Carbon Dioxide Enrichment Combined with Supplemental Light Improve Growth and Quality of Plug Seedlings of Astragalus membranaceus Bunge and Codonopsis lanceolata Benth. et Hook. f.

Abstract

Astragalus membranaceus Bunge and Codonopsis lanceolata Benth. et Hook. f. are two medicinal species used to remedy inflammation, tumor, and obesity in Eastern medicine. Carbon dioxide (CO2) and supplemental lighting are two methods to enhance the growth, yield, and quality of crops. However, few studies have focused on the synergistic effects of CO2 and the supplemental light source on plug seedlings of medicinal species. In this study, uniform seedlings were grown with no supplemental light (the control) or under one of three supplemental light sources [high pressure sodium (HPS), metal halide (MH), or mixed light-emitting diodes (LEDs)] combined with one of three levels of CO2 (350, 700, or 1050 μmol·mol−1). The supplemental light (100 μmol·m−2·s−1 photosynthetic photon flux density) and CO2 were provided simultaneously from 10:00 pm to 2:00 am every day. The results showed that the supplemental lighting (LEDs, MH, and HPS) greatly improved the seedling quality with greater dry weights (of the shoot, root, and leaf), stem diameter, leaf area, and Dickson’s quality index (DQI) than those of the control in both species. An enriched CO2 at 1050 μmol·mol−1 accelerated the growth and development of plug seedlings, evidenced by the increased root and leaf dry weights, stem diameter, and DQI compared to the those from the other two CO2 enrichment levels. Moreover, LEDs combined with 1050 μmol·mol−1 CO2 not only increased the contents of soluble sugars but also the starch content. However, an enriched CO2 at 700 μmol·mol−1 was more suitable for the accumulation of total phenols and flavonoids. Furthermore, LEDs combined with 700 or 1050 μmol·mol−1 CO2 increased the chlorophyll, quantum yield, and stomatal conductance at daytime and nighttime for A. membranaceus and C. lanceolata, respectively. In conclusion, the data suggest that LEDs combined with CO2 at 1050 μmol·mol−1 is recommended for enhancing the growth and development of plug seedlings of A. membranaceus and C. lanceolata.

Supplementary Light Source Affects Growth and Development of Carnation ‘Dreambyul’ Cuttings

“…The trends in soluble proteins and carbohydrates in the cuttings were similar to those of the root biomass and root activities ( Figure 6 and Table 2). Light-especially red and blue-can stimulate photosynthetic enzyme activities and improves stomatal opening, which is the foundation of photosynthesis [67]. Compared to HPS lamps, MH and LED-mix provide a higher percentage of red and blue lights, which resulted in a greater increase of soluble proteins and carbohydrates.…”

Role of Spectrum-Light on Productivity, and Plant Quality over Vertical Farming Systems: Bibliometric Analysis

“…It is a parameter that determines the amount of photoassimilates produced and affects who is growth, development, and productivity [37]. In general, it is assumed that LA and biomass accumulation in crops may be affected by some factors, such as light quality and radiation intensity, plant nutrition, substrate type, and container design and volume [38][39][40][41].…”

Light Emitting Diodes (LEDs) as Agricultural Lighting: Impact and Its Potential on Improving Physiology, Flowering, and Secondary Metabolites of Crops

“…Previous studies have concluded that plasma membrane H + -ATPase plays a critical role in regulating stomatal opening [114] and plays a crucial and primary role in regulating plant growth [115] and responses to environmental stimuli [116]. The opening and closing of stomatal guard cells are regulated by phototropins present in stomatal guard cells in response to blue light stimuli [117] to allow the uptake of CO2 to facilitate photosynthesis [112,118], which further leads to transpirational loss of water through leaves. In order to minimize the water loss, guard cells tend to close the stomatal pore during heavy sunlight or other high light conditions.…”