The rates of photosynthesis (PN) and transpiration (E) and the stomatal conductance (gs) were determined between 10:00 and 12:00 h, at an irradiance of 400-600 µmol(photon) m -2 s -1 , temperature of 30 ± 0.5°C, and 60-70% relative humidity, in three mature leaves per treatment, DAT interval and replicate, with a portable photosynthesis system (LCi, ADC BioScientific, UK).
Photosynthetic pigments: Foliar discs with area of 1 cm 2 were taken in triplicates from plants of each treatment and DAT interval, placed in assay tubes with 5 mL of N,N-dimethyl-formamide and kept in darkness for 24 h, after which the absorbance values were read at 480, 647, and 664 nm using spectrophotometer (UV-Vis Multiscan Go, Thermo Scientific, Finland). The concentrations of chlorophyll (Chl) a and b, total chlorophyll, and carotenoids were calculated according to Wellburn (1994) .
Growth and foliar area: On completion of each treatment, the height (cm) of each plant was measured and the samples were separated into leaves, stems, and roots. The total foliar area was determined per replicate, treatment, and DAT interval with a foliar area meter (LI-3100C, LI-COR BioSciences, Lincoln, NE, USA). The samples were dried at 60°C in a forced air oven (SHEL LAB, USA) to determine the dry mass of the foliar, stem, and root biomass.
Photosynthetic pigments: Foliar discs with area of 1 cm 2 were taken in triplicates from plants of each treatment and DAT interval, placed in assay tubes with 5 mL of N,N-dimethyl-formamide and kept in darkness for 24 h, after which the absorbance values were read at 480, 647, and 664 nm using spectrophotometer (UV-Vis Multiscan Go, Thermo Scientific, Finland). The concentrations of chlorophyll (Chl) a and b, total chlorophyll, and carotenoids were calculated according to Wellburn (1994) .
Growth and foliar area: On completion of each treatment, the height (cm) of each plant was measured and the samples were separated into leaves, stems, and roots. The total foliar area was determined per replicate, treatment, and DAT interval with a foliar area meter (LI-3100C, LI-COR BioSciences, Lincoln, NE, USA). The samples were dried at 60°C in a forced air oven (SHEL LAB, USA) to determine the dry mass of the foliar, stem, and root biomass.