Growth, Plant Quality, and Survival of Sweet Cherry (Prunus avium L.) Seedlings are Enhanced by CO2 Enrichment

Abstract

<jats:p>Enrichment with CO<jats:sub>2</jats:sub> and a commercial mix of plant growth regulators were tested to improve the plant quality and survival of pregerminated cherry tree seedlings. Pregerminated seeds were transferred from a cold chamber to a climatic chamber where the CO<jats:sub>2</jats:sub> was set at 800 µmol·mol<jats:sup>−1</jats:sup> CO<jats:sub>2</jats:sub> or at the ambient CO<jats:sub>2</jats:sub> concentration. Also, half of the plants were sprayed with the mix of plant growth regulators and disposed randomly. The experiment lasted 18 days and physiological measurements, such as plant physiological status and growth, number of leaves, net CO<jats:sub>2</jats:sub> assimilation (A<jats:sub>CO2</jats:sub>), internal CO<jats:sub>2</jats:sub>, stomatal conductance, and transpiration, were taken every 4 days. Also, at the end of the experiment, other parameters—such as total leaf area, photosynthetic pigments, soluble sugars, and starch—were recorded or quantified. During the experiment, plants cultured under CO<jats:sub>2</jats:sub> enrichment exhibited a rapid increase in their photosynthetic rates, height, and leaf number; the commercial mix also increased plant height but inhibited leaf expansion and growth. At the end of the experiment, the amounts of starch and soluble sugars had increased in the plants grown under elevated CO<jats:sub>2</jats:sub>, compared with those plants grown in control conditions or with the commercial mix. Thus, culture at elevated CO<jats:sub>2</jats:sub> achieved higher percentages of plant survival and of plants in active growth. We suggest that CO<jats:sub>2</jats:sub> plays an important role—by increasing A<jats:sub>CO2</jats:sub>, water use efficiency, soluble sugars, and starch—which results in plants that are physiologically more prepared for transfer to the field.</jats:p>

The CO2 fertilization effect on leaf photosynthesis of maize (Zea mays L.) depends on growth temperatures with changes in leaf anatomy and soluble sugars

“…Response of leaf photosynthesis to elevated CO 2 concentration is also highly dependent on the source-sink balance of carbohydrates, because the excessive carbohydrate accumulation can reduce both the efficiency and content of Rubisco through sucrose cycling and photosynthetic gene repression of plants under higher CO 2 concentrations (Córdoba et al, 2017), and thus the imbalance between sink and source carbohydrates may lower the CO 2 fertilization effect on leaf photosynthesis (Fan et al, 2020). Elevated CO 2 concentration can drastically enhance the growth and crop yield of plants through the "CO 2 fertilization effect, " which is attributed to the increases of starch and soluble sugars in plant leaves (Pérez-Jiménez et al, 2017;Habermann et al, 2019). Interestingly, our results showed that the soluble sugars in maize leaves were substantially increased by elevated CO 2 concentration even at the highest temperature regime of 37/31°C.…”