Photosynthesis, photorespiration and productivity of wheat and soybean genotypes^†

Abstract

The results of the numerous measurements obtained during the last 40 years on gas exchange rate, photosynthetic carbon metabolism by exposition in ¹⁴CO₂ and activities of primary carbon fixation enzyme, ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBPC/O), in various wheat and soybean genotypes grown over a wide area in the field and contrasting in photosynthetic traits and productivity are presented in this article. It was established that high productive wheat genotypes (7-9 t ha⁻¹) with the optimal architectonics possess higher rate of CO₂ assimilation during the leaf ontogenesis. Along with the high rate of photosynthesis, high values of photorespiration are characteristic for the high productive genotypes. Genotypes with moderate (4-5 t ha⁻¹) and low (3 t ha⁻¹) grain yield are characterized by relatively low rates of both CO₂ assimilation and photorespiration. A value of photorespiration constitutes 28-35% of photosynthetic rate in contrasting genotypes. The activities of RuBPC and RuBPO were changing in a similar way in the course of the flag leaf and ear elements development. High productive genotypes are also characterized by a higher rate of biosynthesis and total value of glycine-serine and a higher photosynthetic rate. Therefore, contrary to conception arisen during many years on the wastefulness of photorespiration, taking into account the versatile investigations on different aspects of photorespiration, it was proved that photorespiration is one of the evolutionarily developed vital metabolic processes in plants and the attempts to reduce this process with the purpose of increasing the crop productivity are inconsistent.

Mitochondrial Dihydrolipoyl Dehydrogenase Activity Shapes Photosynthesis and Photorespiration of Arabidopsis thaliana

“…This view is changing and the repair function of photorespiration becomes more appreciated, for example, in light of new data on the evolution of photorespiration (Eisenhut et al, 2008;Hagemann et al, 2013) and field studies that demonstrated a positive correlation between photorespiration and yield for a number of highly productive wheat cultivars (Aliyev, 2012). Building upon our initial H-protein study (Timm et al, 2012a) and the data presented in this article, we envisage the following cause/effect relationship.…”

Optimizing photorespiration for improved crop productivity

“…Although this mutational approach efficiently deciphered the photorespiratory pathway, it did not reveal strategies to optimize the pathway for improved growth. Furthermore, a comprehensive study analyzing data from 40 years of field trials, in soybean and wheat, showed that cultivars with increased photosynthetic rates also had higher rates of photorespiration, suggesting that using natural variation in photorespiration to identify plants with lower levels of photorespiration and higher productivity would likely not be successful (Aliyev ). Yet, studies of natural variation in photorespiration, in tobacco, described the selection of plants with low photorespiration, which also exhibited higher rates of photosynthesis and growth.…”

Simultaneous analysis of ten low‐molecular‐mass organic acids in the tricarboxylic acid cycle and photorespiration pathway in Thalassiosira pseudonana at different growth stages

“…In particular, glycolic acid and glyoxylic acid are the primary metabolites in the photorespiration pathway, which consume energy and releases fixed carbon in the plant . Although photorespiration limits plant productivity, it is closely associated with photosynthesis and interacts with redox signaling cascades to control plant growth .…”