Possible Activation of С3 Photosynthesis in С4 Halophyte Kochia prostrata Exposed to an Elevated Concentration of СО2

• Published in: Russian journal of plant physiology 2021-11, Vol.68 (6), p.1107-1114
• Main Authors: Rakhmankulova, Z. F., Shuyskaya, E. V., Prokofieva, M. Yu
• Format: Article
• Language: English
• Subjects: Biomedical and Life Sciences; Growth rate; Halophytes; Immunoblotting; Ions; Kochia prostrata; Life Sciences; Oxidation; Oxygenase; Phosphoenolpyruvate carboxylase; Photosynthesis; Photosystem I; Photosystem II; Plant Physiology; Plant Sciences; Potassium; Proline; Research Papers; Ribulose-1,5-bisphosphate; Ribulose-bisphosphate carboxylase; Shoots; Sodium
• ISSN: 1021-4437; 1608-3407
• DOI: 10.1134/S1021443721060169

The effect of an elevated concentration of СО 2 (800 ppm) on the growth rate, efficiency of photosystem I (PS I) and photosystem II (PS II), content of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) and phosphoenolpyruvate carboxylase (PEPc), as well as proline and sodium and potassium ions, was investigated in the shoots of С 4 -halophyte Kochia prostrata (L.) Schrad. An elevated concentration of СО 2 caused a decrease in accumulation of dry biomass (1.2 times), a rise in the content of proline (1.2 times) and potassium ions (1.3 times), and a shortening of time required to reach the maximum P700 oxidation level (PS I) (1.7 times). The content of sodium ions and water in the shoots and efficiency of PS II ( F v / F m ) did not change. Immunoblotting showed that, at the elevated concentration of СО 2 , the ratio between Rubisco and PEPc proteins rose from 1.3 to 3.4. The shortening of time required to reach the maximum oxidation level of PS I indirectly points to a reduction in the activity of cyclic transport of electrons responsible for efficient operation of the С 4 -carbon-concentrating mechanism. The high concentration of СО 2 is suggested to activate the С 3 -pathway of photosynthesis in С 4 -halophyte K. prostrata.