FTSW	Fraction of transpirable soil water
SWC	Soil water content
P N	Net photosynthesis
G s	Stomatal conductance
PSI	Photosystem I
PSII	Primary photochemistry/photosystem II (PSII)
Fv/Fm(φP0)	The maximum quantum yield of primary photochemistry (PSII), ((Fm-Fo)/Fm)
PAR	Photosynthetically active radiation
Chl	Chlorophyll
ChlF	Chlorophyll fluorescence
F o	Minimal fluorescence
FM	Maximal fluorescence
F V	Maximal variable fluorescence
ψ E0	The efficiency of trapped energy to move an electron further than QA−
TBARS	Thiobarbituric acid reactive substances
SOD	Superoxide dismutase
CAT	Catalase
APX	Ascorbate peroxidases
POX	Peroxidases
GR	Glutathione reductase
TS	Drought-tolerant sunflower variety (var. Bosfora)
SS	Drought-sensitive sunflower variety (var. 08 TR 003)
TM	Drought-tolerant maize variety (var. ADA-9516)
SM	Drought-sensitive maize variety (var. ADA-523).