*2.5. Influence of LED-Light Irradiation on Seedling Growth*

In most of the LED treatments in wheat seedlings, there were no statistically significant differences in leaf length, compared to control (FL) seedlings (Figure 4). However, the root growth of wheat sprouts treated with LED light irradiation for 3 days was significantly reduced, compared to that of the controls. Interestingly, further LED treatment on 5 and 7 days did not produce a significant impact on root growth, except under blue LED irradiation on day 7. Nonetheless, continuing white and red LED irradiation up to 9 days reduced root growth, which was statistically significant. In terms of light quality, the highest reduction in root growth was observed under white LED irradiation. Like wheat sprouts, the root growth in barley sprouts was altered by specific light qualities, in accordance with the growth period. Red LED irradiation consistently reduced barley root growth across all growth periods. White or blue LED irradiation also resulted in root growth reduction in one or more growth periods. Although initial treatment with red LED irradiation (on day 3) reduced leaf growth in barley sprouts, the extending the irradiation for 7 or 9 days had a positive impact on barley leaf growth. LED treatment in wheat sprouts showed that the leaf growth was mostly not altered.

their highest expression under red LED light irradiation (Figure 3D,F–H). Likewise, the highest

**Figure 3.** Relative quantification of expression changes in flavonoid and policosanol biosynthesisrelated genes in barley sprouts. (**A**–**C**) represent the relative expression levels of *UDP-Glc: Isovitexin 7*-*O-glucosyltransferase 1* (*OGT1*), *flavone synthase II* (*FNSII*), and *chalcone synthase 1* (*CHS1*), respectively. Likewise, (**D**–**H**) represent the expression patterns of different classes of *fatty acylcoenzyme A reductase (FAR)* genes. The results represent the qRT-PCR-based relative quantification of genes in barley sprouts exposed to fluorescent and LED (white, blue, and red) light irradiations. The gene expression was normalized using the internal control *HvActin*. \* (*p* < 0.05), \*\* (*p* < 0.001), and \*\*\* (*p* < 0.0001) indicate the statistical significance. *2.5. Influence of LED-light Irradiation on Seedling Growth*  **Figure 3.** Relative quantification of expression changes in flavonoid and policosanol biosynthesis-related genes in barley sprouts. (**A**–**C**) represent the relative expression levels of *UDP-Glc: Isovitexin 7*-*O-glucosyltransferase 1* (*OGT1*), *flavone synthase II* (*FNSII*), and *chalcone synthase 1* (*CHS1*), respectively. Likewise, (**D**–**H**) represent the expression patterns of different classes of *fatty acyl-coenzyme A reductase (FAR)* genes. The results represent the qRT-PCR-based relative quantification of genes in barley sprouts exposed to fluorescent and LED (white, blue, and red) light irradiations. The gene expression was normalized using the internal control *HvActin*. \* (*p* < 0.05), \*\* (*p* < 0.001), and \*\*\* (*p* < 0.0001) indicate the statistical significance. *Plants* **2020**, *9*, x FOR PEER REVIEW 8 of 15

**Figure 4.** Leaf and root growth parameters of fluorescent and light-emitting diode (LED) light (white, blue, and red) irradiated barley and wheat seedlings at different growth periods. (**A**) and (**C**) represent barley growth parameters, while (**B**) and (**D**) represent the growth parameters of wheat sprouts. \* (*p* < 0.05), \*\* (*p* < 0.001), and \*\*\* (*p* < 0.0001) indicate the statistical significance. **Figure 4.** Leaf and root growth parameters of fluorescent and light-emitting diode (LED) light (white, blue, and red) irradiated barley and wheat seedlings at different growth periods. (**A**,**C**) represent barley growth parameters, while (**B**,**D**) represent the growth parameters of wheat sprouts. \* (*p* < 0.05), \*\* (*p* < 0.001), and \*\*\* (*p* < 0.0001) indicate the statistical significance.

barley and wheat sprouts using varying light qualities.

enhance the nutritional functionality of the target crops through selective application of light resources and photoperiodism. The application of LEDs for special metabolite production is considered promising, where it has been shown that the metabolic profiles also depend on several other factors, including crop genetics [18,26,31]. The increasing application of LED irradiation sources for the development of designer foods/functional foods may revolutionize the food industry. In this study, we attempted to enhance the *C*-glycosylated flavones/flavonoids and policosanol contents in

Phytochromes and cryptochromes are the specialized photoreceptors of plants that sense the

*C*-glycosylated flavones constitute the major portion of flavonoids found in barley seedlings [32]. Saponarin (isovitexin-7-O-glucoside) is a major *C*-glycosylated flavone, which is naturally present in young barley seedlings [11]. Among cellular organelles, saponarin is efficiently stored in vacuoles [33] and high accumulation is typically observed in primary leaves [4]. Similarly, isoorientin and isoschaftoside are the major *C*-glycosylated flavones often reported in wheat seedlings [29]. These *C*glycosylflavones have potential roles as beneficial flavonoids in the human diet [4,8,34]. In this study, we found that the *C*-glycosylflavone (saponarin, isoorientin, and isoschaftoside) content was high in the early growth stages of seedlings, where the maximum accumulation was induced by blue LED

**3. .Discussion** 
