This outdoor field experiment involved two treatments: (1) control plants
receiving ambient UV-B designated as (C) and (2) sUV-B-treated plants, subjected
to UV-B-supplemented dose (+1.8 kJ mÀ2) above ambient. For both treatments,
plots in three replicates were provided. Supplemental UV-B radiation was provided
by UV-B fluorescent lamps (UVB-313, Q Panel, Cleveland, USA) held in mobile
adjustable frame fitted 45 cm above and perpendicular to the plant canopy and the
distance between the top of the plant canopy and UV-B lamps was always kept
constant. Aluminum reflectance strip was used to avoid scattering of UV rays from
the upper side of the lamps.