Division of Animal, Horticultural and Food Science, Chungbuk National University, Cheongju 28644, Korea.
Brain Korea 21 Center for Bio-Resource Development, Chungbuk National University, Cheongju 28644, Korea.
Int J Mol Sci. 2019 Oct 8;20(19):4950. doi: 10.3390/ijms20194950.
Short-term abiotic stress treatment before harvest can enhance the quality of horticultural crops cultivated in controlled environments. Here, we investigated the effects of combined chilling and UV-A treatment on the accumulation of phenolic compounds in kale ( var. ). Five-week-old plants were subjected to combined treatments (10 °C plus UV-A LED radiation at 30.3 W/m) for 3-days, as well as single treatments (4 °C, 10 °C, or UV-A LED radiation). The growth parameters and photosynthetic rates of plants under the combined treatment were similar to those of the control, whereas UV-A treatment alone significantly increased these parameters. Maximum quantum yield () decreased and HO increased in response to UV-A and combined treatments, implying that these treatments induced stress in kale. The total phenolic contents after 2- and 3-days of combined treatment and 1-day of recovery were 40%, 60%, and 50% higher than those of the control, respectively, and the phenylalanine ammonia-lyase activity also increased. Principal component analysis suggested that stress type and period determine the changes in secondary metabolites. Three days of combined stress treatment followed by 2-days of recovery increased the contents of quercetin derivatives. Therefore, combined chilling and UV-A treatment could improve the phenolic contents of leafy vegetables such as kale, without growth inhibition.
短期非生物胁迫处理在收获前可以提高在受控环境中种植的园艺作物的品质。在这里，我们研究了冷藏和 UV-A 联合处理对羽衣甘蓝（ var. ）中酚类化合物积累的影响。五周龄的植物接受了为期 3 天的联合处理（10°C 加 30.3 W/m 的 UV-A LED 辐射），以及单一处理（4°C、10°C 或 UV-A LED 辐射）。与对照相比，联合处理下植物的生长参数和光合速率相似，而单独的 UV-A 处理显著增加了这些参数。UV-A 和联合处理会导致最大量子产量（）下降和 HO 增加，表明这些处理诱导了羽衣甘蓝的应激。与对照相比，联合处理 2 天和 3 天以及恢复 1 天后的总酚含量分别提高了 40%、60%和 50%，苯丙氨酸解氨酶活性也增加了。主成分分析表明，胁迫类型和时间决定了次生代谢物的变化。3 天的联合胁迫处理后再恢复 2 天可以增加槲皮素衍生物的含量。因此，冷藏和 UV-A 的联合处理可以在不抑制生长的情况下提高羽衣甘蓝等叶菜类蔬菜的酚类含量。
