Effects of ultraviolet-B radiation on crop growth, development, yield and leaf pigment concentration of tartary buckwheat ( Fagopyrum tataricum) under field conditions

Abstract

Tartary buckwheat ( Fagopyrum tataricum Gaertn.) crops were grown in sheltered field plots for two consecutive seasons under reduced, near-ambient and two supplemental levels of ultraviolet-B radiation (UV-B, 280–315 nm). The effects of different UV-B treatments on crop growth, development, yield and leaf pigment levels were determined. All four treatments were replicated three times in a randomized complete block design. Near-ambient solar UV-B (approximately 84–88% of solar UV-B) was provided by using a Teflon film, attenuated solar UV-B radiation (43–49% reduction in solar UV-B) by using a cellulose acetate film, and supplemental UV-B radiation by the use of UV fluorescent lamps (two levels: 5.30 and 8.50 kJ m −2 day −1). The prevailing ambient solar radiation caused a negative effect on plant growth and yield. The crop growth, total biomass, final seed yield, thousand-grain weight and the amount of photosynthetic pigments decreased under near-ambient and enhanced UV-B radiation, while crop development was promoted by enhanced UV-B radiation. Leaf rutin concentration and the amount of UV-B absorbing compounds were increased by UV-B with the exception of the 8.50 kJ m −2 day −1 supplemental levels. Our results showed that tartary buckwheat is a potentially UV-B sensitive species, and the crop response to UV-B radiation is associated with UV-B intensity, environmental factors and growing season.