Growth under elevated CO₂ conditions increases plant weight, tissue carbon content, and appearance in leafy green vegetables

With an increasingly health-conscious society and growing population, production of leafy green vegetables has turned to unconventional practices to provide increased yields of high-quality products.
One method is to bring production indoors away from quality diminishing hazards associated with field conditions including climactic and biological stressors as well as human disease causative agents.
However, the cost of the infrastructure needed for controlled environment production must be economically justifiable.
A controlled environment study evaluated seven commercial green leaf vegetable cultivars for their reaction to elevated CO₂. Enclosures (0.68 m³) were constructed and injected with CO₂ to simulate real-world greenhouse conditions.
Each enclosure within each replicate received one of four target CO₂ concentrations (ambient, 900, 1400, and 1900 ppm). Within each enclosure experimental plants of seven cultivars were evaluated at four harvest dates (16, 20, 24, 28 days after planting (DAP)). At each harvest date, plants were destructively evaluated for yield, appearance, and CO₂ usage.
The CO₂ use increased linearly with increased CO₂ concentration.
Plants receiving elevated CO₂ had increased carbon content in dried tissues relative to ambient conditions and did not differ from one another.
Plant biomasses were significantly increased over ambient conditions 24 days after planting under the highest tested concentrations and at all concentrations 28 DAP. In most cultivars (excluding ‘Revere’ spinach) biomasses increased due to elevated CO₂ relative to ambient conditions.
Plant appearance was positively influenced by high (≥1400 ppm) concentrations leading to greener leaves as indicated by SPAD readings, without adverse effects to leaf shape as indicated by length:width ratio.
Overall, under simulated greenhouse conditions, elevated CO₂ positively impacted green leaf vegetable production using commercial cultivars, even though specific alterations were cultivar specific.
Increased tissue carbon content suggests potential for greater carbon capture under elevated CO₂ greenhouse conditions.

XIII International Controlled and Modified Atmosphere Research Conference – CAMA2021

J.E. Stenger, M. Brooke, A. Svyantek, N. Theisen, H. Hatterman-Valenti

carbon dioxide, Lactuca sativa, Spinacia oleracea, Brassica oleracea, Eruca vesicari, greenhouse, controlled environment

https://doi.org/10.17660/ActaHortic.2024.1386.50