PHOTOSYNTHETICA

Photosynthetica 2023, 61(2):190-202 | DOI: 10.32615/ps.2022.047

Changes in the photosynthetic performance, the activity of enzymes of nitrogen metabolism, and proline content in the leaves of wheat plants after exposure to low CO₂ concentration

A. IVANOV¹, A. KOSOBRYUKHOV¹, V. KRESLAVSKI¹, S.I. ALLAKHVERDIEV^{1, 2, 3, 4}

¹ Institute of Basic Biological Problems, Russian Academy of Sciences, Institutskaya Street 2, Pushchino, 142290 Moscow Region, Russia

² K.A. Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya Street 35, 127276 Moscow, Russia

³ Faculty of Science, King Abdulaziz University, 21589 Jeddah, Saudi Arabia

⁴ Faculty of Engineering and Natural Sciences, Bahcesehir University, Istanbul, Turkey

The changes in photosynthetic activity, as well as the activity of nitrogen-metabolism enzymes, the intensity of lipid peroxidation, and proline content were studied in Triticum aestivum L. plants after their incubation at a low CO₂ concentration in a sealed chamber for 10 d. CO₂ deficiency (-CO₂) compared to normal CO₂ concentration (control) led to a decrease in the rate of O₂ gas exchange at the plateau of the light curve and quantum yield of photosynthesis. The maximum and effective quantum photochemical yields also decreased. CO₂ deficiency reduced the activity of nitrate reductase, but increased the activities of nitrite reductase, glutamine synthetase, and glutamate dehydrogenase, and promoted proline accumulation. It is assumed that with a lack of CO₂, an excess of nitrogen-containing compounds occurs, which must be removed from metabolic processes. Also, we suggest the partial storage of nitrogen in the form of nitrogen-containing compounds such as proline.

Additional key words: chlorophyll fluorescence; growth; low CO₂; nitrogen cycle; photosynthetic activity.

Received: October 5, 2022; Revised: October 22, 2022; Accepted: November 11, 2022; Prepublished online: December 1, 2022; Published: June 6, 2023  Show citation