Elevated Ultraviolet-B Radiation Reduces Concentrations of Isoflavones and Phenolic Compounds in Soybean Seeds

Abstract

The gradual disruption of the ozone layer in the stratosphere has resulted in increased exposure of plants to ultraviolet‐B (UV‐B, 280–315 nm) radiation. UV‐B radiation is known to affect crop growth and quality negatively. A study was conducted to determine the impact of elevated UV‐B radiation levels on the isoflavones and phenolic compound concentrations of seven soybean varieties. UV‐B radiation significantly reduced the concentration of most isoflavones and phenolic compounds in soybean seeds. Exposure to elevated UV‐B levels overall resulted in 35 % reduction in total isoflavones and 31 % in phenolic compounds concentrations. The effect on individual isoflavones and phenolic compounds depended on the compound and variety, but UV‐B overwhelmingly reduced concentrations. This study suggests that increased UV‐B radiation negatively impacted soybean quality by reducing the concentration of compounds that have health‐beneficial properties.

Effects of PAR and UV‐B Radiation on Herbal Yield, Bioactive Compounds and Their Antioxidant Capacity of Some Medicinal Plants Under Controlled Environmental Conditions

“…Exposure to elevated UV‐B levels overall resulted in 35% reduction in total isoflavones and 31% in phenolic compounds concentrations. The effect on individual isoflavones and phenolic compounds depended on the compound and variety, but UV‐B overwhelmingly reduced the concentrations . St. John's wort, grown under different levels of UV‐B radiation, was analyzed for its concentrations of flavonoids, tannins and hypericin.…”

Ultraviolet-B Radiation Alters Soybean Growth and Seed Quality

“…Seed number per pod was less affected by changes in UV-B light treatment, compared with the pod numbers per plant. However, enhanced UV-B radiation has been reported to have no significant effect on effective pod-filling period, but the seed size was negatively impacted and decreased 12% for three sensitive cultivars [11]. Reduction of seed size was mainly due to the decrease of cotyledon cell number [12].…”

“…Seed growth rate was shown to be a function of the cotyledon cell number and the supply of assimilate to the developing cotyledons [34]. Reduction of seed size was mainly due to the decrease of cotyledon cell number [11].…”

“…A negative correlation has been reported between protein and oil concentration and yield in many soybean cultivars [17], and a negative correlation between protein and oil [18]. The average soybean seed contains 9% to 12% total soluble carbohydrates, of which 4% to 5% are sucrose (C 12 H 22 O 11 ), 1% to 2% are raffinose (C 18 H 32 O 16 ), and 3.5% to 4.5% stachyose (C 24 H 42 O 21 ) [11]. Raffinose and stachyose are undesirable components because they have detrimental effects on the nutritive value of the meal and are indigestible by human and animals, often causing flatulence and diarrhea in non-ruminants [18].…”

Exploiting Phenylpropanoid Derivatives to Enhance the Nutraceutical Values of Cereals and Legumes

“…Likewise, soil drought reduced the total phenolic content in the seeds of pea ( Pisum sativum L.) and yellow lupin ( Lupinus luteus L.; Juzoń et al, 2013 ). In mung bean [ Vigna radiata (L.) R. Wilczek], water deficit reduced the total phenolics content (Afzal et al, 2014 ), while elevated UV-B radiation significantly reduced the concentrations of isoflavones and phenolic compounds in soybean seed (Kim et al, 2011 ). Genotypic differences in response to elevated ozone were noted across mung-bean cultivars, i.e., some cultivars were more sensitive to ozone (O 3 ) stress (as measured by differences in antioxidants, metabolites, growth, total biomass, and yield) than others, suggesting the possibility of selection of suitable O 3 resistant cultivars with improved phenylpropanoids in seeds for areas experiencing high concentation of O 3 (Chaudhary and Agrawal, 2015 ).…”