Flavonoid and carotenoid content in floral organs of Iris pumila

Abstract

Flavonoids and carotenoids are plant pigments that play a variety of functional roles in higherplants. Beside their impacts on flower color, they are involved in plant growth, development andprotection against a wide range of environmental stressors. They act either as light attenuatorsand free radical scavengers (e.g. anthocyanins) or participate in non-photochemical quenching(carotenoids). To quantify the accumulation of flavonoids and carotenoids in different floral organs,ffty Iris pumila genotypes grown in a common-garden and belonging to different color classes(yellow, blue, violet, dark blue and dark violet) were assessed. One flower per each genotype washarvested and analyzed spectrophotometrically for the content of three flavonoids (anthocyanins,flavones, flavonols) and total carotenoids in different floral organs: falls, standards, stamens andstyle arms. While the quantity of flavonoids was found to be floral organ- and color morph-specific, the amount of carotenoids varied only among individual floral organs. The variation pattern ofthe analyzed compounds displayed identical trend - the lowest amounts were recorded in the stamen and style arm, and the highest in the standard and fall. The content of carotenoids appearedto be the highest in floral organs of the yellow color morphs, whereas in the blue, violet, dark blueand dark violet flower phenotypes its abundance was a half of that recorded for the yellow one.Conversely, the anthocyanin content was rather high in the floral organs of dark violet and darkblue color morphs, but extremely low in those of the yellow one. Our results clearly suggest that agreater accumulation of both plant pigments in sterile rather than in fertile flower organs could becausally related to their specifc function in the process of sexual reproduction, where the formerserve to attract plant pollinators, while the latter promote an efcient pollen deposition.