical and non-photochemical process in photosystem II; f_v/f_m = maximum efficiency of photosystem II and TCC = total chlorophyll. Residual factor = Inline graphic = 0.350.