Abstract
Insufficient light in autumn–winter may prolong the production periods and reduce the quality of plug seedlings grown in greenhouses. Additionally, there is no optimal protocol for supplementary light strategies when providing the same amount of light for plug seedling production. This study was conducted to determine the influences of combinations of supplementary light intensity and light duration with the same daily light integral (DLI) on the morphological and physiological properties of cucumber seedlings (Cucumis sativus L. cv. Tianjiao No. 5) grown in a greenhouse. A supplementary light with the same DLI of 6.0 mol m−2 d−1 was applied with the light duration set to 6, 8, 10, or 12 h d−1 provided by light-emitting diodes (LEDs), and cucumber seedlings grown with sunlight only were set as the control. The results indicated that increasing DLI using supplementary light promoted the growth and development of cucumber seedlings over those grown without supplementary light; however, opposite trends were observed in the superoxide dismutase (SOD) and catalase (CAT) activities. Under equal DLI, increasing the supplementary light duration from 6 to 10 h d−1 increased the root surface area (66.8%), shoot dry weight (24.0%), seedling quality index (237.0%), root activity (60.0%), and stem firmness (27.2%) of the cucumber seedlings. The specific leaf area of the cucumber seedlings decreased quadratically with an increase in supplementary light duration, and an opposite trend was exhibited for the stem diameter of the cucumber seedlings. In summary, increased DLI or longer light duration combined with lower light intensity with equal DLI provided by supplementary light in insufficient sunlight seasons improved the quality of the cucumber seedlings through the modification of the root architecture and stem firmness, increasing the mechanical strength of the cucumber seedlings for transplanting.
Highlights
Vegetables are vital components of healthy diets, which are related to lower mortality and morbidity in adult life [1]
The aim of this study was to evaluate the impacts of white light-emitting diodes (LEDs) as supplementary light with equal daily light integral (DLI) on the leaf morphology, pigment content, photosynthetic characteristics, biomass accumulation, root architecture, and antioxidant enzyme activities of cucumber seedlings grown in a greenhouse
The chlorophyll content (SPAD) and photosynthetic characteristics of the cucumber seedlings were significantly influenced by supplementary light (Table 1)
Summary
Vegetables are vital components of healthy diets, which are related to lower mortality and morbidity in adult life [1]. In China, the vegetable planting area and the demand for vegetable seedlings were more than 20 million hectares and 680 billion in 2018, respectively [2]. Cucumber (Cucumis sativus L.) is one of the most cultivated vegetables worldwide and is economical to produce, with an annual production of 87.8 million tons in. Pronounced differences can be observed in terms of cucumber yield, with the highest and lowest cucumber yields in China being 150,000 kg per hectare and 56,000 kg per hectare, respectively [4]. Previous studies have demonstrated that the quality of vegetable seedlings affects the subsequent growth, yield, and the nutritional quality of mature plants at harvest [5,6]. High-quality seedlings are essential to increase crop yield and economic benefits
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
