Light Supplement and Carbon Dioxide Enrichment Affect Yield and Quality of Off‐Season Pepper

Abstract

Core Ideas Carbon dioxide enrichment and light supplement significantly increased the photosynthetic rate, yield, and water use efficiency. Carbon dioxide enrichment reduced fruit nutrition quality, whereas light supplement improved it. Applying light supplement and a CO2 concentration of 550 μmol mol−1 can optimize yield and quality. Off‐season vegetable crops in a greenhouse need supplementary light intensity and CO2 concentration to obtain good growth and fruit quality. The objective of this study was to investigate the effects of supplementary light intensity and CO2 concentration on the photosynthesis, yield, and fruit quality of fresh hot pepper (cultivar Meite). Two light intensities—supplementary (SLI) and natural (NLI) light intensity with the averaged photosynthetic active radiation of the whole growth period of 463 and 233 μmol m−2 s−1, respectively—and 4 CO2 concentrations (400, 550, 700, and 900 μmol mol−1) were conducted on pepper planted in pots in phytotrons over the autumn and winter seasons in the arid Northwest region of China. Results showed that: (i) CO2 enrichment significantly increased the net photosynthetic rate (Pn), water use efficiency (WUE), yield parameters, and fruit storage qualities, but decreased the fruit nutrition qualities to different extents. (ii) SLI increased Pn, WUE, and fruit nutrition qualities to different extents, and increased fruit yield per plant (FYPP) by 157%. (iii) The treatment with SLI and a CO2 concentration of 550 μmol mol−1 can maximize the overall quality of pepper fruits and significantly increase FYPP with a first ranking in the technique for order of preference by similarity to the ideal solution (TOPSIS) method. Therefore, the yield of pepper grown in the off‐season was increased and fruit quality was maintained by SLI and moderately increasing CO2 concentration (550 μmol mol−1).

Increased CO2 and light intensity regulate growth and leaf gas exchange in tomato

“…It has now reached 400 µmol CO 2 mol −1 , with levels expected to double by the end of this century (Kumari and Agrawal , Urban et al ). Elevated CO 2 has a number of influences on plant growth and physiological processes, including root growth, dry mass accumulation, mineral uptake and photosynthesis (Ainsworth and Long , Pérez‐López et al , Tomimatsu et al , Pérez‐López et al , Chang et al , Li et al ). Elevated CO 2 can increase growth (dry matter accumulation) and so decrease the concentrations of minerals in plants due to a dilution effect (Kumari et al ).…”

“…Furthermore, it can reduce water consumption, thereby increasing dry matter production and yield via increased plant‐level water use efficiency (WUE plant ; Kaminski et al , Pazzagli et al , da Silva et al ). Moreover, elevated CO 2 also increases Pn while decreasing Tr, therefore increasing leaf‐level water use efficiency (WUE leaf ; Mamatha et al , Li et al ).…”

“…In tomato, increasing the light intensity within a certain range can increase growth, chlorophyll content, biomass accumulation, Pn, leaf nitrogen content (LNC) and plant health index (Fan et al , Proietti et al ). Furthermore, it can upregulate the activities of ribulose‐1,5‐bisphosphate carboxylase/oxygenase (Rubisco) and fructose‐1,6‐bisphosphatase (FBPase; Yu and Wang ) and thereby increasing growth, carbon assimilation and water use efficiency (WUE; Walters , Li et al ).…”

“…The combination of increased CO 2 and increased light intensity can promote dry matter accumulation and carbon assimilation (Proietti et al , Naing et al , Li et al , Lanoue et al ). These effects may be due to a synergistic effect on Pn to produce more carbohydrates – but this needs further investigation.…”

“…With global climate change, water shortages will probably increase in frequency and in severity (Garcia Galiano et al ). Just how we may increase WUE is attracting increased attention (Li et al , Zhang et al ). Many studies have reported that elevated CO 2 can increase WUE plant .…”