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Ascorbic acid (AsA) is a crucial antioxidant in vegetables. Celery (Apium graveolens L.) is a vegetable of Apiaceae and is rich in AsA. Till now, the effects of different storage conditions on celery morphological characteristics, anatomical features, and antioxidant accumulation are unclear. Here, the celery cvs. 'Sijixiaoxiangqin' and 'Liuhehuangxinqin' were selected as experimental materials, and the two celery plants grown for 65 days were harvested from soils and stored in light at room temperature (25 °C), darkness at low temperature (4 °C), and darkness at room temperature (25 °C) for 0, 6, 24, 30, 48, and 54 h, respectively. The results showed that celery in darkness had better water retention capacity than celery in light. Morphological changes in celery mesophyll, leaf veins, and petioles were the least in darkness at low temperature (4 °C). The weight loss rate and wilting degree in darkness at low temperature (4 °C) were the lowest, and the AsA content remained at a high level. The expression patterns of GDP-d-mannose pyrophosphorylase (AgGMP) and l-galactose dehydrogenase (AgGalDH) were similar to the change of AsA content. The results indicated that low temperature and dark was the optimized storage condition for 'Sijixiaoxiangqin' and 'Liuhehuangxinqin' celery. AgGMP and AgGalDH genes may play an important role in the accumulation of AsA in celery. This paper will provide potential references for prolonging the shelf life of celery and other horticultural crops. [ABSTRACT FROM AUTHOR]

Carotenoids are liposoluble pigments found in plant chromoplasts that are responsible for the yellow, orange, and red colors of carrot taproots. Drought is one of the main stress factors affecting carrot growth. Carotenoids play important roles in drought resistance in higher plants. In the present work, the carotenoid contents in three different-colored carrot cultivars, 'Kurodagosun' (orange), 'Benhongjinshi' (red), and 'Qitouhuang' (yellow), were determined by ultra-high-performance liquid chromatography (UPLC) after 15% polyethylene glycol (PEG) 6000 treatment. Real-time fluorescence quantitative PCR (RT-qPCR) was then used to determine the expression levels of carotenoid synthesis- and degradation-related genes. Increases in β-carotene content in 'Qitouhuang' taproots under drought stress were found to be related to the expression levels of DcPSY2 and DcLCYB. Increases in lutein and decreases in α-carotene content in 'Qitouhuang' and 'Kurodagosun' under PEG treatment may be related to the expression levels of DcCYP97A3, DcCHXE, and DcCHXB1. The expression levels of DcNCED1 and DcNCED2 in the three cultivars significantly increased, thus suggesting that NCED genes could respond to drought stress. Analysis of the growth status and carotenoid contents of carrots under PEG treatment indicated that the orange cultivar 'Kurodagosun' has better adaptability to drought stress than the other cultivars and that β-carotene and lutein may be involved in the stress resistance process of carrot. [ABSTRACT FROM AUTHOR]

Gibberellins (GAs) are important growth regulators involved in plant development processes. However, limited information is known about the relationship between GA and xylogenesis in carrots. In this study, carrot roots were treated with GA. The effects of applied GA on root growth, xylem development, and lignin accumulation were then investigated. Results indicated that GA treatment dose-dependently inhibited carrot root growth. The cell wall significantly thickened in the xylem parenchyma. Autofluorescence analysis with ultraviolet (UV) excitation indicated that these cells became lignified because of long-term GA treatment. Moreover, lignin content increased in the roots, and the transcripts of lignin biosynthesis genes were altered in response to applied GA. Our data indicate that GA may play important roles in xylem growth and lignification in carrot roots. Further studies shall focus on regulating plant lignification, which may be achieved by modifying GA levels within plant tissues. [ABSTRACT FROM AUTHOR]