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

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. (c) 2006 Elsevier B.V. All rights reserved.