Carbon dioxide enrichment promoted the growth, yield, and light‐use efficiency of lettuce in a plant factory with artificial lighting

Abstract

Lettuce (Latuca sativa L.) is a commercially important crop and a good candidate for production in a plant factory with artificial lighting (PFAL). To explore the influence of CO 2 enrichment (eCO 2 ) on lettuce growth, light-use efficiency (LUE) and various aspects of the growth indicators were specifically assessed. Three CO 2 concentrations ([CO 2 ]): ambient CO 2 (as the control, approximately 400 μmol mol −1 ), approximately double the ambient (DA-CO 2 , 800 ± 50 μmol mol −1 ), and approximately quadruple the ambient (QA-CO 2 , 1600 ± 50 μmol mol −1 ) were applied for 30 d. The results indicated that plant height, stem diameter, number of leaves, root length, leaf width, and maximum leaf area were all positively related to [CO 2 ], which illustrated that growth was greater in the treatments with eCO 2 than under ambient CO 2 . The daily average assimilation rate (DAAR), the average dry weight growth rate (GRdw), and yield were also greater for plants grown under DA-CO 2 and QA-CO 2 than under ambient CO 2 (DAAR increased by 25.45% and 42.27%, GRdw increased by 28.76 and 37.55%, and yield increased by 33.65 and 44.16%, respectively). Lightuse efficiency increased by 28.51 and 41.12% for DA-CO 2 and QA-CO 2 compared with ambient CO 2 , respectively. We concluded that eCO 2 has the potential to enhance production as well as light utilization in PFAL. INTRODUCTIONA plant factory with artificial lighting (PFAL) is a closed plant production system where electrical lighting is used for crop production and where the environmental parameters [temperature, humidity, and CO 2 concentration ([CO 2 ])] controlled automatically and precisely, so that plant growth in the fac-Abbreviations: [CO 2 ], CO 2 concentration; Chl, chlorophyll; DA-CO 2 , approximately double the ambient CO 2 (800 ± 50 μmol•mol -1 ); DAAR, daily average assimilation rate; eCO 2 , CO 2 enrichment; GRdw, average dry weight growth rate; LUE, light-use efficiency; PFAL, plant factory with artificial lighting; QA-CO 2 , approximately quadruple the ambient CO 2 (1,600 ± 50 μmol•mol -1 ).This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Higher Light Intensity Combined with Early Topping Improve the Yield and Quality of Pea Shoots in LED Plant Factory

“…Alternatively, it may correspond to the transition of pea plants into the reproductive growth stage (Figure 1). These observations are consistent with the findings of Chen et al [32], where the photosynthetic capacity of lettuce leaves displayed an initial increasing trend during the first 25 days after transplanting, followed by a rapid decline after 5 days. This indicated that the plant was growing poorly during this period and could not improve its growth further at the same level of energy consumption.…”

“…In this study, it was found that light intensity was positively correlated with soluble sugar and vitamin C content in leaves, as well as vitamin C content in stems, among which could significantly increase vitamin C content in leaves (Figure 6). This was similar with the results of Chen et al [32] that light intensity could improve the nutritional value, and the higher light intensity leads to higher levels of vitamin C. However, there was no significant difference in nitrate content in leaves of pea shoots under three levels of light intensity (Figure 4D); nevertheless, light intensity showed a positive correlation with nitrate content in stems of pea shoots. Thus, the conclusion of Voutsinos et al [33] that higher light intensity provides more carbohydrate and photochemical energy to stimulate nitrate assimilation into amino acid in vegetable leaves was not confirmed, but the same as the research results of Maria et al [34], light intensity has no significant effect on nitrate accumulation.…”

“…Crops yield and quality as well as input resource use efficiency are important factors to evaluate PFALs performance [37], among which the cost of electricity consumed by artificial lighting is one of the main challenges limiting commercial PFALs for leaf vegetable production. LUE was defined as the ratio of accumulated dry weight of a plant during a certain planting period to the amount of PAR absorbed by the canopy of the plant during that period [38], which is affected by factors such as light intensity [39], temperature [40] and CO2 [32,38]. Results of previous studies on the effect of light intensity on LUE are contradictory.…”

Higher Light Intensity Combined with Early Topping Improves the Yield and Quality of Pea Shoots in LED Plant Factory

“…In this study, it was found that light intensity was positively correlated with soluble sugar and vitamin C content in leaves, as well as vitamin C content in stems, which could significantly increase vitamin C content in leaves (Figure 6). This was similar to the results of Chen et al [31], which showed that light intensity could improve nutritional value and that higher light intensity led to higher levels of vitamin C. However, there was no significant difference in nitrate content in the leaves of pea shoots under three levels of light intensity (Figure 4D). Nevertheless, light intensity showed a positive correlation with nitrate content in the stems of pea shoots.…”

Life Cycle Assessment of Carbon Capture by an Intelligent Vertical Plant Factory within an Industrial Park

“…Chowdhury et al [33] established five environmental conditions in a plant factory for comparison and discovered the best CO 2 concentration, humidity, and temperature ranges for kale growth and total glucosinolate content, respectively. Chen et al [34] have found that elevated CO 2 concentrations in a PFAL positively influenced lettuce growth, light-use efficiency, and yield, demonstrating the potential of CO 2 enrichment in PFAL systems. Zhiwei T et al [35] investigated the effects of LED lighting arrangement, light source type, and switching intervals on plant growth in artificial light plant factories, aiming to achieve an optimal cultivation strategy.…”