Rising atmospheric CO2 may affect oil quality and seed yield of sunflower (Helianthus annus L.)

Abstract

The impact of rising atmospheric CO2 on crop productivity and quality is very important for global food and nutritional security under the changing climatic scenario. A study was conducted to investigate the effect of elevated CO2 on seed oil quality and yield in a sunflower hybrid DRSH 1 and variety DRSF 113, raised inside open top chambers and exposed to elevated CO2 (550 ± 50 µl l−1). Elevated CO2 exposure significantly influenced the rate of photosynthesis, seed yield and the quality traits in both hybrid and variety. Plants grown under elevated CO2 concentration showed 61–68 % gain in biomass and 35–46 % increase in seed yield of both the genotypes, but mineral nutrient and protein concentration decreased in the seeds. The reduction in seed protein was up to 13 %, while macro and micronutrients decreased drastically (up to 43 % Na in hybrid seeds) under elevated CO2 treatment. However, oil content increased significantly in DRSF 113 (15 %). Carbohydrate seed reserves increased with similar magnitudes in both the genotypes under elevated CO2 treatment (13 %). Fatty acid composition in seed oil contained higher proportion of unsaturated fatty acids (oleic and linoleic acid) under elevated CO2 treatment, which is a desirable change in oil quality for human consumption. These findings conclude that rising atmospheric CO2 in changing future climate can enhance biomass production and seed yield in sunflower and alter their seed oil quality in terms of increased concentration of unsaturated fatty acids compared with saturated fatty acids and lower seed proteins and mineral nutrients.