Effects of Water Stress on Carotenoid and Proline Contents in Kale (Brassica oleracea var. acephala) leaves

Abstract

BACKGROUND : Environmental stress has a major effect on the growth and yields of vegetables, and can significantly affect nutritionally important phytochemicals, causing large economic losses. METHODS AND RESULTS :The present study was aimed at exploring the effects of water stress on the carotenoid and proline contents in kale leaves to understand drought tolerance of kale plants. Kale was randomly divided into two groups at 57 days after sowing (DAS). One of the groups was well-watered (WW) and the other was water stressed (WS). Harvesting of kale leaves was started one day after treatment (58 DAS) and continued for 10 days (~67 DAS). We investigated the status of plant growth (leaf number, length, width, fresh weight) of kale throughout the study. Carotenoid (lutein, α-carotene, zeaxanthin, β-carotene) and proline contents were analyzed by high-performance liquid chromatography (HPLC). Our results showed that the total carotenoid contents ranged from 926.0 to 1,212.0 mg/kg dry wt. (at 3 and 2 days, respectively) in WW treatment and 887.8 to 1,157.4 mg/kg dry wt. (at 10 and 4 days, respectively) in WS treatment. The ratio of individual carotenoid to the total carotenoid contents of kale leaves was 51.4 for lutein, 4.44 for zeaxanthin, 2.76 for α-carotene, and 41.4% for β-carotene. Total carotenoid contents showed a significant reduction from 7 days (1,037.2 mg/kg dry wt.) to 10 days (887.8 mg/kg dry wt.) in WS treatment. The lutein content did not show a significant difference in WW between 7 and 10 days after treatment but showed a significant difference in WS treatment. The α-carotene content showed no significant difference between the treatments. However, zeaxanthin content was higher during 4 10 days and -β-carotene content was lower during 6 10 -days in WS than in WW on each harvest day. In WW, the proline content showed no significant difference, but in WS, the proline content started to increase at 7 days and almost doubled in 10 days. CONCLUSION : The marked increase in zeaxanthin and proline contents in kale leaves indicated that the two phytochemicals are associated with drought tolerance in the plant.

Abiotic stress-induced secondary metabolite production in Brassica: opportunities and challenges

“…Similarly, a significant reduction in total carotenoid content was reported for drought-stressed kale ( Brassica oleracea var. acephala ) leaves ( Lee et al., 2017 ). The ratio of individual carotenoids to the total carotenoid content of kale leaves was reported as 51.4% for lutein, 4.44% for zeaxanthin, 2.76% for α-carotene, and 41.4% for β-carotene.…”

Effects of Electro-conductivity on Growth of Beet and Turnip in the Reclaimed Land Soil

“…GSL 분석은 Inertsil ODS-3 column(150×3.0 mm I.D., particle size 3 μm), 가드 컬럼은 Inertsil ODS-2 Cartridge Guard column E(10×2.0 mm I.D., particle size 5 μm) (GL Science, Tokyo, Japan)을 사용하였고 HPLC ( (Sobhanian et al, 2011;Hong et al, 2015). 케일은 수 분 스트레스 기간이 증가할수록 수분 함량이 감소하였고 (Jeong et al, 2015), 케일의 생체중도 감소하는 경향을 보였 다 (Lee et al, 2017). 저온처리하여 생장한 케일은 온실에서 재배한 케일보다 생육이 더 낮은 경향을 보였다 (Hwang et al, 2017).…”