UV-B radiation increases anthocyanin levels in cotyledons and inhibits the growth of common buckwheat seedlings

Abstract

The impact of short-term UV-B treatment on the content of individual flavonoids and photosynthetic pigments in cotyledons and the growth of common buckwheat (Fagopyrum esculentum Moench) seedlings was investigated. Seeds of four common buckwheat cultivars were germinated in darkness over a period of 4 days and acclimatized for 2 days under a 16/8 h light/dark photoperiod at 24/18 °C day/night, and exposure to 100-120 μmol • m -2 • s -1 of photosynthetically active radiation (PAR). Seedlings were divided into three batches, including two batches subjected to different doses of UV-B (5 W • m -2 and 10 W • m -2 , one hour per day) for 5 days, and a control group exposed to PAR only. Exposure to UV-B increased anthocyanin levels in the cotyledons of all examined cultivars, it inhibited hypocotyl elongation, but did not affect the content of photosynthetic pigments. Flavone concentrations increased in cv. Red Corolla and Kora, remained constant in cv. Panda and decreased in cv. Hruszowska. Exposure to UV-B decreased rutin levels in cv. Hruszowska, but not in the remaining cultivars. Cultivars Hruszowska, Panda and Kora appeared to be less resistant to UV-B than Red Corolla. Higher resistance to UV-B radiation in Red Corolla can probably be attributed to its higher content of anthocyanins and rutin in comparison with the remaining cultivars.

The Effects of Ultraviolet A/B Treatments on Anthocyanin Accumulation and Gene Expression in Dark-Purple Tea Cultivar ‘Ziyan’ (Camellia sinensis)

“…Anthocyanin contents in all of the UV treatments were significantly higher than those in white light treatment. In previous studies, UV-B has been shown to increase anthocyanin levels [51,57,58], and UV-A has also been showed to promote anthocyanin accumulation [41,59]. In our study, the result indicated that the effect of anthocyanin accumulation induced by different UV light was different.…”

“…The anthocyanin biosynthesis pathway in higher plants is well understood, and anthocyanin synthesis is easily affected by environmental factors such as light (including light quality, light intensity, and photoperiod), temperature, and water. Light quality, especially UV radiation and some other specific light qualities (e.g., red and blue light), could regulate anthocyanin biosynthesis in fruits and induce accumulation of anthocyanin, which have been reported in previous studies [51][52][53][54]. However, most of the previous studies focused on the effect of UV on anthocyanin content and one or several genes or enzyme activities in anthocyanin synthesis pathway.…”

Recent advances on the roles of flavonoids as plant protective molecules after UV and high light exposure

“…Enhanced levels of anthocyanins by UV‐B exposure were also reported in leaves of the tea plant “Ziyan” and cotyledons of four different common buckwheat cultivars, suggesting that a higher UV‐B resistance can be attributed to a higher anthocyanin content (Dȩbski et al 2016; Li et al 2020b). Moreover, tomato plants with decreased expression levels of the UV‐B photoreceptor UVR8 exhibited lower levels of anthocyanins after UV‐B exposure, demonstrating that UVR8 participates in plant acclimation to UV‐B by regulating the expression of the UVB‐responsive genes, such as HY5 and CHS , and that anthocyanin biosynthesis is regulated by UV‐B through the action of the UV‐B photoreceptor (Li et al 2018).…”

UV absorbing compounds in buckwheat protect plants and provide health benefit for humans / UV absorbirajoče snovi v ajdi ščitijo rastline in prispevajo k zdravju ljudi

“…Yao et al (2008) studied the effects of enhanced UV-B radiation on crop growth, morphology, reproduction, and physiology in three cultivars of Fagopyrum esculentum originating from different altitudes and revealed that enhanced UV-B radiation significantly affected plant growth, development and production, a cultivar originating from Qinghai-Tibet plateau being the most tolerant. Debski et al (2016) studied the impact of shortterm UV-B treatment on the content of flavonoids and photosynthetic pigments in cotyledons, and the growth of common buckwheat seedlings. Seedlings were subjected to different doses of UV-B, 5 W•m -2 and 10 W•m -2 .…”